Effects of Fat Sources on Growth Performance, Nutrient Digestibility, Serum-pigs

第33卷第1期赵季飞等:亚磷酸三苯酯)))一种锂离子电池电解液稳定剂化学试剂,2011,33(1),69~71亚磷酸三苯酯)))一种锂离子电池电解液稳定剂赵季飞,李冰川,苏建军,廖红英,王磊,付呈琳,孟蓉*(北京化学试剂研究所,北京 102607)摘要:以标题化合物为锂离子电池电解液添加剂,提高了锂离子电池电解液在贮存和高温条件下的色度稳定性。

通过测定不同亚磷酸三苯酯添加量下电解液的色度及电导率,得出亚磷酸三苯酯的最佳添加量为012%。

电化学测试结果表明,亚磷酸三苯酯的添加不影响锂离子电池的充放电及循环性能。

关键词:锂离子电池电解液;品质控制;稳定剂;亚磷酸三苯酯中图分类号:O 627151 文献标识码:A 文章编号:0258-3283(2011)01-0069-03收稿日期:2010-07-17作者简介:赵季飞(1983-),女,山东莱阳人,硕士,工程师,主要从事锂离子电池电解液的研发与生产工作。

联系作者:孟蓉,E-m ai:l 136********@s ohu.co m 。

电解液作为锂离子电池的重要组成部分,其稳定的性能是锂离子电池工作的重要保证。

锂离子电池电解液在运输和贮存的过程中,尤其在高温贮存过程中,容易变色。

一般情况下,锂离子电池电解液在50e 环境下,存放24h 即会色泽变深,导致电解液品质发生变化,影响锂离子电池各项性能的发挥。

在高温条件下,电解质六氟磷酸锂(L i P F 6)可分解成五氟化磷(PF 5),而PF 5引起碳酸乙烯酯、碳酸二甲酯或电解液中质子溶剂杂质等的聚合,生成可溶性单聚物、二聚物、齐聚物[1-7],随着聚合物中共轭体系的增加,聚合物光谱红移显现成色基团,导致电解液色度增大。

随着聚合度的增加,电解液颜色越来越深。

亚磷酸酯类化合物具有还原性,可作为抗氧剂应用于锂离子电池电解液中,推测亚磷酸三苯酯在锂离子电池电解液中的作用机理如下:亚磷酸三苯酯[TPP(i)]作用于PF 5催化下的溶剂聚合反应,可阻断链式聚合过程,使PF 5对聚合反应的催化作用失效,从而稳定了电解液的色度。

脂肪是个好东西英语作文Fat is a Good ThingFat is often viewed in a negative light, associated with health problems and an unsightly appearance. However, this perception of fat is misguided and oversimplified. In reality, fat is an essential and beneficial component of the human body, serving a variety of crucial functions. While it is true that excessive fat can lead to various health concerns, a balanced and moderate amount of fat is not only necessary but also advantageous for overall well-being.One of the primary roles of fat is to provide energy for the body. Fat is a highly efficient fuel source, containing more than twice the energy content of carbohydrates and proteins. When the body's energy needs are not met through dietary intake, it turns to fat stores for the necessary fuel. This process is particularly important during periods of fasting or prolonged physical activity, when the body requires a reliable and readily available energy source. Without adequate fat reserves, the body would struggle to maintain its basic functions and would be more susceptible to fatigue and weakness.In addition to its energy-providing capabilities, fat also plays a crucialrole in the absorption and transportation of essential vitamins and minerals. Certain vitamins, such as vitamins A, D, E, and K, are fat-soluble, meaning they can only be properly absorbed and utilized by the body when accompanied by fat. By facilitating the absorption of these vital nutrients, fat helps to ensure that the body can effectively utilize the full spectrum of essential vitamins and minerals obtained through diet.Fat also serves as an important insulator for the body, helping to regulate body temperature and protect vital organs from the elements. The layer of fat beneath the skin, known as subcutaneous fat, acts as a natural barrier against the cold, preventing heat loss and maintaining a stable core body temperature. This insulating property is particularly crucial in colder climates, where the body's ability to retain heat is essential for survival and overall health.Furthermore, fat plays a crucial role in the production of hormones, which are essential for a wide range of bodily functions. Hormones such as estrogen, testosterone, and cortisol are synthesized from cholesterol, a type of fat. These hormones regulate various physiological processes, including metabolism, growth, and sexual function. Without an adequate supply of fat, the body would be unable to produce the necessary hormones, leading to hormonal imbalances and a host of related health issues.It is also important to recognize that fat serves as a valuable source of essential fatty acids, which are necessary for the proper functioning of the brain, heart, and other vital organs. Omega-3 and omega-6 fatty acids, for example, are critical for maintaining cognitive function, reducing inflammation, and supporting cardiovascular health. These essential fatty acids can only be obtained through dietary sources, and fat-rich foods are a primary means of acquiring them.While it is true that excessive fat accumulation can lead to health problems such as obesity, type 2 diabetes, and heart disease, the solution is not to completely eliminate fat from the diet. Instead, the focus should be on maintaining a balanced and healthy intake of various types of fat. This includes incorporating a variety of unsaturated fats, such as those found in nuts, avocados, and olive oil, while limiting the consumption of saturated and trans fats, which are more closely linked to negative health outcomes.In conclusion, fat is a vital and multifaceted component of the human body, serving essential functions that are crucial for overall health and well-being. From providing energy and facilitating nutrient absorption to regulating body temperature and producing hormones, fat plays a vital role in the proper functioning of the body. While it is important to be mindful of the potential risks associated with excessive fat accumulation, a balanced and moderate intake ofhealthy fats is not only beneficial but necessary for maintaining optimal physical and mental health.。

