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酵母培养物对育肥羊生长性能和免疫指标的影响毛正梁，郭娟江苏省海安高新区畜牧兽医站，江苏海安 226600摘要［目的］研究基础日粮中添加不同水平酵母培养物对育肥羊生长性能和免疫指标的影响，寻求具有促生长作用的替抗产品。
［方法］选用160只体格健壮、体质量（40±2） kg的3~4月龄的育肥公羊作为研究对象，采用随机数字表法分为4组，分别饲喂在基础日粮中添加0%（对照组）、0.3%（低剂量组）、0.6%（中剂量组）和0.9%（高剂量组）酵母培养物的试验饲粮，试验期90 d。
分别测定育肥羊的平均日采食量、平均日增质量和料重比，并对育肥羊静脉血清中的IgG、IgA和IgM含量进行测定。
［结果］与对照组相比，3个试验组育肥羊平均日增质量和平均日采食量显著升高，料重比显著降低，静脉血清中IgG、IgA和IgM含量显著提高，其中，添加0.6%酵母培养物的试验组育肥羊平均日增质量为176.56 g，血清中IgG、IgA和IgM含量分别为29.25、191.25、2 165.49 μg/mL。
［结论］饲粮中添加酵母培养物在一定程度上改善育肥羊的生长性能，提高育肥羊的免疫能力，添加0.6%酵母培养物的效果为佳。
关键词酵母培养物；高精料饲粮；育肥羊；生长性能；免疫指标Effects of adding yeast culture on the growth performance and im‐mune indexes of fattening sheepMAO Zhengliang, GUO JuanHaian High-tech Zone Animal Husbandry and Veterinary Station, Haian 226600, ChinaAbstract[Objectives] The effects of adding different levels of yeast culture to the basic diet on the growth performance and immune indexes of fattening sheep were studied to provide reference for seeking products instead of antibodies with effects of promoting growth.[Methods] 160 healthy fatten‐ing rams aged 3-4 months with a body weight of (40±2) kg were selected and randomly divided into 4 groups using a random number table method. They were fed with experimental diets supplemented with 0(control group), 0.3%(low dose group), 0.6%(medium dose group), and 0.9%(high dose group) yeast culture in the basic diet for 90 days. The average daily intake of feed, average daily gain of weight, and the ratio of feed to weight in fattening sheep were determined. The content of IgG, IgA, and IgM in the venous serum of fattening sheep were measured as well.[Results] Compared with the control group, the average daily intake of feed, average daily gain of weight of fattening sheep in the收稿日期：2023-09-11作者简介：毛正梁,男，1983年生，兽医师。
酵母培养物在反刍动物饲料中的应用酵母培养物（Yeast Culture，YC）是一种在特定工艺条件控制下由酵母菌在特定的培养基上经过充分的厌氧发酵后形成的微生态制品，它主要由酵母菌及其代谢产物以及经过发酵后变异的培养基和少量已无活性的酵母细胞所构成。
YC在通过对瘤胃微生物调控提高反刍动物生产性能等方面具有重要作用。
1 酵母培养物作用机理YC的作用机制目前尚不确定, 主要有控氧理论、小肽营养代谢扳机理论、营养理论。
控氧理论认为酵母菌是耗氧菌，其在瘤胃中消耗氧气, 从而造成瘤胃的厌氧环境有利于瘤胃的发酵；营养理论认为YC中含有有机酸、维生素、钙、磷等营养成分，在瘤胃中可以对微生物起到营养作用，从而加大了发酵的力度；小肽营养代谢扳机理论认为，YC中可能含有一种结构类似于小肽的物质，对瘤胃内的微生物具有很大的刺激作用。
2 酵