辛建增，唐婷，刘盛．ＰＧＣ－ｌα调控畜禽肌肉脂肪生长代谢及其与肉品质研究进展［Ｊ］．畜牧与兽医，２０２４，５６（５）：１３８－１４５．ＸＩＮＪＺ，ＴＡＮＧＴ，ＬＩＵＳ．Ｐｒｏｇｒｅｓｓｉｎｒｅｓｅａｒｃｈｏｎｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｒｅｇｕｌａｔｉｏｎｏｆｐｅｒｏｘｉｓｏｍｅｐｒｏｌｉｆｅｒａｔｏｒ－ａｃｔｉｖａｔｅｄｒｅｃｅｐｔｏｒγ－ｃｏａｃｔｉｖａｔｏｒ－１αｏｎｇｒｏｗｔｈａｎｄｍｅｔａｂｏｌｉｓｍｏｆｍｕｓｃｌｅａｎｄｆａｔａｎｄｍｅａｔｑｕａｌｉｔｙｉｎｌｉｖｅｓｔｏｃｋａｎｄｐｏｕｌｔｒｙ［Ｊ］．ＡｎｉｍａｌＨｕｓｂａｎｄｒｙ＆ＶｅｔｅｒｉｎａｒｙＭｅｄｉｃｉｎｅ，２０２４，５６（５）：１３８－１４５．ＰＧＣ－ｌα调控畜禽肌肉脂肪生长代谢及其与肉品质研究进展辛建增１，唐婷１，刘盛２∗（１．烟台大学生命科学学院，山东烟台㊀２６４０００；２．烟台大学药学院，山东烟台㊀２６４０００）摘要：过氧化物酶体增殖物激活受体γ辅激活因子１α（ＰＧＣ－ｌα）是一种具有广泛功能的转录调节因子，其在动物体内参与线粒体生物合成㊁肌纤维类型转化㊁脂肪分化㊁肌内脂肪沉积㊁糖脂代谢㊁能量代谢等多项生理过程，其中，肌纤维类型和肌内脂肪含量与肉品质密切相关㊂因此，在分子水平深入探究ＰＧＣ－１α调控肌肉和脂肪的生长代谢过程将为改善肉品质提供新的研究思路㊂本文系统概述了ＰＧＣ－ｌα的结构特点及ＰＧＣ－１α调控肌肉线粒体增生㊁脂肪分化㊁能量代谢等过程的机制，重点介绍了ＰＧＣ－ｌα调控肌纤维类型转化㊁肌内脂肪沉积㊁糖类代谢及其与肉品质形成之间的可能关系，以期为今后通过ＰＧＣ－１α调控畜禽肌肉脂肪生长代谢，进而改善肉品质提供参考㊂关键词：过氧化物酶体增殖物激活受体γ辅激活因子１α；肌纤维类型；肌内脂肪沉积；能量代谢；肉品质中图分类号：Ｓ８２６㊀㊀㊀文献标志码：Ａ㊀㊀㊀文章编号：０５２９－５１３０（２０２４）０５－０１３８－０８Ｐｒｏｇｒｅｓｓｉｎｒｅｓｅａｒｃｈｏｎｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｒｅｇｕｌａｔｉｏｎｏｆｐｅｒｏｘｉｓｏｍｅｐｒｏｌｉｆｅｒａｔｏｒ－ａｃｔｉｖａｔｅｄｒｅｃｅｐｔｏｒγ－ｃｏａｃｔｉｖａｔｏｒ－１αｏｎｇｒｏｗｔｈａｎｄｍｅｔａｂｏｌｉｓｍｏｆｍｕｓｃｌｅａｎｄｆａｔａｎｄｍｅａｔｑｕａｌｉｔｙｉｎｌｉｖｅｓｔｏｃｋａｎｄｐｏｕｌｔｒｙＸＩＮＪｉａｎｚｅｎｇ１，ＴＡＮＧＴｉｎｇ１，ＬＩＵＳｈｅｎｇ２∗（１．ＣｏｌｌｅｇｅｏｆＬｉｆｅＳｃｉｅｎｃｅｓ，ＹａｎｔａｉＵｎｉｖｅｒｓｉｔｙ，Ｙａｎｔａｉ２６４０００，Ｃｈｉｎａ；２．ＣｏｌｌｅｇｅｏｆＰｈａｒｍａｃｙ，ＹａｎｔａｉＵｎｉｖｅｒｓｉｔｙ，Ｙａｎｔａｉ２６４０００，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：Ｐｅｒｏｘｉｓｏｍｅｐｒｏｌｉｆｅｒａｔｏｒ－ａｃｔｉｖａｔｅｄｒｅｃｅｐｔｏｒγ（ＰＰＡＲ－γ）ｃｏａｃｔｉｖａｔｏｒ１α（ＰＧＣ－ｌα）ｉｓａｖｅｒｓａｔｉｌｅｔｒａｎｓｃｒｉｐｔｉｏｎａｌｒｅｇｕｌａｔｏｒ．Ｔｈｉｓｒｅｇｕｌａｔｏｒｉｓｉｎｖｏｌｖｅｄｉｎｍａｎｙｐｈｙｓｉｏｌｏｇｉｃａｌｐｒｏｃｅｓｓｅｓｓｕｃｈａｓｍｉｔｏｃｈｏｎｄｒｉａｌｂｉｏｓｙｎｔｈｅｓｉｓ，ｍｕｓｃｌｅｆｉｂｅｒｔｙｐｅｔｒａｎｓｆｏｒｍａｔｉｏｎ，ａｄｉｐｏｓｅｄｉｆｆｅｒｅｎｔｉ⁃ａｔｉｏｎ，ｉｎｔｒａｍｕｓｃｕｌａｒａｄｉｐｏｓｅｄｅｐｏｓｉｔｉｏｎ，ｇｌｙｃｏｌｉｐｉｄｍｅｔａｂｏｌｉｓｍ，ａｎｄｅｎｅｒｇｙｍｅｔａｂｏｌｉｓｍｉｎａｎｉｍａｌｓ．Ｍｕｓｃｌｅｆｉｂｅｒｔｙｐｅａｎｄｉｎｔｒａｍｕｓｃｕｌａｒｆａｔｃｏｎｔｅｎｔａｒｅｃｌｏｓｅｌｙｒｅｌａｔｅｄｔｏｍｅａｔｑｕａｌｉｔｙ．Ｔｈｅｒｅｆｏｒｅ，ｅｘｐｌｏｒｉｎｇｔｈｅｒｅｇｕｌａｔｉｏｎｏｆＰＧＣ－１αｏｎｔｈｅｇｒｏｗｔｈａｎｄｍｅｔａｂｏｌｉｓｍｏｆｍｕｓｃｌｅａｎｄｆａｔａｔｔｈｅｍｏｌｅｃｕｌａｒｌｅｖｅｌｗｉｌｌｐｒｏｖｉｄｅｎｅｗｒｅｓｅａｒｃｈｉｄｅａｓｆｏｒｉｍｐｒｏｖｉｎｇｍｅａｔｑｕａｌｉｔｙ．Ｉｎｔｈｉｓｐａｐｅｒ，ｔｈｅｓｔｒｕｃｔｕｒａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＰＧＣ－ｌαａｎｄｔｈｅｍｅｃｈａｎｉｓｍｏｆＰＧＣ－１αｒｅｇｕｌａｔｉｎｇｍｕｓｃｌｅｍｉｔｏｃｈｏｎｄｒｉａ，ａｄｉｐｏｓｅｄｉｆｆｅｒｅｎｔｉａｔｉｏｎａｎｄｅｎｅｒｇｙｍｅｔａｂｏｌｉｓｍａｒｅｓｙｓｔｅｍａｔｉｃａｌｌｙｒｅｖｉｅｗｅｄ．Ｔｈｅｒｅｇｕ⁃ｌａｔｉｏｎｏｆＰＧＣ－ｌαｏｎｍｕｓｃｌｅｆｉｂｅｒｔｙｐｅｔｒａｎｓｆｏｒｍａｔｉｏｎ，ｉｎｔｒａｍｕｓｃｕｌａｒｆａｔｄｅｐｏｓｉｔｉｏｎ，ｃａｒｂｏｈｙｄｒａｔｅｍｅｔａｂｏｌｉｓｍａｎｄｉｔｓｐｏｓｓｉｂｌｅｒｅｌａｔｉｏｎｓｈｉｐｗｉｔｈｔｈｅｆｏｒｍａｔｉｏｎｏｆｍｅａｔｑｕａｌｉｔｙａｒｅｅｍｐｈａｓｉｚｅｄ；ｗｈｉｃｈｐｒｏｖｉｄｅｓｒｅｆｅｒｅｎｃｅｆｏｒｉｍｐｒｏｖｉｎｇｍｅａｔｑｕａｌｉｔｙｂｙｒｅｇｕｌａｔｉｎｇｔｈｅｇｒｏｗｔｈａｎｄｍｅｔａｂｏ⁃ｌｉｓｍｏｆｍｕｓｃｌｅａｎｄｆａｔｂｙＰＧＣ－１αｉｎｌｉｖｅｓｔｏｃｋａｎｄｐｏｕｌｔｒｙ．Ｋｅｙｗｏｒｄｓ：ＰＧＣ－１α；ｍｕｓｃｌｅｆｉｂｅｒｔｙｐｅ；ｉｎｔｒａｍｕｓｃｕｌａｒｆａｔｄｅｐｏｓｉｔｉｏｎ；ｅｎｅｒｇｙｍｅｔａｂｏｌｉｓｍ；ｍｅａｔｑｕａｌｉｔｙ㊀㊀畜禽肉品质包括肉色㊁嫩度㊁系水力㊁风味㊁多汁性等多个方面㊂因此，肉品质性状是一个复杂的综合性状㊂肉品质受宰前和宰后多种因素的影响，例如遗传（品种㊁性别㊁年龄㊁基因）㊁营养水平㊁饲养管理㊁宰前运输㊁屠宰方式㊁宰后成熟方式等，其中㊀收稿日期：２０２３－０５－２５；修回日期：２０２４－０３－２０基金项目：烟台大学博士启动基金项目（ＳＭ２０Ｂ１１３）第一作者：辛建增，男，博士，讲师∗通信作者：刘盛，讲师，研究方向为食品化学，Ｅ－ｍａｉｌ：ｌｉｕｓｈ⁃ｅｎｇ８７＠１２６ ｃｏｍ㊂遗传因素起决定性作用㊂然而，在饲养过程中，畜禽肌肉和脂肪的生长发育及代谢对肉品质的形成也起着至关重要作用㊂畜禽肌肉的生长发育及代谢是一个及其复杂的过程，由多种基因和信号通路在不同水平上参与调控，各调控因子与信号通路分工协作组成精细复杂的调控网络，有序调控肌肉的生长发育㊁肌纤维类型的转化㊁肌纤维的能量代谢等生物学过程㊂而脂肪组织是畜禽维持生命活动必不可少的组织，通常储存在皮下㊁内脏㊁肌肉等部位㊂与肉品质最相关的脂肪为肌内脂肪和肌间脂肪㊂其中肌内脂肪的含量与肉品质最为密切，是肉品领域的研究热点，肌内脂肪的含量会影响肉的系水力㊁风味㊁多汁性等品质㊂过氧化物酶体增殖物激活受体γ辅激活因子１α（ＰＧＣ－１α）是肌肉和脂肪生长代谢过程中必需的转录共调节因子，它参与调控肌细胞线粒体生物合成㊁肌纤维类型的转化㊁肌细胞能量代谢等生物学过程㊂ＰＧＣ－１α在脂肪的分化㊁沉积㊁合成㊁代谢等方面也发挥重要的调节作用㊂此外，ＰＧＣ－１α还参与机体的适应性产热㊁肝脏的糖异生㊁血管生成㊁调控细胞中活性氧簇水平㊁调控机体的生物钟基因等生理过程㊂ＰＧＣ－１α功能广泛，参与众多生理调节过程㊂本文将对ＰＧＣ－１α分子结构特征，ＰＧＣ－１α调控肌纤维能量代谢㊁肌纤维糖代谢㊁肌纤维类型转化㊁脂肪分化㊁肌内脂肪沉积㊁脂肪代谢及其与宰后肉品质的可能关系进行了系统阐述，并对相关可能的研究热点进行了展望㊂以期为更深入地探究ＰＧＣ－１α信号通路及其靶基因调控畜禽肌肉脂肪生长代谢和提高肉品质提供参考㊂１㊀ＰＧＣ－１α概述ＰＧＣ－１α是由Ｓｐｉｅｇｅｌｍａｎ团队１９９８年最先在小鼠棕色脂肪组织中发现的一种转录共调节因子［１］㊂ＰＧＣ－１α属于ＰＧＣ－１家族，该家族共有３个成员，另外两个分别为过氧化物酶体增殖物激活受体γ（ＰＰＡＲ－γ）辅激活因子－１β（ＰＧＣ－１β）和ＰＧＣ－１相关辅活化因子（ＰＲＣ），其家族成员蛋白长度存在着一定的差异，但存在着相应的保守序列㊂ＰＧＣ－１家族的Ｎ端结构域均含有转录激活域，Ｃ端结构域均包含富含丝氨酸／精氨酸的ＲＳ域和ＲＮＡ结合区域（ＲＭＭ）［２］㊂ＰＧＣ－１α与ＰＧＣ－ｌβ同源性较高，而与ＰＲＣ的同源性则相对较低㊂人的ＰＧＣ－１α基因位于染色体４ｐ１５ １区域，全长为６８１ｋｂ，由１３个外显子和１２个内含子组成，其ｍＲＮＡ含有６９０８ｂｐ，编码一个包含７９８个氨基酸，分子量９１ｋＤａ的蛋白质［３］，其他常见畜禽的ＰＧＣ－１α基因与蛋白质基本信息见表１（引自ＮＣＢＩ）㊂ＰＧＣ－１α的蛋白结构域，其Ｎ端有一个富含酸性氨基酸的转录激活区（ａｃｔｉｖａｔｉｏｎｄｏｍａｉｎ，ＡＤ），该区内有一个ＬＸＸＬＬ结构域（Ｘ：任意氨基酸；Ｌ：亮氨酸），此结构域是ＰＧＣ－１α与配体依赖型核受体结合的基础㊂负调控元件和转录因子结合位点位于ＰＧＣ－１α的中间区域，当转录因子与ＰＧＣ－１α结合时，负调控元件就会暴露出来［４］㊂Ｃ末端是一个ＲＮＡ结合基本序列ＲＲＭ和富含丝氨酸／精氨酸的ＲＳ区域，这个区域可以与ＲＮＡ聚合酶Ⅱ的Ｃ末端相互作用，处理新转录的ＲＮＡ㊂ＰＧＣ－１α上还有与细胞呼吸因子（ＮＲＦ）㊁肌细胞特异性增强子２Ｃ（ｍｙｏｃｙｔｅｅｎｈａｎｃｅｒｆａｃｔｏｒ２Ｃ，ＭＥＦ２Ｃ）及ＰＰＡＲγ结合的位点［３］㊂因此，ＰＧＣ－１α是作为转录因子的激活因子来调控其他基因的表达㊂表１㊀人与常见畜禽ＰＧＣ－１α基因和蛋白质基本信息物种所处染色体基因长度／ｋｂｍＲＮＡ长度／ｂｐ内含子数外显子数蛋白肽链长度（氨基酸残基数量）蛋白质分子量／ｋＤａ人４６８１６９０８１２１３８０３９２猪８６９６６７３８１２１３７９６９０狗３６４１５８４１１３１４８０３９１牛６７１５６３２４１２１３７９６９０羊６７１８６６８０１２１３７８７８９鸡４３４８６６１５１２１３８０８９２鸭４３６１９７１６１２１３８０８９２鸽子４３６４４９１３１２１３６７０７７㊀㊀ＰＧＣ－１α分子本身的促转录激活活性较低，只有被相应的受体募集后，其活性才显著增强㊂ＰＧＣ－１α与核受体结合后，会导致ＰＧＣ－１α构象发生改变，并与下游因子作用，发挥转录激活作用㊂ＰＧＣ－１α不仅对ＰＰＡＲγ具有组织特异性的辅激活作用，而且也是类维生素ＡＸ受体（ＲＸＲ）㊁肌细胞增强因子２ｃ（ｍｙｏｃｙｔｅｅｎｈａｎｃｅｒｆａｃｔｏｒ２Ｃ，ＭＥＦ２Ｃ）㊁甲状腺激素受体（ｔｈｙｒｏｉｄｈｏｒｍｏｎｅｒｅｃｅｐｔｏｒ，ＴＲ）㊁糖皮质激素受体（ｇｌｕｃｏｃｏｒｔｉｃｏｉｄｒｅｃｅｐｔｏｒ，ＧＲ）㊁雌醇受体α（ｅｓ⁃ｔｒｏｇｅｎｒｅｃｅｐｔｏｒ，ＥＲα）和ＰＰＡＲｓ等核受体（ｎｕｃｌｅａｒｒｅｃｅｐｔｏｒ，ＮＲ）的辅激活因子［２，５－７］㊂ＰＧＣ－１α的表达具有组织特异性，通常在线粒体含量丰富和氧化代谢活跃的器官或组织中高表达，如骨骼肌㊁心脏㊁棕色脂肪组织㊁肝脏㊁肾脏和大脑组织等，而在肺㊁小肠㊁结肠和胸腺中只有很少量的表达，在胎盘㊁脾和外周白细胞中未见表达［８］㊂前已述及，ＰＧＣ－１α在肌肉脂肪的生长发育及代谢中发挥着重要调控作用，下面将针对其活性调控㊁肌肉脂肪生长代谢及其与肉品质和一些生理功能的相关作用进行论述㊂２㊀ＰＧＣ－１α活性调控相关信号因子ＰＧＣ－１α含有磷酸化㊁乙酰化㊁糖基化㊁甲基化㊁泛素化等翻译后修饰的位点，这些翻译后修饰对于其发挥作用时的精细化调控具有重要意义［９］㊂其中当前研究较多的为乙酰化和磷酸化修饰㊂沉默信息调节因２相关酶１（ｓｉｒｔｕｉｎ１，ＳＩＲＴ１）和ＡＭＰ依赖的蛋白激酶（ａｄｅｎｏｓｉｎｅ５－ｍｏｎｏｐｈｏｓｐｈａｔｅ－ａｃｔｉｖａｔｅｄｐｒｏｔｅｉｎｋｉｎａｓｅ，ＡＭＰＫ）是调控ＰＧＣ－１α去乙酰化和磷酸化的关键酶，此两种酶对于机体肌肉脂肪生长发育和能量代谢的精准调控和稳态维持具有重要的意义㊂ＳＩＲＴ１可以将乙酰化后的ＰＧＣ－１α去乙酰化，从而提高ＰＧＣ－１α的活性［１０－１１］㊂此外ＳＩＲＴ１是体内代谢的感受器，当机体处于能禁食或者饥饿等状态下，ＳＩＲＴ１会加速ＰＧＣ－１α的去乙酰化，导致其活性上升，可增加线粒体的合成㊂而一些乙酰转移酶例如组蛋白乙酰化酶氨合成通用控制蛋白５（ｈｉｓｔｏｎｅａｃｅｔｙｌ⁃ｔｒａｎｓｆｅｒａｓｅＧＣＮ５，ＧＣＮ５）和核受体共激活因子－３（ｓｔｅｒｏｉｄｒｅｃｅｐｔｏｒｃｏａｃｔｉｖａｔｏｒ３，ＳＲＣ－３）可以使ＰＧＣ－１α发生乙酰化，从而抑制其活性［１２－１５］㊂此外，ＳＩＲＴ１的去乙酰化作用还是ＰＧＣ－１α调控生物钟基因表达的重要事件㊂ＳＩＲＴ１与乙酰化酶协调作用，精细化调节ＰＧＣ－１α发挥作用㊂ＡＭＰＫ是体内能量感受器，当机体能量处于缺乏状态时，ＡＭＰＫ可使ＰＧＣ－１α磷酸化位点磷酸化，从而提高ＰＧＣ－１α活性，激活与能量代谢相的通路，引起线粒体增生㊁脂肪酸氧化等生物学过程增加［１４］㊂３㊀ＰＧＣ－１α与肌肉生长代谢及肉品质３ １㊀ＰＧＣ－１α与肌肉线粒体合成及肉品质线粒体是为骨骼肌生长发育提供能量的细胞器，它对骨骼肌发挥正常生理功能具有重要的意义，ＰＧＣ－１α是调控线粒体生物合成和氧化磷酸化过程中的关键调节因子［１５－１６］㊂研究发现，ＰＧＣ－１α可参与调控肌纤维中线粒体的生成，并且还能够调节线粒体的融合及分裂，在某些组织，如白色脂肪㊁肌肉㊁神经㊁心脏中超表达ＰＧＣ－１α，都会促进线粒体的生成［１５－１７］㊂ＰＧＣ－１α促进线粒体生成主要通过与转录因子结合发挥作用，常见的为核呼吸因子－１（ｎｕｃｌｅａｒｒｅｓｐｉｒａｔｏｒｙｆａｃｔｏｒ－１，ＮＲＦ－１）和核呼吸因－２（ｎｕｃｌｅａｒｒｅｓｐｉｒａｔｏｒｙｆａｃｔｏｒ－２，ＮＲＦ－２）㊂研究发现，ＰＧＣ－１α与核呼吸因子结合后会刺激线粒体转录因子Ａ（ｍｉｔｏｃｈｏｎｄｒｉａｌｔｒａｎｓｃｒｉｐｔｉｏｎｆａｃｔｏｒＡ，ｍｔＴＦＡ）的合成㊂这些因子直接影响线粒体生成，在线粒体内引起线粒体ＤＮＡ的双向转录，实现了线粒体的增殖［１８－１９］㊂畜禽宰杀放血后，肌肉中的线粒体发生肿胀，最终结构破坏而破裂，但肉品质形成过程中，线粒体的生理代谢状态与肉嫩度㊁肉色㊁持水力等品质有着密切关系㊂研究表明，宰后初期肌肉线粒体耗氧率与肉品嫩度密切相关，高嫩度牛肉拥有更高的线粒体耗氧率［２０］㊂宰后肌肉中线粒体影响肉色稳定性主要通过两种途径，一是线粒体与氧合肌红蛋白竞争氧气，使其转变为脱氧肌红蛋白状态，此情况过度发生可导致肉色变暗；另一方面，线粒体具有高铁肌红蛋白还原酶活性，可以将氧化的高铁肌红蛋白转化为还原态脱氧肌红蛋白，为鲜红色氧合肌红蛋白的生成提供还原态肌红蛋白［２１－２２］㊂肌肉持水力是肉品一个重要的品质，最近研究表明，牛肉宰后成熟过程中，线粒体脂肪成分的变化与肌肉持水力的变化密切相关［２３］㊂ＰＧＣ－１α已被证明其与畜禽生长和肉品质密切相关，且已被列为能够候选基因［２４］，然而未见ＰＧＣ－１α调控肌肉中线粒体与宰后肉品质的相关研究，ＰＧＣ－１α对肌肉中线粒体的调控及宰后肉品质的变化形成需要开展深入研究㊂３ ２㊀ＰＧＣ－１α与肌肉糖类代谢葡萄糖是肌肉组织主要的能源物质，糖类氧化供能为肌肉的各类生理活动提供能量㊂ＰＧＣ－１α在体内糖代谢的过程中发挥重要调节作用，主要表现在以下几个方面：首先ＰＧＣ－１α是糖异生过程的关键调节因子㊂在禁食情况下，ＰＧＣ－１α会在肝细胞中大量表达，与其他相关调节因子配合在转录水平上激活糖异生关键酶组，如葡萄糖－６－磷酸酶㊁磷酸烯醇式丙酮酸羧激酶等，最终导致肝糖输出增加［２５－２６］㊂其次，葡萄糖进入肌肉细胞需要葡萄糖转运载体４（ｇｌｕｃｏｓｅｔｒａｎｓｐｏｒｔｅｒｓ４，ＧｌｕＴ４）的转运，ＰＧＣ－１α可与肌细胞增强子因子２（ｍｙｏｃｙｔｅｅｎｈａｎｃｅｒｆａｃｔｏｒ２，ＭＥＦ２）共同作用，刺激ＧｌｕＴ４的表达，从而增加肌细胞内葡萄糖的水平㊂此外，ＰＧＣ－１α在某些情况还可抑制肌细胞葡萄糖的氧化，其与雌激素相关受体（ｅｓｔｒｏｇｅｎ－ｒｅｌａｔｅｄｒｅｃｅｐｔｏｒα，ＥＲＲα）结合后，刺激丙酮酸脱氢酶４表达，从而抑制葡萄糖氧化和增加葡萄糖吸收来补充肌糖原贮备，为下一次的肌肉运动做准备㊂肌肉中的糖原是宰后生成乳酸的原料，动物胴体在宰后冷藏排酸过程中，糖原转化为乳酸导致肌肉ｐＨ值下降，这是宰后肌肉排酸的原理㊂而宰后ｐＨ的下降幅度和速度影响肉品质形成，宰后肌肉ｐＨ值过高或过低都会形成异质肉㊂而ＰＧＣ－１α对于肌肉糖代谢具有调控作用，宰前肌肉中ＰＧＣ－１α的表达水平和活性对于宰后肌肉糖原水平㊁ｐＨ值变化及肉品质形成是否具有影响，未见相关报道，需要开展相应研究㊂３ ３㊀ＰＧＣ－１α与骨骼肌肌纤维类型转换及肉品质不同肌纤维类型对于肌肉发挥生理功能具有重要的作用，比较常见的例子是，动物不同部位的肌肉的肌纤维组成存在着明显差异，且肉品质也存着差别㊂肌肉纤维类型受遗传㊁运动㊁营养㊁和环境等多种因素的影响㊂ＰＧＣ－１α是调控肌纤维类型转变的主要因子，ＰＧＣ－１α基因高表达，可以提高与氧化型肌纤维有关的基因表达，提高细胞色素Ｃ和肌红蛋白的含量提高有氧呼吸能力与线粒体的数量，增强抗疲劳的能力等，主要为使酵解型肌纤维向氧化型肌纤维转化［２７－２８］㊂超表达ＰＧＣ－１α的转基因小鼠，其骨骼肌中Ⅱ型肌纤维表现出Ⅰ型肌纤维的蛋白特性，其中ＴＮＮ１蛋白㊁肌红蛋白和肌钙蛋白Ⅰ明显增加，Ⅱ型肌纤维逐步转化为Ⅰ型肌纤维［２９］㊂人和动物的骨骼肌类型变化研究表明，ＰＧＣ－１α的表达量与快肌纤维的含量成负相关，与慢肌纤维的含量成正相关［３０－３１］㊂相关研究已证实，寒冷可以刺激诱使鸡的胸肌部分从ⅡＢ型转化为ⅡＡ型，而ＰＧＣ－１α的上调表达在其中发挥了关键的作用［３２］㊂ＰＧＣ－１α通过调节肌纤维类型影响畜禽肉品质已经被证实，但是其发挥作用的详细分子机制还不清晰，需要开展相应的深入研究㊂３ ４㊀ＰＧＣ－１α与肌肉中活性氧含量及肉品质ＰＧＣ－１α可促进肌肉等组织中线粒体的合成，还能刺激线粒体呼吸链电子转运活性，从理论上讲，ＰＧＣ－１α将导致细胞内活性氧（ｒｅａｃｔｉｖｅｏｘｙｇｅｎｓｐｅｃｉｅｓ，ＲＯＳ）水平提高，但是实际上并非如此，在肌肉和棕色脂肪中，运动与寒冷环境的暴露均和ＲＯＳ负面影响没有关联，这主要是ＰＧＣ－１α可以增强很多抗氧化酶的表达［３３－３４］㊂即ＰＧＣ－１α有两种能力，刺激线粒体电子转运的同时抑制ＲＯＳ水平㊂这样，肌肉组织，棕色脂肪通过提升线粒体代谢应对外部环境变化的过程中，不会对自身造成氧化损伤㊂而ＲＯＳ与宰后肉品的形成密切相关，动物在宰杀后，ＲＯＳ主要来源于线粒体和脂肪的氧化，产生的ＲＯＳ往往会对某些肉品质，肉色㊁嫩度㊁系水力等产生负面影响［２３，３５］㊂ＲＯＳ与宰后肉品质形成一直是肉品科学领域研究的热点，ＰＧＣ－１α已被证实是影响肉品质的候选基因之一，但是其调控宰后肌肉中ＲＯＳ的作用机制及如何影响肉品质未见相关报道㊂４㊀ＰＧＣ－１α与脂肪生长代谢及肉品质４ １㊀ＰＧＣ－１α与脂肪细胞分化动物脂肪组织中大约１／３是脂肪细胞，其余的２／３是成纤维细胞㊁微血管㊁神经组织和处于不同分化阶段的前脂肪细胞㊂由前脂肪细胞分化为脂肪细胞的过程是一个涉及多个信号通路的复杂调控过程，该过程大致可为４个阶段，分别为生长抑制阶段㊁克隆扩增㊁早期分化和终末分化［３６］㊂ＰＰＡＲｓ在动物脂肪发育分化的早期分化阶段开始发挥调控作用，它们与相应的因子协调作用，共同调节脂肪的增殖分化㊂ＰＰＡＲγ是ＰＰＡＲｓ家族成员，它是脂肪细胞分化的及其的重要因子，其通常可作为前体脂肪分化处于早期分化的标志基因，是脂肪细胞增殖分化过程中起决定性作用的基因㊂研究证实，ＰＰＡＲγ缺失的胚胎干细胞能够分化为多种细胞，但唯独不能分化为脂肪细胞㊂此外，ＰＰＡＲγ基因敲除的小鼠，在胚胎期１０ｄ左右就会死亡，且未在胚胎内检测到脂肪细胞，而正常小鼠在胚胎期１０ｄ即可检测到脂肪细胞的存在［３６］㊂这说明ＰＰＡＲγ在脂肪分化形成过程中起关键作用，ＰＰＡＲγ发挥脂肪分化调控作用时，需要先与ＲＸＲα形成异源二聚体，然后与所调节基因启动子上游的过氧化物酶体增殖物反应元件（ＰＰＲＥ）结合才发挥转录调控作用，而ＰＧＣ－１α作为ＰＰＡＲγ配体，能促进ＰＰＡＲγ与相应调控因子的结合［３７］㊂很多哺乳动物体内存在着白色脂肪组织㊁米色脂肪组织和棕色脂肪组织三种，白色脂肪主要作用为贮存能量，米色脂肪具有贮存能量和非战栗产热的功能，棕色脂肪主要进行非战栗产热㊂在细胞结构和功能上，白色脂肪细胞拥有一个大脂滴用于存贮能量，而棕色脂肪细胞拥有多脂滴㊁多线粒体的结构㊂ＰＧＣ－１α能够促进白色脂肪向棕色脂肪转化，它能够刺激白色脂肪中线粒体的大量生成，还能增加解偶联蛋白１（ＵＣＰ１）等分子的生成，这些改变可使白色脂肪逐渐转化为棕色脂肪组织［３８］㊂４ ２㊀ＰＧＣ－１α与脂肪氧化供能脂肪是畜禽体内重要的储能物质，在冷暴露㊁禁食㊁运动等情况下，可为机体提供能量，其中脂肪酸β氧化产能是其最为主要的供能方式㊂脂肪是也骨骼肌获取能量的重要物质㊂研究表明，过表达ＰＧＣ－１α可增加骨骼肌线粒体的生物合成，也可使脂肪酸氧化相关酶含量上升或者活性增强，从而增加脂肪酸氧化供能［３９－４０］㊂在小鼠骨骼肌和猪前脂肪细胞过表达ＰＧＣ－１α，可促进脂肪酸氧化过程中相关基因肉碱棕榈酰转移酶１β（ＣＰＴ１β）㊁肝型脂肪酸结合蛋白（ＦＡＢＰ１）㊁过氧化物酶酰基辅酶Ａ氧化酶１（ＡＣＯＸ１）㊁中链酰基辅酶Ａ脱氢酶（ＭＣＡＤ）㊁脂肪酸转位酶（ＣＤ３６）等的表达，其中ＣＰＴ１β是脂肪酸氧化过程中的限速酶［３８－４１］㊂ＣＤ３６㊁ＦＡＢＰ１是脂肪酸转运的重要蛋白，可将脂肪酸逐步转运至肌肉等组织，便于氧化供能㊂而ＡＣＯＸ１㊁ＭＣＡＤ是参与脂肪酸氧化过程中的关键酶㊂过表达ＰＧＣ－１α还可促进氧化磷酸化相关基因ＡＴＰＳｙｎｔｈａｓｅ㊁ＣｙｔＣ㊁ＣＯＸⅢ等的表达［２７］㊂而在ＰＧＣ－１ａ敲除后的小鼠表现为心脏功能不全，肌肉耐力下降，轻度心动过缓，心肌脂肪酸氧化能力下降，能量产生减少［４２－４４］㊂以上研究说明ＰＧＣ－１α在肌肉的脂肪酸氧化供能方面起重要的调节作用㊂４ ３㊀ＰＧＣ－１α与肌内脂肪沉积及肉品质肌内脂肪的沉积是一个涉及多种信号通路和代谢因子的复杂过程，ＰＰＡＲｓ家族成员㊁肌内脂肪转运相关因子等发挥了重要的作用㊂ＰＧＣ－１α是ＰＰＡＲｓ家族某些因子的配体，其在肌肉脂肪代谢过程中发挥了重要作用㊂ＰＧＣ－１α不仅能够增加肌肉脂肪的分解代谢（前已述及），而且还可增加肌细胞中脂肪的合成代谢㊂通过肌细胞培养实验和转基因小鼠试验证实，ＰＧＣ－１α不仅能增加脂肪的分解代谢，还可以增加肌细胞内脂肪酸和磷脂等脂肪的合成代谢［４５－４６］，且ＰＧＣ－１α转基因小鼠的脂肪酸转运蛋白等脂质代谢相关蛋白也增加了［４６］㊂ＰＧＣ－１α对于肌内脂肪的双向调控作用，对于动物维持生命活动具有重要的意义，不仅能够保障机体对于能量的需求，还对机体后续的生命活动具有重要的意义㊂其发挥脂肪调控作用，还要取决于动物机体所处的状态㊂畜禽上的相关研究已经证实，ＰＧＣ－１α与脂肪沉积及肉品质存在一定关联㊂在猪上的研究表明，ＰＧＣ－１α参与猪脂肪沉积的基因，ＰＧＣ－１α基因多态性与失水率㊁剪切力等肉品指标显著相关［４７－４９］㊂因此，ＰＧＣ－１α已被列为猪脂肪沉积及肉品质的候选基因，且在藏猪上的研究表明ＰＧＣ－１α与肌内脂肪沉积密切相关［３６］㊂在鸡上的研究也证实，ＰＧＣ－１α多态性与鸡腹部脂肪的沉积显著相关［５０－５１］㊂然而，在牛上的研究表明，肌内脂肪含量及嫩度等品质与ＰＧＣ－１α存在一定的相关性，但是未达到显著水平［５２］㊂以上研究表明由于遗传背景的差异，不同畜禽ＰＧＣ－１α在调控肌肉脂质代谢方面可能存在着差异㊂但是当前研究大多停留在分析推测层面，并未对其作用的机理及信号通路作用方式进行深入研究，因此需要对ＰＧＣ－１α调控肌肉代谢，尤其是调控脂肪代谢开展深入的研究，为优质肉品的生产提供研究基础㊂４ ４㊀ＰＧＣ－１α与机体的适应性产热适应性产热是机体应对外界刺激以产热的形式消耗能量的生理过程，对于动物在特定环境下，维持正常体温和生命活动是必须的，主要发生在骨骼肌和棕色脂肪组织㊂其中小型动物，如小鼠，大鼠等主要依靠棕色脂肪组织进行适应性产热，而畜禽则以肌肉适应性产热为主㊂棕色脂肪的分化形成需要ＰＰＡＲγ发挥作用，但其发挥作用需要ＰＧＣ－１α的辅助，ＰＧＣ－１α结合并激活ＰＰＡＲγ后才能刺激棕色脂肪细胞分化过程中基因的转录［１５，５３－５４］㊂ＰＧＣ－１α还可通过另外两个方面来加快适应性产热，首先是促进适应性产热原料的摄取，促进棕色脂肪和肌肉对产热原料，如葡萄糖和脂肪的摄取；促进适应性产热过程中关键因子的合成及表达，主要是为了适应性产热过程的顺利进行，如促进线粒体的生物合成，促进呼吸链相关基因的表达，促进氧化磷酸化相关基因的表达等［５５－５６］㊂当前未见ＰＧＣ－１α调控畜禽适应性产热与肉品质的相关研究，但宰后迅速科学降低屠体的温度，防止肉品质因为过热而出现变质是当前肉品科学领域的一个重要的研究方向㊂５㊀ＰＧＣ－１α与生物钟相互反馈调控畜禽骨骼肌代谢㊀㊀生物钟是生物机体生命活动的内在节律性㊂体温㊁血压㊁睡眠㊁内分泌㊁肝脏代谢㊁行为等重要生命活动均受到生物钟相关基因的调控［５７－５９］，研究表明生物钟还可参与调控细胞周期［６０］㊂其中昼夜节律及光照是调节生物钟基因表达的最常见的外部环境因素，这些因素的变化会影响畜禽的生长发育和动物性产品的质量㊂生物钟相关调控规律已在畜禽生产领域得到了应用，其可用于改善动物的生长，提高动物性产品的质量㊂Ｔａｏ等［６１］的研究表明，生物钟基因在蛋鸭卵巢的表达水平与产蛋量密切相关㊂光刺激可通过影响生物钟基因的表达，提高肉仔鸡生长期体重和胸肌产量，改善饲料转化率［６２］㊂生物钟基因与奶山羊乳腺代谢密切相关，饲喂不同饲料可改变调生物钟基因表达，调控奶山羊的泌乳［６３］㊂畜禽骨骼肌中存在着生物钟基因，骨骼肌的生命活动受到生物钟基因的调控，ＰＧＣ－１α是连接生物钟和能量代谢的关键调控因子［６４］㊂研究表明，ＰＧＣ－１α在骨骼肌中的表达呈现明显的昼夜节律性，且ＰＧＣ－１α敲除小鼠在能量代谢方面出现异常的生理节律㊂ＰＧＣ－１α与生物钟基因形成反馈调节回路，首先ＰＧＣ－１α是生物时钟基因的上游调节因子，ＰＧＣ－１α能够诱导生物时钟关键基因的表达，如脑和肌肉芳香烃受体核转运样蛋白１基因（Ｂｍａｌ１）㊁时钟基因（Ｃｌｏｃｋ）和反向成红细胞增多症基因（Ｒｅｖ－ｅｒｂａ）等㊂此外，ＰＧＣ－１α还可以和视黄酸受体相关的孤儿受体（ＲＯＲα／γ）协同作用，使染色质的局部结构活化，从而激活Ｂｍａｌ１的转录［６５］㊂此外，ＳＩＲＴ１对ＰＧＣ－１α的去乙酰化是导致Ｂｍａｌ１激活的关键事件［６６］㊂其次，Ｃｌｏｃｋ１ａ：Ｂｍａｌ１ｂ复合体又能参与调控ＰＧＣ－１α的表达㊂在畜禽骨骼肌中生物钟基因与ＰＧＣ－１α共同调节骨骼肌的糖脂和能量代谢等生命活动，对于畜禽骨骼肌的生长发育具有重要的意义㊂当前缺乏ＰＧＣ－１α与生物钟基因联合作用调控畜禽肉品质的相关入研究，这可能会成为肉品领域新的研究方向㊂６　小结与展望综上所述，ＰＧＣ－１α作为一种多效转录调控因子，除参与调控肌肉脂肪生长发育及能量代谢外，还参与骨骼肌脂肪的沉积㊁肌纤维类型转化等生理活动，不仅能够在转录水平上调控骨骼肌能量代谢，而且还与生物钟基因相互作用反馈调节肌肉脂肪的生长发育㊂近年来随着我国人民水平的提高和饮食结构的改善，对于肉品质提出了更高的要求，例如肉品嫩度㊁多汁性和大理石花纹等，这些品质与肌纤维类型和肌内脂肪含量密切相关㊂如何生产肌纤维类型比例合适㊁肌内脂肪适中的肉品，是当前动物营养领域和肉品科学领域的研究热点㊂这与骨骼肌和脂肪生长代谢显著相关，且ＰＧＣ－１α在其中发挥了重要作用㊂尽管针对ＰＧＣ－１α调节骨骼肌生长发育㊁肌纤维类型转换㊁脂肪沉积㊁能量代谢的分子机制，已进行了大量的系统研究，也取得了一些重大进展，但还存在许多问题，诸如ＰＧＣ－１α如何精细调节肌内脂肪沉积，ＰＧＣ－１α调控肌纤维转换和能量代谢的详细信号通路，以及ＰＧＣ－１α与脂肪因子瘦素㊁脂联素㊁抵抗素等的相互激活转录机制，特别是如何通过有效地干预ＰＧＣ－１α调控肌肉脂肪沉积及靶向控制ＰＧＣ－１α介导肌纤维类型转换等㊂今后需对这些问题进行深入探索，以期通过ＰＧＣ－１α调控畜禽肌肉的生长发育㊁脂肪代谢㊁能量代谢等生理过程来提高肉品质㊂参考文献：［１］㊀ＭＩＴＲＡＲ，ＮＯＧＥＥＤＰ，ＺＥＣＨＮＥＲＪＦ，ｅｔａｌ．Ｔｈｅｔｒａｎｓｃｒｉｐｔｉｏｎａｌｃｏａｃｔｉｖａｔｏｒｓ，ＰＧＣ－１αａｎｄβ，ｃｏｏｐｅｒａｔｅｔｏｍａｉｎｔａｉｎｃａｒｄｉａｃｍｉｔｏ⁃ｃｈｏｎｄｒｉａｌｆｕｎｃｔｉｏｎｄｕｒｉｎｇｔｈｅｅａｒｌｙｓｔａｇｅｓｏｆｉｎｓｕｌｉｎｒｅｓｉｓｔａｎｃｅ［Ｊ］．ＪＭｏｌＣｅｌｌＣａｒｄｉｏｌ，２０１２，５２（３）：７０１－７１０．［２］㊀ＪＡＮＮＩＧＰＲ，ＤＵＭＥＳＩＣＰＡ，ＳＰＩＥＧＥＬＭＡＮＢＭ，ｅｔａｌ．Ｒｅｇｕｌａ⁃ｔｉｏｎａｎｄｂｉｏｌｏｇｙｏｆＰＧＣ－１α［Ｊ］．Ｃｅｌｌ，２０２２，１８５（８）：１４４４．［３］㊀ＥＳＴＥＲＢＡＵＥＲＨ，ＯＢＥＲＫＯＦＬＥＲＨ，ＫＲＥＭＰＬＥＲＦ，ｅｔａｌ．Ｈｕｍａｎｐｅｒｏｘｉｓｏｍｅｐｒｏｌｉｆｅｒａｔｏｒａｃｔｉｖａｔｅｄｒｅｃｅｐｔｏｒγｃｏａｃｔｉｖａｔｏｒ１（ＰＰＡＲＧＣ１）ｇｅｎｅ：ｃＤＮＡｓｅｑｕｅｎｃｅ，ｇｅｎｏｍｉｃｏｒｇａｎｉｚａｔｉｏｎ，ｃｈｒｏ⁃ｍｏｓｏｍａｌｌｏｃａｌｉｚａｔｉｏｎａｎｄｔｉｓｓｕｅｅｘｐｒｅｓｓｉｏｎ［Ｊ］．Ｇｅｎｏｍｉｃｓ，１９９９，６２（１）：９８－１０２．［４］㊀ＰＵＩＧＳＥＲＶＥＲＰ，ＲＨＥＥＪ，ＬＩＮＪ，ｅｔａｌ．Ｃｙｔｏｋｉｎｅｓｔｉｍｕｌａｔｉｏｎｏｆｅｎｅｒｇｙｅｘｐｅｎｄｉｔｕｒｅｔｈｒｏｕｇｈｐ３８ＭＡＰｋｉｎａｓｅａｃｔｉｖａｔｉｏｎｏｆＰＰＡＲγｃｏ⁃ａｃｔｉｖａｔｏｒ－１［Ｊ］．ＭｏｌＣｅｌｌ２００１，８：９７１－９８２．［５］㊀ＴＣＨＥＲＥＰＡＮＯＶＡＩ，ＰＵＩＧＳＥＲＶＥＲＰ，ＮＯＲＲＩＳＪＤ，ｅｔａｌ．Ｍｏｄｕ⁃ｌａｔｉｏｎｏｆｅｓｔｒｏｇｅｎｒｅｃｅｐｔｏｒ－αｔｒａｎｓｃｒｉｐｔｉｏｎａｌａｃｔｉｖｉｔｙｂｙｔｈｅｃｏａｃｔｉｖａｔｏｒＰＧＣ－１［Ｊ］．ＢｉｏｌＣｈｅｍ，２０００，２７５（２１）：１６３０２－１６３０８．㊀［６］㊀ＢＨＡＬＬＡＳ，ＯＺＡＬＰＣ，ＦＡＮＧＳ，ｅｔａｌ．Ｌｉｇａｎｄ－ａｃｔｉｖａｔｅｄｐｒｅｇｎａｎｅＸｒｅｃｅｐｔｏｒｉｎｔｅｒｆｅｒｅｓｗｉｔｈｈｎｆ－４ｓｉｇｎａｌｉｎｇｂｙｔａｒｇｅｔｉｎｇａｃｏｍｍｏｎｃｏ⁃ａｃｔｉｖａｔｏｒＰＧＣ－１α：ｆｕｎｃｔｉｏｎａｌｉｍｐｌｉｃａｔｉｏｎｓｉｎｈｅｐａｔｉｃｃｈｏｌｅｓｔｅｒｏｌａｎｄｇｌｕｃｏｓｅｍｅｔａｂｏｌｉｓｍ［Ｊ］．ＢｉｏｌＣｈｅｍ，２００４，２７９（４３）：４５１３９－４５１４７．㊀［７］㊀ＲＨＥＥＪ，ＩＮＯＵＥＹ，ＹＯＯＮＪＣ，ｅｔａｌ．ＲｅｇｕｌａｔｉｏｎｏｆｈｅｐａｔｉｃｆａｓｔｉｎｇｒｅｓｐｏｎｓｅｂｙＰＰＡＲγｃｏａｃｔｉｖａｔｏｒ－１α（ＰＧＣ－１α）：ｒｅｑｕｉｒｅｍｅｎｔｆｏｒｈｅｐａｔｏｃｙｔｅｎｕｃｌｅａｒｆａｃｔｏｒ４αｉｎｇｌｕｃｏｎｅｏｇｅｎｅｓｉｓ［Ｊ］．ＰｒｏｃＮａｔｌＡｃａｄＳｃｉＵＳＡ，２００３，１００（７）：４０１２－４０１７．［８］㊀马燕．藏羚羊和藏系绵羊ＰＧＣ－１α基因编码区的克隆与分析［Ｄ］．西宁：青海大学，２０１２．［９］㊀张林．超表达猪源ＰＧＣ－１α促进小鼠和猪肌纤维类型转变的研究［Ｄ］．武汉：华中农业大学，２０１４．［１０］ＲＯＤＧＥＲＳＪＴ，ＬＥＲＩＮＣ，ＨＡＡＳＷ，ｅｔａｌ．Ｎｕｔｒｉｅｎｔｃｏｎｔｒｏｌｏｆｇｌｕ⁃ｃｏｓｅｈｏｍｅｏｓｔａｓｉｓｔｈｒｏｕｇｈａｃｏｍｐｌｅｘｏｆＰＧＣ－１αａｎｄＳＩＲＴ１［Ｊ］．Ｎａｔｕｒｅ，２００５，４３４（７０２９）：１１３－１１８．［１１］ＷＡＮＧＷ，ＷＵＤ，ＤＩＮＧＪ，ｅｔａｌ．Ｍｏｄｉｆｉｅｄｒｏｕｇａｎｄｅｃｏｃｔｉｏｎａｔｔｅｎ⁃ｕａｔｅｓｈｅｐａｔｏｃｙｔｅａｐｏｐｔｏｓｉｓｔｈｒｏｕｇｈａｍｅｌｉｏｒａｔｉｎｇｍｉｔｏｃｈｏｎｄｒｉａｌｄｙｓ⁃ｆｕｎｃｔｉｏｎｂｙｕｐｒｅｇｕｌａｔｅｄＳＩＲＴ１／ＰＧＣ－１αｓｉｇｎａｌｉｎｇｐａｔｈｗａｙ［Ｊ］．ＰｏｕｌｔＳｃｉ，２０２３，１０２（１０）：１－１９．［１２］ＬＥＲＩＮＣ，ＲＯＤＧＥＲＳＪＴ，ＫＡＬＵＭＥＤＥ，ｅｔａｌ．ＧＣＮ５ａｃｅｔｙｌｒａｎｓ⁃ｆｅｒａｓｅｃｏｍｐｌｅｘｃｏｎｔｒｏｌｓｇｌｕｃｏｓｅｍｅｔａｂｏｌｉｓｍｔｈｒｏｕｇｈｔｒａｎｓｃｒｉｐｔｉｏｎａｌｒｅｐｒｅｓｓｉｏｎｏｆＰＧＣ－１α［Ｊ］．ＣｅｌｌＭｅｔａｂ，２００６，３（６）：４２９－４３８．［１３］ＹＥＦ，ＷＵＬ，ＬＩＨ，ｅｔａｌ．ＳＩＲＴ１／ＰＧＣ－１αｉｓｉｎｖｏｌｖｅｄｉｎａｒｓｅｎｉｃ－ｉｎｄｕｃｅｄｍａｌｅｒｅｐｒｏｄｕｃｔｉｖｅｄａｍａｇｅｔｈｒｏｕｇｈｍｉｔｏｃｈｏｎｄｒｉａｌｄｙｓｆｕｎｃｔｉｏｎ，ｗｈｉｃｈｉｓｂｌｏｃｋｅｄｂｙｔｈｅａｎｔｉｏｘｉｄａｔｉｖｅｅｆｆｅｃｔｏｆｚｉｎｃ［Ｊ］．ＥｎｖｉｒｏｎＰｏｌｌｕｔ，２０２３，３２０：１２１０８４－１２１０８６．［１４］ＮＥＴＯＩＶＳ，ＰＩＮＴＯＡＰ，ＭＵＮＯＺＶＲ，ｅｔａｌ．Ｐｌｅｉｏｔｒｏｐｉｃａｎｄｍｕｌｔｉ－ｓｙｓｔｅｍｉｃａｃｔｉｏｎｓｏｆｐｈｙｓｉｃａｌｅｘｅｒｃｉｓｅｏｎＰＧＣ－１αｓｉｇｎａｌｉｎｇｄｕｒｉｎｇｔｈｅａｇｉｎｇｐｒｏｃｅｓｓ［Ｊ］．ＡｇｅｉｎｇＲｅｓＲｅｖ，２０２３，８７：１０１９３５－１０１９５４．㊀［１５］ＰＵＩＧＳＥＲＶＥＲＰ，ＷＵＺ，ＰＡＲＫＣＷ，ｅｔａｌ．Ａｃｏｌｄ－ｉｎｄｕｃｉｂｌｅｃｏ⁃ａｃｔｉｖａｔｏｒｏｆｎｕｃｌｅａｒｒｅｃｅｐｔｏｒｓｌｉｎｋｅｄｔｏａｄａｐｔｉｖｅｔｈｅｒｍｏｇｅｎｅｓｉｓ［Ｊ］．Ｃｅｌｌ，１９９８，９２（６）：８２９－３９．［１６］ＬＩＬ，ＬＵＺ，ＷＡＮＧＹ，ｅｔａｌ．Ｇｅｎｉｓｔｅｉｎａｌｌｅｖｉａｔｅｓｃｈｒｏｎｉｃｈｅａｔｓｔｒｅｓｓ－ｉｎｄｕｃｅｄｌｉｐｉｄｍｅｔａｂｏｌｉｓｍｄｉｓｏｒｄｅｒａｎｄｍｉｔｏｃｈｏｎｄｒｉａｌｅｎｅｒｇｅｔｉｃｄｙｓ⁃ｆｕｎｃｔｉｏｎｂｙａｃｔｉｖａｔｉｎｇｔｈｅＧＰＲ３０－ＡＭＰＫ－ＰＧＣ－１αｓｉｇｎａｌｉｎｇｐａｔｈ⁃ｗａｙｓｉｎｔｈｅｌｉｖｅｒｓｏｆｂｒｏｉｌｅｒｃｈｉｃｋｅｎｓ［Ｊ］．ＰｏｕｌｔＳｃｉ，２０２３，１０３（１）：１－１２．［１７］ＧＡＲＮＩＥＲＡ，ＦＯＲＴＩＮＤ，ＺＯＬＬＪ，ｅｔａｌ．Ｃｏｏｒｄｉｎａｔｅｄｃｈａｎｇｅｓｉｎ。

富士康英语笔试题及答案一、词汇题（每题1分，共10分）1. The company has a large number of _______ employees.A. permanentB. temporaryC. casualD. part-time答案： A2. The _______ of the new product was a great success.A. introductionB. innovationC. initiationD. induction答案： A3. The _______ of the meeting has been postponed due to bad weather.A. commencementB. completionC. cancellationD. termination答案： A4. She has a _______ knowledge of the subject.A. superficialB. profoundC. elementaryD. rudimentary答案： B5. The _______ of the old building was a difficult task.A. renovationB. demolitionC. constructionD. destruction答案： B6. The _______ of the company's profits has been steady over the past decade.A. fluctuationB. stabilityC. increaseD. decrease答案： B7. The _______ of the new policy was met with mixed reactions.A. implementationB. enforcementC. initiationD. establishment答案： A8. The _______ of the project was completed on schedule.A. executionB. performanceC. operationD. function答案： A9. The _______ of the company's assets is a complex process.A. evaluationB. valuationC. assessmentD. estimation答案： B10. The _______ of the new CEO was announced at the annual meeting.A. appointmentB. nominationC. electionD. designation答案： A二、阅读理解题（每题2分，共20分）Passage 1In recent years, the rise of e-commerce has significantly impacted the retail industry. Traditional brick-and-mortar stores are facing challenges as online shopping becomes more popular. However, some companies have adapted to thesechanges by integrating their online and offline presence to create a seamless shopping experience for customers.Questions:11. What has been the impact of e-commerce on the retail industry?A. It has led to the decline of online shopping.B. It has caused an increase in the popularity ofphysical stores.C. It has significantly impacted the way people shop.D. It has resulted in the closure of all physical stores.答案： C12. How have some companies adapted to the rise of e-commerce?A. By closing their physical stores.B. By focusing solely on online sales.C. By integrating their online and offline presence.D. By ignoring the changes in consumer behavior.答案： CPassage 2The development of renewable energy sources is crucial for reducing our reliance on fossil fuels and combating climatechange. Solar and wind power are two of the most promising renewable energy sources, offering clean and sustainable alternatives to traditional energy production methods.Questions:13. Why is the development of renewable energy sources important?A. To increase our reliance on fossil fuels.B. To reduce the cost of energy production.C. To combat climate change and reduce reliance on fossil fuels.D. To make energy production more difficult.答案： C14. Which two renewable energy sources are mentioned in the passage?A. Solar and nuclear power.B. Wind and hydro power.C. Solar and wind power.D. Fossil fuels and hydro power.答案： C三、完形填空题（每题1.5分，共15分）In the modern world, technology plays a vital role in our daily lives. It has transformed the way we communicate, work, and learn. However, with the rapid advancement of technology, there are also concerns about its impact on society.15. Technology has made our lives _______ easier.A. muchB. littleC. notD. no答案： A16. The _______ of technology is not without its drawbacks.A. progressB. developmentC. advancementD. growth答案： C17. People are increasingly _______ about the effects of technology on privacy.A. concernedB. informedC. interestedD. curious答案： A18. Despite。

王旭，李聪，张万刚，等. 脂肪对不同熟化温度下乳化肠挥发性成分的影响[J]. 食品工业科技，2023，44（24）：43−53. doi:10.13386/j.issn1002-0306.2022120177WANG Xu, LI Cong, ZHANG Wangang, et al. Effects of Fat on Volatile Components of Emulsified Sausage at Different Cooking Temperatures[J]. Science and Technology of Food Industry, 2023, 44(24): 43−53. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2022120177· 研究与探讨 ·脂肪对不同熟化温度下乳化肠挥发性成分的影响王　旭1，李　聪2，张万刚1，王　颖2，徐宝才1,2,*（1.南京农业大学食品科技学院，江苏南京 210095；2.合肥工业大学食品与生物工程学院，安徽合肥 230009）摘　要：为明确脂肪对不同熟化温度下（80 ℃，30 min 、90 ℃，30 min 、100 ℃，30 min 和121 ℃，20 min ）猪肉乳化香肠挥发性物质的影响，采用感官评价、电子鼻（Electronic nose ，E-nose ）和固相微萃取-气相色谱质谱联用技术（Solid-phase microextraction coupled-gas chromatography-mass spectrometry ，SPME-GC-MS ）对添加或不添加脂肪的乳化肠在不同熟化温度下挥发性物质进行分析。

结果表明，添加脂肪的乳化肠，熟化条件为100 ℃，30 min 的样品风味最好，添加脂肪可提高乳化肠脂香味、硫磺味、哈喇味和青草味的感官强度，抑制高温乳化肠肉香味和蘑菇味的感官强度；电子鼻能有效区分添加脂肪或不添加脂肪的样品，但80 ℃，30 min 组的样品无法有效区分；添加脂肪的样品中，除100 ℃，30 min 组和121 ℃，20 min 组外，电子鼻能很好的将不同熟化温度的样品区分开。

肥胖原因的英语作文In today's fast-paced world, obesity has become a growing concern affecting people of all ages. The reasons behind this epidemic are multifaceted and complex. Here is an essay that delves into the causes of obesity:The Rising Tide of Obesity: Unraveling the CausesObesity, a condition characterized by excessive body fat, has been on the rise globally. The World Health Organization (WHO) reports that obesity has nearly tripled since 1975, making it a significant public health issue. Several factors contribute to this alarming trend, and understanding them is crucial for developing effective prevention and intervention strategies.1. Unhealthy DietOne of the primary reasons for the increase in obesity is the shift towards unhealthy diets. The availability andaffordability of high-calorie, nutrient-poor foods have madeit easier for individuals to consume more calories than they burn. Fast food, sugary beverages, and processed snacks are often the culprits, as they are rich in fats, sugars, andsalts but lack essential nutrients.2. Sedentary LifestyleModern lifestyles have become increasingly sedentary. With the advent of technology, physical activity has been replaced by screen time. Office jobs, long commutes, and leisure activities that involve watching television or playing video games contribute to a lack of exercise. This sedentary behavior leads to a decrease in energy expenditure, which can result in weight gain.3. Genetic PredispositionResearch has shown that genetics play a role in the development of obesity. Certain genes may predispose individuals to gain weight more easily or affect their metabolism. While genetic factors cannot be changed, understanding one's genetic risk can help in making informed lifestyle choices.4. Psychological FactorsEmotional eating is another factor that contributes to obesity. Stress, depression, and other psychological issues can lead to overeating as a coping mechanism. Comfort foods, often high in calories, are sought after during times of emotional distress, leading to weight gain.5. Socioeconomic StatusThere is a correlation between socioeconomic status and obesity. Lower-income individuals may have limited access to healthy food options and safe spaces for physical activity.Additionally, they may face barriers such as time constraints and lack of resources, which can hinder their ability to maintain a healthy lifestyle.6. Environmental FactorsThe environment in which we live also influences our eating habits and physical activity levels. Urban sprawl, lack of green spaces, and poor public transportation systems can make it difficult for individuals to engage in regular physical activity. Furthermore, aggressive marketing of unhealthy foods can lead to increased consumption.ConclusionAddressing the obesity epidemic requires a multifaceted approach that considers the various contributing factors. It is essential to promote healthy eating habits, encourage regular physical activity, and create supportive environments that facilitate these behaviors. By understanding the causes of obesity, we can work towards developing strategies to combat this global health issue.This essay provides a comprehensive overview of the causes of obesity, highlighting the importance of a holistic approach to tackle this complex health challenge.。

黄璐，任雨晴，赵迪，等. 植物基脂肪模拟物对肉制品质量影响及应用研究进展[J]. 食品工业科技，2023，44（8）：461−468. doi:10.13386/j.issn1002-0306.2022060305HUANG Lu, REN Yuqing, ZHAO Di, et al. Research Progress on the Effect of Plant-based Fat Simulants on Meat Product Quality and Application[J]. Science and Technology of Food Industry, 2023, 44(8): 461−468. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2022060305· 专题综述 ·植物基脂肪模拟物对肉制品质量影响及应用研究进展黄　璐1，任雨晴1，赵　迪1，曹金诺2，李　赫1, *，刘新旗1（1.北京工商大学食品与健康学院，国家大豆加工产业技术创新中心，北京 100048；2.植物肉（杭州）健康科技有限公司，浙江杭州 310000）摘　要：为满足消费者对健康饮食的要求和未来食品供应的可持续性，植物基肉类替代品被广泛开发，具有广阔的市场发展前景。

用植物基复合脂肪模拟物代替肉制品中的脂肪，可以减少食物中的脂肪，对消费者的健康有益。

本文主要综述了各种胶体对植物基复合脂肪模拟物性质的影响，以便为其在肉制品行业中的应用提供更多的理论支持。

多糖类胶体的添加可以提高脂肪模拟物的持水能力，增加肉制品的多汁感；蛋白类胶体可以提高脂肪模拟物的营养特性和弹性，增强咀嚼感和产品质地。

此外，通过整理近年来国内外对植物基脂肪模拟物的研究，对植物基脂肪模拟物在肉制品的应用进行了分类和较全面的总结，并基于此阐述了植物基脂肪模拟物对肉制品质量的影响。

为何肥胖能致癌英语作文Title: The Link Between Obesity and Cancer。

Obesity, a growing epidemic worldwide, has beenidentified as a significant risk factor for various health conditions, including cancer. This essay aims to explorethe intricate relationship between obesity and cancer, shedding light on the underlying mechanisms andimplications for public health.To begin with, it's crucial to understand thedefinition of obesity. Obesity is characterized by anexcess accumulation of body fat, typically resulting from a combination of genetic, environmental, and behavioral factors. In recent years, the prevalence of obesity has reached alarming levels, posing a considerable burden on healthcare systems globally.One of the primary ways in which obesity contributes to cancer risk is through chronic inflammation. Adipose tissue,or fat cells, secretes various inflammatory molecules known as adipokines. When excess fat accumulates in the body, these adipokines are released in higher amounts, leading to a state of chronic low-grade inflammation. This persistent inflammatory environment creates a favorable milieu for the development and progression of cancer.Moreover, obesity is closely linked to insulin resistance and hyperinsulinemia, conditions characterized by impaired insulin function and elevated insulin levels, respectively. Insulin is a hormone responsible for regulating blood sugar levels, but it also promotes cell growth and proliferation. Elevated insulin levels, as seen in obese individuals, can stimulate the proliferation of cancer cells and inhibit apoptosis, or programmed cell death, thereby fostering tumor growth.Furthermore, adipose tissue serves as an endocrine organ, producing hormones such as estrogen and leptin, which can influence cancer risk. In postmenopausal women, adipose tissue becomes the primary source of estrogen production. Higher levels of estrogen have been associatedwith an increased risk of breast and endometrial cancer. Similarly, leptin, a hormone involved in regulating appetite and metabolism, has been implicated in promoting cancer cell survival and proliferation.In addition to these biological mechanisms, obesity is also associated with several lifestyle factors that can contribute to cancer risk. For instance, obese individuals are more likely to have a sedentary lifestyle and consume a diet high in processed foods and sugar, both of which are linked to cancer development. Furthermore, obesity is often accompanied by comorbidities such as type 2 diabetes and cardiovascular disease, which themselves are associated with an increased risk of certain cancers.The implications of the obesity-cancer link are profound for public health policies and interventions. Efforts to combat obesity must be multifaceted, addressing not only individual behaviors but also societal and environmental factors. Strategies aimed at promoting healthy eating habits, increasing physical activity, and reducing sedentary behavior are essential in reducingobesity prevalence and mitigating cancer risk.Moreover, healthcare providers play a critical role in the prevention and management of obesity-related cancer. Screening programs can help identify individuals at higher risk due to obesity and implement early interventions to prevent cancer development. Additionally, healthcare professionals should emphasize the importance of weight management and healthy lifestyle choices in cancer prevention during patient consultations.In conclusion, obesity represents a significant modifiable risk factor for cancer, exerting its influence through various biological, hormonal, and behavioral mechanisms. Understanding the complex interplay between obesity and cancer is essential for developing effective prevention and intervention strategies. By addressing the root causes of obesity and promoting healthy lifestyles, we can mitigate the burden of obesity-related cancers and improve public health outcomes globally.。

高温条件下CaCO3 对炉渣流动特性的影响摘要通过添加不同量的CaCO3来对选定的煤灰进行试验，以理解对包括煤灰熔点、炉渣粘度、临界粘度时的温度和炉渣类型等流动特性的影响。

我们应用了ICP-AES、XRD 和FTIR 的分析方法来确定炉渣的成分和结构。

我们还应用了化学热力学软件Factsage 来计算SiO2 —Al2O3 —CaO—FeO 系统的液相温度并预测会形成的矿物质以及固相的比例作为温度的函数。

结果表明，由化学热力学软件Factsage 计算出的液相线温度能很好地预测煤灰熔点温度的变化。

炉渣粘度会随着添加的CaCO3 的量的变化而增加，这是因为固相的形成过程不同。

傅里叶变换红外(FTIR) 光谱表明，Ca2 + 会导致将聚合的Si — O — Si 破坏成Si-O的结构，所以子炉渣中增加Ca2 + 中会导致高于液相线温度的粘度降低，当低于液相线温度时，固形物含量会随着在临界粘度(Tcv) 温度以上的CaCO3 的增加而减少。

同时，我们发现固体颗粒形成的速率与Tcv相关并基于此发现提出了新的预测Tcv的方法。

此外，利用x射线衍射分析推测出了炉渣的类型与添加CaCO3 的量有关。

我们希望对煤灰熔融温度、Tcv 和炉渣类型的预测来作为对于适合排渣气化技术的添加助熔剂以规范煤灰特性的参考。

关键词CaCO3;煤灰融化温度;炉渣粘度;临界粘度温度;炉渣类型1.引言对未来电力发电和化工生产的高效率的需求导致了对IGCC 技术的关注度的增加，特别是在先进的煤气化技术例如气流床气化炉等。

在气化炉中，在高于1400° C的高温度下和强气流的作用下，煤中的有机物质会在短时间内完全燃烧并气化，并且煤中的矿物质会变成煤灰。

煤灰会变成液体炉渣是由于在高温下其组分中的矿物质融化并相互反应的结果。

对于带有液态炉渣去除过程的气流床气化炉而言，炉渣流动特性比煤中的有机质的转换更为重要。

连续排渣对于不同气流的气化炉的成功操作非常重要（GE、Shell、Prenfflol、GSP、Texco、Eagle等不同的品牌的气化炉），所以在高温下炉渣的流动性能以及添加剂对他们的影响具有非常重要的意义。

10Fats and Oils in Feedstuffs and Pet FoodsEdmund E.Lusas and Mian N.Riaz Fats and oils are used for many purposes in animal feeds and pet foods,including the following:Increasing caloric density of feeds(by about2.25times that of similar dry weights of proteins or carbohydrates).Improving feed palatability and appearance.Reducing total feed intake,increasing feed efficiency,and minimizing feed costs.Increasing blood glycogen levels and endurance in working animals like horses and sled dogs.Lowering the heat of reaction during digestion and metabolism—important for comfort and productivity of large animals in hot weather.Delaying digestion of feedstuffs beyond the rumen by use of inert forms of fats and coatings.Providing needed molecular structures through dietary essential fatty acids (EFA)and phospholipids.Improving appearance of skin and hair,and prevention of dermatitis.Modifying fatty acid profiles in‘‘designer food’’animal products.Bailey’s Industrial Oil and Fat Products,Sixth Edition,Six V olume Set.Edited by Fereidoon Shahidi.Copyright#2005John Wiley&Sons,Inc.317318FATS AND OILS IN FEEDSTUFFS AND PET FOODSCarrying fat-soluble vitamins and color compounds.Binding heat-sensitiveflavorings,vitamins,medications,and‘‘instant gravy’’mixes to pet foods and feeds after extrusion or drying.Improving dispersion of dry mixes,e.g.,lecithin in calf milk replacers.Preventing segregation of mixed feeds.Reducing dustiness of feeds and feeding operations and of grain elevator dust.Lubricating feed processing machinery.Nutritional values of fats and oils differ with fatty acid composition,with the species,age,physiological stage,environment of the animal,and adequacy of the overall diet.Care should be exercised in regard to the following: Avoid overtaxing the fat-handling capabilities of digestion systems of the respective species,especially young animals and ruminants.Avoid contamination of fats,oils,and oil-bearing materials with toxic or unwholesome constituents.Handle oil-bearing feedstuffs with active antinutritional or toxic constituents, including mycotoxins,properly and legally.Avoid excessive levels of fat that interfere with making cohesive pellets(more than4%)or restrict the desired puffing of starches and development of lamellar soy protein textures(more than6%)in extruded feeds.Edible animal fat in the United States can be rendered only in food grade plants under inspection of the U.S.Department of Agriculture(USDA)(1).The majority of tallows and greases used domestically in animal feeds and pet foods are feed grade.The National Renderer’s Association(NRA)describes rendering as a process thatheats raw animal by-products to release fat(71.1–82.2 C;160–180 F)and remove moisture(115.6–126.7 C;240–280 F).Ninety percent of the fat is removed from the protein by presses,leaving approximately10%in the protein meal.Fat quality is determined by hardness,color,moisture,impurities,stability,and free fatty acids (FFA)content.In the United States,inedible fats are called tallows if,after saponification in the American Oil Chemists’Society’s titer test(AOCS Cc12-59),solidification occurs above40 C(104 F),and greases if solidification occurs below this temperature(1). The demarcation temperature varies among countries and38 C(100.4 F)is used by some.Throughout this chapter,the term tallow refers to both tallows and greases, which also may contain vegetable oils,recycled by renderers.Fat and oil usually refer to semisolid and liquid forms of triacylglycerols(trigly-cerides),respectively,although the use of these terms is not consistent throughout industry.In this chapter,the term fats means the group of commercial lipids(mono-, di-and triacylglycerols,fatty acids,and phospholipids),whether in solid or liquidHISTORY319 state.In endorsement of the movement to improve the value of by-products of var-ious agribusiness operations,the term coproduct is used throughout this chapter, except where established regulations are being quoted.Individuals who are not fats’and oils’chemists may benefit from the following orientation.Polyunsaturated fatty acids is abbreviated as PUFA.Essential fatty acids(EFA)are required by the host animal but are not synthesized and are avail-able only through the diet.The notation C18indicates a fatty acid chain,18carbons long.C18:0and C18:3identify the number of unsaturated(‘‘double’’)bonds.C18:0 represents a completely saturated fatty acid,18carbons long,in this case,stearic acid.C18:3represents a fatty acid,18carbons long and with3unsaturated sites,but does not indicate the location of the double bonds.Linolenic acid(9,12,15-octadecatrienoic acid;IUPAC convention)is also 9,12,15-C18:3,meaning an18-carbon fatty acid with double bonds occurring after the9,12,and15carbons counted from the carboxyl end of the chain;this is the major linolenic acid isomer and also is called a-linolenic acid.Another C18:3fatty acid that has received considerable interest from nutritionists in recent years is 6,9,12-octadecatrienoic acid(g-linolenic acid),actually a reduced member of the linoleic family.The symbolÁhas been retained from the Geneva naming conven-tion for limited use here.For example,aÁ5desaturase enzyme installs a double bond after thefifth carbon,counting the carboxyl carbon as number one.When working with polyunsaturated fatty acids,sometimes it is more convenient to count from the methyl end.The terms omega(o)and n are sometimes used for this pur-pose.The notation C18:2n-6signifies linolenic acid,an18-carbon chain fatty acid with two unsaturated positions,thefirst one occurring after the sixth carbon atom counting from the methyl end.(Linolenic acid is represented by C18:2n-3.) Throughout this chapter,the all-cis forms of fatty acids are intended unless identi-fied otherwise.1.HISTORY1.1.Evolution of UsesOccasional feeding trials of extracted fats and oils to animals have been reported in the United States since about the1890s when thefirst state agricultural experiment stations were established.However,significant quantities did not become available at prices affordable for volume feeding until the late1940s.Feeding applications in the1950s and1960s focused on high energy broiler rations and on improving palat-ability of dry pet foods.Research on feeding fats and oils to swine and ruminants grew rapidly in the1970s and1980s,and was extended to aquaculture species in recent years.1.2.Demands for Better Feeds and FoodsImprovements in genetics and biotechnology manipulations of metabolic systems, including feeding of growth-stimulating hormones(bovine somatotropin,BST,and320FATS AND OILS IN FEEDSTUFFS AND PET FOODSporcine somatotropin,PST),have developed animals with increased capabilities for producing milk and meat.Increasing the caloric and amino acid intakes to realize these abilities are difficult with traditional feedstuffs,and calorie-dense and nutri-tionally balanced feedstuffs are increasingly sought.Concerns by the public about the amounts and types of fats in the human diet have led to increased demands for poultry,fish,and leaner red meats.The latter need is being met by hand and mechanical trimming until animal genetics and feed-ing practices are developed to produce lean animals directly.Various snack and convenience food manufacturers,and fast food shops,have changed from frying in tallow to frying in vegetable oils.Currently,rendered animal fats and inedible recycled tallows are in surplus in the affluent countries and are sold at prices that place them among the lower cost sources of concentrated metabolizable energy for feed uses.The types of fat fed affect the fatty acid composition of animal tissues(meat) and products(milk and eggs)as well as the fat metabolism in consumers of these products.This has led to the‘‘designer foods’’concept—animal products with fat compositions intentionally altered by feeding for human health benefits(2). Although nutritionists are not fully in agreement on optimum fatty acids profiles, designer eggs with increased contents of linolenic and other n-3PUFA fatty acids are being marketed.The question of which fats or fractions are suitable for achiev-ing the desired designer foods is materializing and may dominate feeds applications research for the next decade or longer.1.3.Feeding of Whole OilseedsOilseed producers have recognized that it may be more profitable to process and feed whole oilseeds on the farm,rather than sell them into the elevator–oil mill–refinery infrastructure and purchase extracted protein meals,tallows,and spent res-taurant yellow greases(mixtures of animal fats and vegetable oils).Technologies have been developed to minimize the effects of natural toxic and growth-inhibitor components in raw cottonseed,soybeans,and canola seed.Feed processors and livestock feeders can now switch between using in-seed and extracted fats and oils,depending on price.Both options must be considered in a comprehensive review of feeding fats.RMATION SOURCES,AUTHORITIES,AND OBLIGATIONS2.1.Early Technology TransferThe modern feeding of commercial animals and pets has become a quantifiable, information-based science with alternative choices and accompanying responsi-bilities.The exploration and codifying of animal nutritional requirements and feed-stuff nutrient compositions have long been ongoing processes.Major contributions to transferring knowledge have been made by the22editions of Feeds and Feeding, published from1898to1956(by W.A.Henry and later by F.B.Morrison).ThisINFORMATION SOURCES,AUTHORITIES,AND OBLIGATIONS321 bible was succeeded in1978by Feeds and Nutrition—Complete(3).Updated infor-mation is published in the more compact Feeds and Nutrition Digest(4).Other feeding and feedstuffs reference books also have been published during the years (5,6).The newer editions of books on feedstuffs and feeding management are more guarded in generalized statements about nutrients metabolism than publications of a decade ago.This is probably because different metabolic pathways are being found between species as well as alternative pathways within the same species.2.2.National Research Council Nutrient RequirementsThe developing knowledge about nutrient requirements of different species in various life stages has been monitored,interpreted,and summarized by expert sub-committees of the Committee on Animal Nutrition of the Board on Agriculture of the National Research Council(NCR).Various editions of Nutrient Requirements are currently available for beef cattle(7),cats(8),dairy cattle(9),dogs(10),fish (11),goats(12),horses(13),mink and foxes(14),nonhuman primates(15),poultry (16),rabbits(17),sheep(18),and swine(19).Each publication contains recommen-dations for various life stages of the respective species,a literature review and bibliography of feeding trials,and tables of ingredients commonly fed to that spe-cies.Respective nutrients composition,digestibility,and metabolizable energy values are available in the more recent editions.Gradually,the older general nutri-ents composition references,including the United States–Canadian Tables of Feed Composition(20),are being replaced by species-specific information.Some of the recent Nutrient Requirements publications,notably for dairy cattle (8)and horses(13),include computer discs with interactive programs for calculat-ing nutrients requirements based on age,weight,sex,physiological stage,and work or performance of the animal.Various compendiums of feedstuff compositions and animal requirements,based on NRC publications,are published periodically,in-cluding the annual Feedstuffs Reference Issue.2.3.Association of American Feed Control Officials Regulations NRC nutrient requirements are advisory and have no regulatory status.The Asso-ciation of American Feed Control Officers(AAFCO)establishes the official defini-tions and names of feed ingredients,nutritional and labeling requirements for dog and cat foods,regulations on medicated feeds,labeling practices,and other require-ments for selling feeds.AAFCO official ingredient names must be shown in listings on the product package,tag,or delivery invoice,in order of diminishing content for fixed(‘‘closed’’)formula products and percentage-wise for open formula mixed feeds.Uniform regulations have been developed to expedite interstate commerce in feedstuffs,but each state also has reserved the right to establish independent regulations and interpretations.All commercial feedstuffs must be registered directly with the feed control official in each state where sold.AAFCO definitions and regulations are updated and published annually in the Official Publication. Copies can be obtained by contacting local feed control officials.322FATS AND OILS IN FEEDSTUFFS AND PET FOODSIngredients and regulations continuously evolve.For example,the1994Official Publication includes thefirst listing and temporary status of feed grade‘‘hydro-lyzed sucrose polyesters’’;these are nutrient-containing coproducts from the man-ufacture of low calorie fat substitutes.The establishment of an ingredient definition in the Official Publication is not an endorsement of its efficacy for specific nutri-tional objectives,but rather affirmation of its general safety under the conditions of intended use within the scope of current expert knowledge.2.4.International Feed,AAFCO Ingredients,and FDA Numbers Ingredients in NRC publications are identified by their international feed numbers (IFN)and names,currently developed and maintained by the Feed Composition Data Bank(FCDB)at the National Agricultural Library in Beltsville,Maryland. Ingredient definitions in the Official Publication use AAFCO numbers and also include the IFN.Several different IFN specifications and commercial quality trading grades for a similar material may qualify under the same AAFCO name. Some AAFCO ingredients(essentially isolated chemicals)also carry FDA identity numbers under the Food Additives Amendment of the Code of Federal Regulations (21CFR).2.5.Formulating Feeds for Minimum Ingredients CostsThe published tables of animal nutrient requirements and feedstuffs composition are crude approximations across the industry at best.A formulator usually will be more effective if he or she applies local experience in feeding animals of similar genetic origin under the environmental conditions at hand and relies on actual analyses of the ingredients received or the historical performance of the specific supplier—if such information is available.Modern techniques for measuring metabolism and instrumental analysis have enabled rapid estimations of animal needs and nutrient availability in specific feed-stuffs.Uniformity in feedstuffs,despite origin,is being advanced by global trade, harmonization of product definitions,and trading standards and by total quality management(TQM)programs like the ISO9000movement in Europe.The avail-ability and decreasing costs of desktop and notebook computers in the last decade has made the calculation of least-cost feed formulas by linear programming avail-able to many feed formulators.These factors,coupled with instantaneous knowl-edge of costs and availability of alternative feedstuffs,regionally and globally, through on-line communication networks are rapidly exhausting the undiscovered bargains in feedstuffs.In the future,profits in animal feeding are increasingly likely to result from private knowledge about(1)responses of animals with known genetic abilities,(2)ensuring animal health and comfort in extreme climates and weather conditions,and(3)improved effectiveness in feeding management practices.Claims of improved feed conversion abilities and improved health status already are being made for genetically controlled broilers and puter programs are now able to formulate feeds at least cost on the basis of digestible,metabolizable,orAVAILABILITY,CHARACTERISTICS,AND COMPOSITION323 net energy,protein,crudefiber,ash,essential amino acids,and specific vitamins and minerals for different growth stages of selected species.Formulas also may be flexed for specific EFA and triacylglycerol structures in the future.2.6.Consequences of Feedstuffs ContaminationThe consolidation of feeds processing and rendering into fewer but bigger installa-tions has also set up the conditions for large and widespread economic losses when mistakes or accidents occur.One example is the chick edema and death problems in the early to mid1970s that were traced to feeding fats and fatty acids contaminated with polychlorodibenzo-p-dioxins(21,22)and polychlorophenols(23)possibly of herbicide origin.This led to purchase specifications that tallows be guaranteed free of chick edema factors by renderers or distributors.Another example is the3-year outbreak of polybrominated biphenyls(PBB) poisoning that occurred in Michigan during1973–1976from a one-time acci-dental mislabeling of a toxicfire retardant and its inclusion in an animal feed con-centrate mix.An unknown quantity of meat,dairy products,and rendered materials entered the food and recycling chains before the problem was recognized and the involved farms quarantined.By1978,an estimated8million of Michigan’s 9.1million residents had detectable levels of PBB in their bodies(24).Later studies continued tofind PBB in samples of serum,body fat,and breast milks of most Michigan residents(25).Finally,dairy cows fed whole cottonseed that contains aflatoxins,at levels higher than the20ppb permitted by FDA,can transfer them to milk in amounts greater than the0.5m m g/kg FDA action level(26).State and national programs for monitoring aflatoxin content in milk have been implemented as the feeding of whole cottonseed to cattle has increased and expanded to states not producing cotton.Even nontoxic substances like polyethylene packaging materials,which melt at rendering temperatures can cause nuisance problems by solidifying at 80 C and forming lumps that clog fat application spray nozzles(27).3.AVAILABILITY,CHARACTERISTICS,AND COMPOSITION3.1.Supply and Uses of Feeding FatsStability of Obligatory Coproducts Supplies.Many fats and oils are generated as obligatory coproducts of other endeavors,with the supply relatively inelastic to price change.Examples include(1)slaughtering and dressing of animals and poul-try,with hand trimming of the fatty tissues at the packing plant or in-store meats department;(2)disposal of spent frying oils from restaurants,skimmings from grease traps,and dead animals from pastures and feedlots—all necessary for sani-tation,public health,and environmental interests;(3)production of high protein content soybean andfish protein meals;(4)growing of cottonfiber for domestic and world markets,with cottonseed as a coproduct;and(5)development of the324FATS AND OILS IN FEEDSTUFFS AND PET FOODSTABLE1.U.S.Sources of Rendered Animal Fats and Oil(1).Fat Produced Source Number Slaughtered(or Kilogram of Product)Percent of Total Metric Tons Steers and heifers28,000,00037.31,527,000 Cull cows and bulls7,000,000 3.9159,000 Market pigs83,000,00021.3874,000 Cull sows and boars5,000,000 2.291,000 Broiler5,200,000,0008.7355,000 Turkey242,000,000 1.457,000 Dead stock(1,636,000,000) 5.2213,000 Restaurant grease(1,023,000,000)16.7682,000 Miscellaneous— 3.3136,000 Total domestic inedible—100.04,125,000 domestic corn starch and sweeteners industry,which has generated enough corn germ to make corn oil the second major oil currently produced in the United States.Because of these situations,the production of the major portion of feed grade fats and some oil-bearing feedstuffs is likely to continue regardless of their market prices.However,future prices will reflect(1)domestic competition between feed, oleochemicals,and detergent industries needs;(2)opportunities to ship into global markets;and(3)abilities to import lower cost fats like palm oil and stearin.Sources of Fats,Oils,and Tallows.The total world production of fats and oils is estimated at76.2million MT.It consists of59.2million MT of edible vegetable fats and oils(soybean oil,16.9million;palm oil11.5million;rapeseed and canola oil,9.1million;sunflower seed oil,7.6million;cottonseed oil,4.2million;peanut oil,3.4million;coconut oil,2.9million;olive oil,2.1million;and palm kernel oil, 1.5million),butter fat,5.3million;total marine oils,1.1million;and total tallows and greases,7.0million(28).Approximately4.1million MT of inedible animal fats are rendered in the United States annually(Table1).The major sources,in order of decreasing tonnage,are beef packing,pork packing,spent restaurant fats,and broiler and turkey processing. Only about5%of the total supply of inedible fat is recovered from dead stock(1).Use of Domestically Produced Tallows.Currently,approximately35%of domestically produced inedible tallow is exported,leaving about2.7million MT available for domestic use(1).Rouse(29)reported that domestic use of inedible tallow increased by63%,from0.81million MT in1950to1.3million MT in 1991.In1950,about72%of the available domestic inedible tallow(0.58million MT)was used in making soap and hardly any in animal feeds.With the develop-ment of synthetic detergents,the use of edible tallows in soap making dropped to 0.15million MT or12%of the total in1991,and animal feeds rose to using about 62%of the domestic supply.The largest use for inedible fats worldwide is in animal feeds.Domestic use in various feeds is shown in Table2.Approximately56.2%is used in broiler and tur-key feeds,and another2.7%in feeding poultry layers(29).It has been estimatedAVAILABILITY,CHARACTERISTICS,AND COMPOSITION325 TABLE2.Estimated Use of Fats and Oils in DomesticAnimal Feeds in1993(29).Fat UsedType of Feed Percent of Total Million Metric TonsBroilers34.8591Turkeys21.4364Pet foods16.0273Swine10.7182Beef cattle 5.491Dairy cattle 4.882Layers 2.745Veal 2.136Fish 2.034Total100.001,698that inclusion of3–4%fat in all feeds,a level favored by some nutritionists and feeders,would use about2.5million MT of fats in domestic animal feeds(1).3.2.Definitions of Fats and Related Products Used in Feeding Industrywide definitions for feed fats products are still being DA and NRA definitions of rendering and tallows and greases were already discussed.NRA Recommended Standards and Definitions.AFOA grading standards for tallows and greases for industrial uses are shown in Table3(1).Typical analyses TABLE3.American Fats and Oils Association Grading Standards for Tallowand Grease(1).Titer FFA FAC Color Specifications MIU a Grades(Min. C)(Max.%)(Max.)(R&B,Max.)(%) Edible tallow41.00.753None b Lard(edible)38.00.50c None b Top white tallow41.0250.51All-beef packer tallow42.02None0.51 Extra fancy tallow41.035None1 Fancy tallow40.547None1 Bleachable fancy tallow40.54None 1.51 Prime tallow40.5613–11B None1 Special tallow40.01021None1 No.2tallow40.035None None2‘‘A’’tallow39.01539None2 Choice white grease36.0413–11B None1 Yellow grease d1539None2a Moisture,insolubles,unspecifiables.b Moisture,maximum0.20%;insoluble impurities,maximum0.05%.c Lovibond color5.25-inch cell,maximum;rd Peroxide Value4.0ME/K maximum.d Titer minimum,when required,to be negotiated between buyer and seller on a contract by contract basis.326FATS AND OILS IN FEEDSTUFFS AND PET FOODSTABLE4.Typical Analyses of Feed Grade Fats(30).Percent Fatty Acids Titer FAC Color MIU a Iodine FFA b Satu-Unsatu-Lino-Fat Source( C)(Maximum)(%)Value(Maximum%)rated rated leic FGF(for all34–383725515445610 feeds)FGF(for milk38–419145550504 replacers)All-beef tallow38–427140556442 All-pork fat32–383725815366412 All-poultry fat28–351926515287220 Butter fat28–35——32—63372 Vegetable fat28–36—253—425810 (palm oil)a Moisture,insolubles,and unsaponifiables.b Free fatty acids.of feed-grade fats of different origins are shown in Table4(30).Quality speci-fications suggested by the NRA for commonly traded feeding fats are shown in Table5(1).The NRA additionally suggests the following.Feeding fats pass a minimum of20-h active oxygen method(AOM)test.Blended feeding fats contain only tallow,grease,poultry fat,and soapstocks;any other products should be included only with the knowledge and approval of the purchaser.All fat products must be below tolerances for toxic chemicals and pesticide residues;certification is available from most renderers;fats used in poultry rations must be free of the chick edema factor;and all fats should be devoid of contaminants such as heavy metals.TABLE5.National Renderer’s Association Suggested FatQuality Standards for Feeds(1).Choice White Yellow HydrolizedStandard Tallow Grease Grease A/V BlendTotal fatty acids(%)90909090Free fatty acids(%)4–641540–50FAC color1911A37–3945Moisture(%)0.50.5 1.0 1.5Impurities(%)0.50.50.50.5Unsaponifiables(%)0.50.5 1.0 2.5Total MIU(%) 1.0 1.0 2.0 4.0Iodine value48–5858–6858–7985AOM(h)20202020Fats for poultry rations should not contain cottonseed soapstock or other coproducts.Changes to new sources of fats,especially in ruminant and swine feeds and pet foods,should be gradual due to potential differences in palatability from previous sources(1).No standards exist for polyethylene in fats;the practical way to remove it is byfiltering tallow at low temperatures using specialfilter aids;most custo-mers can use tallow containing up to30ppm polyethylene,and a few up to 150ppm(31).Maximum pesticide residues tolerances are0.5ppm for DDT,DDD,and DDE;0.3ppm for Dieldrin;and2.0ppm for PCB(31).Some buyers also have a rate offiltration(ROF)specification,which is defined as the milliliters of tallow at110 C(230 F)that will pass through afilter paper in5min under specified test conditions;a commonly sought value is 35–40ROF;the test identifies fats that may give processing difficulties such as slowfiltration,emulsion,and foaming(31).Poultry fat is rendered mainly from poultry offal collected in packing plants but may include renderings from mortalities,hatchery rejects,and condemned or unmarketable parts of birds.Much of the rendered poultry fat and meal is produced and recycled in integrated growing–processing plant operations,and only limited amounts are available in the open market.AAFCO Definitions—Fats and Oils.Many feed ingredients are coproducts of agribusinesses and are of secondary interest.With some exceptions,little is done currently to process them further,and they are sold as made.The AAFCO defines feed fats as follows.Animal fat(AAFCO number33.1)is obtained from the tissues of mammals and/or poultry in the commercial processes of rendering or extracting.It consists predominantly of triacylglyerol esters of fatty acids and contains no additions of free fatty acids or other materials obtained from fats.It must contain,and be guaranteed for,not less than90%total fatty acids,not more than2.5%unsaponifi-able matter,and not more than1%insoluble impurities.Maximum free fatty acids and moisture must also be guaranteed.If the product bears a name descriptive of its kind or origin(e.g.,beef,pork,or poultry),it must correspond thereto.If an anti-oxidant is used,the common name or names must be indicated,followed by the words used as a preservative.Includes IFN4-00-409(animal poultry fat).Vegetable fat,or oil(33.2)is the product of vegetable oil origin obtained by extracting the oil from seeds or fruits that are commonly processed for edible pur-poses.It consists predominantly of glyceride esters of fatty acids and contains no additions of free fatty acids or other materials obtained from fats.It must contain, and be guaranteed for,not less than90%total fatty acids,not more than2%unsa-ponifiable matter,and not more than1%insoluble impurities.Maximum free fatty acids and moisture must also be guaranteed.If the product bears a name descriptive of its kind or origin(e.g.,soybean oil or cottonseed oil)it must correspond。

COCONUT OIL: HEALTH EFFECTSHeli J. Roy, PhD, MBA, RDLSU AgCenterPennington Biomedical Research CenterIntroduction•Coconut oil comes from themeat of matured coconutsharvested from the coconutpalm. It is used in food,medicine and in the industry.Coconut oil is high insaturated fat content, andbecause of it, it has a longself-life.Fat and fatty acids in human healthFat is an important component of the diet:•It is used for making many hormones•It protects our nerves and internal organs as a thermal covering•It is essential for growth•Some fatty acids are essential, we must get them from the diet, and they are used to make important compounds for growth and inmetabolism•It is used for energyFatty Acids•Not all fats are created equal.•There are three types of fatty acids:•Short-chain fatty acids•Medium-chain fatty acids•Long-chain fatty acids•Because of the various lengths of the fatty acids, they are digested and metabolized differently.What’s the difference?Fatty acid type Coconut oil Corn oilMedium chain63%None Long chain saturated30%20% Long chain unsaturated7%80%The major difference between these oilsand how they behave in the body is dueto the different fatty acid compositions.Difference in absorption and use •Short-chain fatty acids are formed in the intestines by friendly bacteria and are rapidly metabolized by the intestinal cells.•Medium-chain fatty acids are absorbed and transported directly to the liver where they are burned for energy. •Long-chain fatty acids are turned into triglycerides and then are taken up by cells and used for energy or are stored.•Bile from the gallbladder is needed to digest long chain fatty acids.Long chain saturated fatty acids•Mainly from animal sources, also from some plants •Makes blood vessels less pliable•Increases heart disease risk•Increases diabetes risk•Increases blood pressure•Increases LDL•Increases triglycerides•Increases inflammation•Reduces HDLLong chain unsaturated omega-6 fatty acids •From vegetable oils (corn, soybean, safflower)•Tend to promote inflammation•Tend to promote chronic diseases (cancer, high blood pressure, diabetes, cardiovascular disease)•Lowers LDL•Essential fatty acids for humansLong chain unsaturated omega-3 fatty acids•From plants and seafood•Most heart healthy•Reduces platelet stickiness•Dilates blood vessels•Reduces blood pressure•Reduces LDL cholesterol•Increases HDL•Reduces triglycerides•Has essential fatty acids for humansMedium chain triglycerides•Are used for source of fat in malabsorption conditions such as IBS,and ulcerative colitis, and in infant formulas. It is also used to increase the energy intake in cystic fibrosis patients. •Affects hormone release from intestines differently than LCFA’s •Inhibits bacterial and virus growth•Reduces LDL and increases HDL•Reduces abdominal fat•Increases fat burning•Not stored in adipose tissue•Reduces cholesterol synthesis by the liver•Does not provide essential fatty acidsBenefits of Coconut oil•Coconut oil contains antioxidants such as vitamin E, provitamin A, polyphenols and phytosterols.•Because coconut oil has a lot of medium-chain fatty acids it can be useful for malabsorption conditions.•May have some antibacterial, antiviral and antifungal properties.•May help support the immune system.•Maintains coagulation factors and therefore does not increase heart disease risk.•Reduces cholesterol and triglyceride levels.•Best result (i.e. reducing heart disease risk) is obtained when combined with safflower, corn, or olive oil.What happens if…•You replace vegetable oils (soy, corn, canola, olive) with coconut oil?•Vegetables oils contain more of the healthful fats (polyunsaturated and monounsaturated) that prevent heart disease and they have essential fatty acids.•Replacing all healthful fats with coconut oil is not prudent sincecoconut oil does not provide any essential fatty acids.•Will receive benefits from the other healthful components incoconut oil (phytosterols etc).•American Heart Association recommends that only 7% of total daily calories come from saturated fat.Coconut Oil in Cooking•Coconut oil is used in cookingbecause it:•Has a higher burning point.•Doesn’t go bad as quickly as someother fats.•Adds a nutty, vanilla-like flavor tofoods.•Is solid at room temperature and canbe used in cooking and baking.•Is used by certain cultures as themain cooking oil.Photo by Amy Selleck, FlickrConclusions •Can use virgin coconut oil prudently.•Does not seem to increase heart disease risk.•Is safe to use in small amounts.•Can add flavor to cultural foods.References•Monica L. Assuncao, Haroldo S. Ferreira, Aldenir F. dos Santos, Cyro R. Cabral Jr., Telma M. M. T. Florencio. Effects of Dietary Coconut Oil on the Biochemical and Anthropometric Profiles of Women Presenting Abdominal Obesity. Lipids (2009)44:593–601.•Andre C Bach and Vigen K Babayan. Medium-chain triglycerides: an update. Am. J. clin. Nutr. 36: 950-962, 1982.•Preeti Chandrashekar, B.R. Lokesh, A.G. Gopala Krishna. Hypolipidemic effect of blends of coconut oil with soybean oil or sunflower oil in experimental rats. Food Chemistry 123 (2010) 728–733.•William E Connor. Importance of n23 fatty acids in health and disease. Am J Clin Nutr 2000;71(suppl):171S–5S.•Eqbal M. A. Dauqan, Halimah Abdullah Sani, Aminah Abdullah and Zalifah Mohd Kasim. Fatty Acids Composition of Four Different Vegetable Oils (Red Palm Olein, Palm Olein, Corn Oil and Coconut Oil) by Gas Chromatography. IPCBEE vol.14 (2011). •Conrado S. Dayrit. Coconut oil in health and disease: Its and monolaurin’s potential as a cure for HIV/AIDS. Cocotech Conference. Chennai, India. July 25, 2000.•Nicole M. de Roos, Evert G. Schouten and Martijn B. Kata. Consumption of a Solid Fat Rich in Lauric Acid Results in a More Favorable Serum Lipid Profile in Healthy Men and Women than Consumption of a Solid Fat Rich in trans-Fatty Acids. J. Nutr. 131: 242–245, 2001References•Alan B. Feranil, Paulita L. Duazo, Christopher W. Kuzawa, and Linda S. Adair. Coconut oil predicts a beneficial lipid profile in pre-menopausal women in the Philippines. Asia Pac J Clin Nutr. 2011 ; 20(2):190–195.•William S. Harris, Dariush Mozaffarian, Eric Rimm, Penny Kris-Etherton, Lawrence L. Rudel, Lawrence J. Appel, Marguerite M. Engler, Mary B. Engler and Frank Sacks. Omega-6 Fatty Acids and Risk for Cardiovascular Disease : A Science Advisory From the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. Circulation. 2009;119:902-907.•Edward D. Korn. Clearing factor, a Heparin activated lipoprotein lipase: II. Substrate specificity and activation of coconut oil. J. Biol. Chem. 1955, 215:15-26.•Charles S. Lieber, Andre LeFevre, Norton Spritz, Lawrence Feinman, and Leonore M. DeCarli. Difference in Hepatic Metabolism of Long-and Medium-Chain Fatty Acids: the Role of Fatty Acid Chain Length in the Production of the Alcoholic Fatty Liver. The Journal of Clinical Investigation Vol. 46, No. 9, 1967.• D Mozaffarian and R Clarke. Quantitative effects on cardiovascular risk factors and coronary heart disease risk of replacing partially hydrogenated vegetable oils with other fats and oils. European Journal of Clinical Nutrition (2009) 63, S22–S33.References•K.G. Nevin, T. Rajamohan. Virgin coconut oil supplemented diet increases theantioxidant status in rats. Food Chemistry 99 (2006) 260–266.•K.G. Nevin, T. Rajamohan. Influence of virgin coconut oil on blood coagulation factors, lipid levels and LDL oxidation in cholesterol fed Sprague Dawley rats. European e-Journal of Clinical Nutrition and Metabolism (2008) 3, e1ee8.•John B. Ohlrogge. Regulation of fatty acid synthesis. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1997. 48:109–136.• A.R. Oyi, J.A. Onaolapo and R.C. Obi. Formulation and Antimicrobial Studies ofCoconut (Cocos nucifera Linne) Oil. Research Journal of Applied Sciences,Engineering and Technology 2(2): 133-137, 2010.•Andrea A. Papamandjaris, Diane E. MacDougall, and Peter J.H. Jones. Minireview.Medium chain fatty acid metabolism and energy expenditure: Obesity treatmentimplications. Life Sciences 62:14, 203-1215,1998.•Haji Ibrahim Haji Abr. Rahman. The chemistry of coconut oil. 2000.•Malongil B. Reena and Belur R. Lokesh. Hypolipidemic Effect of Oils with Balanced Amounts of Fatty Acids Obtained by Blending and Interesterification of Coconut Oil with Rice Bran Oil or Sesame Oil. J. Agric. Food Chem. 2007, 55, 10461–10469.References•M.B. Reena, T.P.Krishnakantha, B.R.Lokesh. Lowering of platelet aggregation and serum eicosanoid levels in rats fed with a diet containing coconut oil blends with rice bran oil or sesame oil. Prostaglandins, Leukotrienes and Essential Fatty Acids 83 (2010) 151-160.•Patty W Siri-Tarino, Qi Sun, Frank B Hu, and Ronald M Krauss. Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr2010;91:502–9.•Kapila N. Seneviratne, Chamil D. HapuarachchI, Sagarika Eka. Comparison of the phenolic-dependent antioxidant properties of coconut oil extracted under cold and hot conditions. Food Chemistry 114 (2009) 1444–1449.•Marie-Pierre St-Onge and Peter J. H. Jones. Physiological Effects of Medium-Chain Triglycerides: Potential Agents in the Prevention of Obesity. J. Nutr. 132: 329–332, 2002.•M. K. Vu, M. Verkijk, E. S. M. Muller, I. Biemond, C. B. H. W. Lamers, A. A. M. Masclee. Medium chain triglycerides activate distal but not proximal gut hormones. Clinical Nutrition (1999) 18(6): 359-363.•Lih-ling Wang, Bao-kang Yang, Kirk L. Parkin and Eric A. Johnson. Inhibition of Listeria monocytogenes by Monoacylglycerols Synthesized from Coconut Oil and Milkfat by Lipase-Catalyzed Glycerolysis. J. Agrlc. Food Chem. 1993, 41, 1000-1005.。

梁燕群，李玲. 红心火龙果替代部分脂肪对香肠蛋白质理化特性和脂质氧化的影响[J]. 食品工业科技，2023，44（8）：71−77. doi:10.13386/j.issn1002-0306.2022060308LIANG Yanqun, LI Ling. Effects of Red Pitaya Replacing Part of Fat on Physicochemical Properties of Protein and Lipid Oxidation of Sausage[J]. Science and Technology of Food Industry, 2023, 44(8): 71−77. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2022060308· 研究与探讨 ·红心火龙果替代部分脂肪对香肠蛋白质理化特性和脂质氧化的影响梁燕群，李　玲*（临沂大学生命科学学院，山东临沂 276000）摘　要：传统香肠的脂肪含量通常较高，不符合低脂健康的消费发展需求，研究脂肪替代物，创制新型低脂香肠制品具有重要意义。

本研究以猪后腿肉为原料，并以火龙果果肉替代香肠原始配比中10%、30%、50%的脂肪，分析其对香肠蛋白质溶解度、色差、感官品质、巯基含量、表面疏水性、荧光强度、酸价及硫代巴比妥酸反应物值（TBARs ）等的影响。

结果表明，随火龙果比例的增加，总蛋白、肌浆蛋白和肌原纤维蛋白溶解度均显著增加（P <0.05），与对照组相比，30%组分别增加12.1%、8.4%和18.6%。

感官评价结果表明，30%组各方面都高于其他组。

与对照组相比，10%组巯基含量显著增加，表面疏水性显著减少（P <0.05）。

综上，红心火龙果替代部分脂肪加入至香肠中能够增加蛋白质溶解度、提升感官品质、抑制脂质氧化，且当添加量为30%时，香肠品质最佳。

肥胖的原因英语作文Title: The Causes of Obesity。

Obesity has become a prevalent health issue worldwide, affecting millions of individuals across all age groups. This condition not only poses significant health risks but also imposes a substantial economic burden on society. Understanding the underlying causes of obesity is crucial in developing effective prevention and intervention strategies. In this essay, we will explore the primary factors contributing to obesity.First and foremost, dietary habits play a central role in the development of obesity. The consumption of high-calorie, processed foods that are rich in fats, sugars, and refined carbohydrates has become increasingly common in modern society. These foods are often convenient and affordable but lack essential nutrients. Excessive intake of such foods leads to an imbalance between energy intake and expenditure, resulting in weight gain over time.Moreover, sedentary lifestyles have become the norm for many individuals, contributing significantly to the obesity epidemic. With the advent of technology and theproliferation of desk jobs, physical activity levels have declined sharply. Instead of engaging in regular exercise or outdoor activities, people spend long hours sitting in front of screens, whether it be computers, televisions, or smartphones. This lack of physical activity not only reduces calorie expenditure but also negatively impacts metabolic health.Furthermore, environmental factors also play a role in the development of obesity. Socioeconomic status, access to healthy foods, and neighborhood characteristics can all influence dietary choices and activity levels. Individuals from low-income communities may have limited access to fresh produce and affordable recreational facilities, making it challenging to maintain a healthy lifestyle. Additionally, obesogenic environments, characterized by the abundance of fast food outlets and the scarcity of safe outdoor spaces, promote unhealthy behaviors and contributeto weight gain.Genetic predisposition is another important factor that cannot be overlooked in the discussion of obesity. While lifestyle choices ultimately determine weight status, genetic factors can influence an individual'ssusceptibility to obesity. Certain gene variants may affect metabolism, appetite regulation, and fat storage, making some individuals more prone to gaining weight than others. However, it's essential to recognize that genetics alone do not determine destiny, and lifestyle modifications can mitigate genetic predispositions to obesity.Moreover, psychological and emotional factors can also contribute to obesity. Stress, depression, anxiety, and trauma can lead to emotional eating as a coping mechanism. Food may serve as a source of comfort or distraction from negative emotions, leading to overeating and weight gain. Additionally, cultural norms and societal pressures regarding body image can influence attitudes towards food and exercise, potentially exacerbating disordered eating behaviors.In conclusion, obesity is a complex and multifaceted health issue influenced by various factors. Dietary habits, sedentary lifestyles, environmental influences, genetic predisposition, and psychological factors all contribute to the development of obesity. Addressing this epidemic requires a comprehensive approach that encompasses education, policy changes, community interventions, and individual behavior modifications. By understanding the root causes of obesity, we can work towards creating healthier environments and promoting better health outcomes for all.。

The Effects of Fast FoodFast food has become an integral part of our modern lifestyle, but it comes with a range of significant effects on our health and society.One of the most obvious negative impacts is on our physical health. Fast food is often high in calories, unhealthy fats, sugar, and salt. Consuming it regularly can lead to weight gain and obesity. The excessive intake of these ingredients can increase the risk of various chronic diseases such as heart disease, diabetes, and high blood pressure. For example, a person who frequently indulges in burgers, fries, and sugary sodas is more likely to have elevated cholesterol levels and insulin resistance.It also lacks essential nutrients like vitamins, minerals, and fiber that our bodies need for proper functioning. This can result in nutritional deficiencies and weakened immune systems. Long-term reliance on fast food can make us prone to frequent illnesses and fatigue.The mental health aspect should not be overlooked. The guilt and dissatisfaction that often follow overeating fast food can contribute to feelings of low self-esteem and body image issues. Stress eating of fast food as a coping mechanism can create a vicious cycle.Fast food consumption has cultural and environmental implications as well. The dominance of fast food chains has led to a decline in traditional, home-cooked meals, eroding cultural food traditions. From an environmental perspective, the production and packaging of fast food generate a large amount of waste and contribute to pollution.It also has an influence on children's eating habits. Kids who are exposed to fast food advertising and frequent visits to these restaurants are more likely to develop a preference for unhealthy options at an early age, setting the stage for potential health problems later in life.In conclusion, while fast food offers convenience and immediate gratification, its effects on our health, culture, and environment are far-reaching. Making more informed and balanced food choices is crucial for our well-being and the sustainability of our society.。

雅思作文儿童肥胖率上升的原因英文回答：Childhood obesity is a complex issue with a multitude of contributing factors. The rise in childhood obesity rates can be attributed to a combination of biological, environmental, and societal changes.From a biological perspective, genetics play a role in determining an individual's susceptibility to obesity. However, environmental factors are equally, if not more, influential. The increased availability of processed foods, sugary drinks, and fast-food restaurants has made it easier for children to consume excessive calories. Additionally, sedentary lifestyles and decreased physical activity have contributed to the accumulation of excess weight.Socioeconomic status also plays a role in childhood obesity. Poverty often limits access to healthy food options, making it more difficult for children from low-income families to maintain a balanced diet. Moreover, children living in disadvantaged neighborhoods may haveless access to safe and accessible places for exercise.Another significant factor is the role of advertising. The relentless bombardment of children with advertisements for unhealthy foods contributes to their desire for these products. Furthermore, the marketing of toys and other products that promote sedentary behavior encourageschildren to spend less time engaging in physical activity.Cultural factors also influence childhood obesity rates. In some cultures, larger body sizes are viewed positively, which can lead to less emphasis on maintaining a healthy weight. Additionally, certain cultural traditions mayinvolve foods that are high in calories and fat,contributing to weight gain.中文回答：儿童肥胖率上升的原因。

如何提高猪肉价值英语作文Title: Strategies to Enhance the Value of Pork。

In recent years, the pork industry has faced numerous challenges, including fluctuating prices and changing consumer preferences. To address these challenges and enhance the value of pork, various strategies can be implemented. In this essay, we will explore some effective approaches to elevate the value of pork products.Firstly, enhancing the quality of pork through improved breeding and farming practices is crucial. Breed selection plays a vital role in determining the quality of pork, including its taste, texture, and nutritional content. By focusing on breeding programs that prioritize desirable traits such as marbling, tenderness, and flavor, farmers can produce pork of superior quality. Additionally, implementing modern farming techniques, such as controlled feeding and housing systems, can further improve theoverall quality of pork while ensuring animal welfare.Furthermore, promoting the sustainability and environmental friendliness of pork production can increase its value in the eyes of consumers. Sustainable practices, such as reducing water and feed waste, minimizing greenhouse gas emissions, and protecting natural habitats, demonstrate a commitment to environmental responsibility. Consumers are increasingly concerned about the environmental impact of their food choices, and by highlighting the sustainability of pork production, farmers can attract environmentally conscious consumers and command a premium price for their products.In addition to quality and sustainability, branding and marketing play a crucial role in enhancing the value of pork. Establishing a strong brand identity that emphasizes the unique qualities of the product, such as its heritage breed, organic certification, or specialty feeding regimen, can differentiate it from competitors and create a sense of value and exclusivity. Effective marketing campaigns that highlight the provenance, quality, and culinary versatility of pork can also attract new customers and encourageexisting ones to trade up to higher-value cuts.Moreover, diversifying pork products and exploring new markets can expand the reach and appeal of pork to a wider audience. Developing innovative pork-based products, such as ready-to-cook meal kits, value-added snacks, or gourmet charcuterie, can cater to evolving consumer preferences for convenience, health, and novelty. Additionally, targeting new markets, both domestically and internationally, can open up opportunities for increased sales and revenue growth. By tapping into emerging markets or niche segments, such as premium restaurants, health-conscious consumers, or international export markets, farmers can leverage the value of pork and maximize profitability.In conclusion, enhancing the value of pork requires a multifaceted approach that encompasses quality improvement, sustainability initiatives, branding and marketing efforts, and product diversification. By focusing on these strategies, farmers can position pork as a premium product that commands higher prices and greater consumer demand. Ultimately, by continuously innovating and adapting tochanging market dynamics, the pork industry can thrive and prosper in the years to come.。

IntroductionResearch for new bio-efficient antioxidants has particularly focused on natural antioxidants to respect the consumer concerns over safety and toxicity. Grape seeds and by-products of wine/grape juice processing provide an abundant source of flavonoids, in which the most abundant classes include the flavan-3-ols. Grape seeds from grape juice and wine processing can be se-parated, extracted, dried and purified into grape seed extract (GSE) which contain polyphenolic compounds. Nutritional interest in polyphenolic compounds has increased greatly in light of their antioxidant activity (Scalbert and Williamson, 2000), but there have been very few studies on the digestibility and intestinal degradation of polyphenols and other major constituents. It is noteworthy that most reports on the beneficial effects of polyphenols have been obtained from in vitro studies, and more detailed investigations are required to extra-polate these results to in vivo situations. In this sense, clinical data has shown the antioxidant potential of grape seed (Shi et al., 2003).The antioxidant compounds present in grape have been identified as phenolic acids (benzoic and hydro-xycinnamic acids), stilbene derivatives, flavan-3-ols (catechin and epicatechin), flavonols (quercetin and myricetin), and anthocyanidins (Caillet et al., 2006). Shi et al. (2003) reported that the antioxidant potential of grape seed is twenty and fifty fold greater than vita-mins E and C, respectively arising from increased levels of polyphenols proanthocyanidins and oligomers of flavan-3-ol units, especially catechin and epicate-chin present in GSE (Yilmaz and Toledo, 2004). The antioxidant activity of GSE has been reported to improve the oxidative stability in a variety of food systems in-cluding cooked beef (Ahn et al., 2002), turkey and pork patties, and cold stored turkey meat (Lau and King, 2003; Mielnik et al., 2006; Carpenter et al., 2007). However, the use of such natural antioxidants in animal nutrition could be limited to the low bioavailability of polyphenols.Previous experiments in our laboratory (Goñi et al., 2007; Brenes et al., 2008) have shown an increase in the antioxidant activity of broiler diet, excreta, and meat as a result of the dietary administration of grape pomace concentrate. The objective of the present study was to assess the effect of increasing dietary concentra-tions of a commercial grape seed extract on the perfor-mance parameters, protein, and extractable polyphenols digestibilities, and the antioxidant activity in diet and excreta of chickens.Materials and methodsA total of 240, 1-day-old male broiler Cobb chicks, were housed in electrically heated starter batteries in an environmentally controlled room. The chicks were allocated to 40 pens, each pen containing six chicks, to receive four dietary treatments with ten replicates of each treatment during 21 d. Diets in mash form and water were provided ad libitum. At 3 weeks of age, 20pens were randomly selected with six birds per pen and five pens per treatment, and moved to grower-finisher batteries during the rest of 21 d of experimen-tal period (21-42 d). Celite(Celite Corp., Lompoc, CA 93436) a source of acid insoluble ash (AIA) was added at 10 g kg–1to all diets as an indigestible marker. Expe-rimental procedures were approved by the Universi-ty Complutense of Madrid Animal Care and Ethics Committee in compliance with the Ministry of Agricul-ture, Fishery and Food for the Care and Use of Animals for Scientific Purposes. Ingredients and nutrient com-position of diets are shown in Table 1. Experimental diets were as follows: (1) control corn-soybean diet (CS); (2) CS+0.6 g kg–1grape seed extract (GSE); (3) CS+1.8 g kg–1GSE; (4) CS+3.6 g kg–1GSE. The GSE contained 95% of total polyphenols of which 38-42% was catechin and total proanthocianidins (composition as stated by the manufacturer- Naturex, Avignon, France).Collection of samples and measurements At 21 and 42 d of age the chicks (20 and 10 ran-domly selected chicks respectively per treatment, 2 per replicate) were sacrificed by cervical dislocation and liver, pancreas, spleen and abdominal fat were weighed and the length of duodenum, jejunum, ileum and ceca were measured. The ileum was quickly dissected out and the content expressed by gentle manipulation into a plastic container and stored at –20°C. Digesta were pooled from two birds of each replicate within the same treatment. Diet and ileal contents were freeze-dried and ground (1 mm screen) and subsequently analy-sed for N-Kjeldahl and celite. Clean stainless steel collection trays were also placed under each cage and excreta from the birds were collected for 48 h. A sub-sample of excreta was collected in polyethylene bags and freeze-dried for subsequent determination of extractable polyphenols (EP), and antioxidant acti-vity.Grape seed extract in chicken diets327328 A. Brenes et al. / Span J Agric Res (2010) 8(2), 326-333Grape seed extract in chicken diets329330 A. Brenes et al. / Span J Agric Res (2010) 8(2), 326-333Grape seed extract in chicken diets331bolism of polyphenols is necessary to evaluate their biological activity. In the literature reviewed we have not found information relative to polyphenols digesti-bility in chickens and scarce data are available on polyphenol absorption when these compounds are present in the intestine, together with other dietary constituents. Therefore, in a complex diet, polyphenols are most of the time associated with many constituents that could influence their absorption. In the current experiment, the fecal digestibility of the extractable polyphenols reached values in a range of 57 to 69%. Similar results have been obtained in our lab using dietary grape pomace concentrate in chicken diets (Brenes et al., 2008), and in rats by Goñi and Serrano (2005). Wren et al. (2002) showed that flavonoid and flavan-3ols metabolites are absorbed in rats through the intestinal lumen and are further metabolised by methylation, oxidation or glucuronic conjugation. There is also evidence in support of absorption of monomeric catechins and proanthocyanidins through the human intestinal caco-2 epithelial cells (Deprez et al., 2000; Faria et al., 2006). Another study by Tsang et al. (2005) reported the absorption and metabolism of catechin and proanthocyanidins up to trimers in urine following the oral intake of GSE.In the current experiment an increase in antioxidant activity in diet and excreta was observed by the inclu-sion of GSE at 21 and 42 days of age. This result is similar to those reported in chickens (Goñi et al., 2007; Brenes et al., 2008) and rats (Goñi and Serrano, 2005). The nutritional effects of polyphenols would be a con-sequence of the absorbed monomers and aromatic acid, the interaction of unabsorbed polyphenols with compo-nents of the intestinal tract, or both. The increase in the antioxidant activity of grape polyphenols in the excreta suggests that part of extractable polyphenols are degraded by intestinal microflora. Goñi et al. (2005) reported that intestinal bacteria showed a high capacity to degrade extractable polyphenols in rats. Deprez et al.(2000) and Ward et al.(2004) also reported that major polyphenolic constituents of grape polyphe-nols (polymeric proanthocyanidins) were degraded by human colonic microflora into smaller compounds including phenolic acids that could be absorbed and metabolized.The present study aimed to support the previous results obtained in chicken using grape pomace con-centrate and provides evidence that GSE can be incor-porated up to 3.6 g kg–1without impair performance, digestive organ size, and protein digestibility. Our results also confirm that polyphenols present in GSE were absorbed at sufficient levels to contribute and modulate the antioxidant activity in diet and excreta. This work has also shown that the phytochemicals present in grapes have antioxidant activity and that this activity in the grape seed extract is related with total phenolic content. 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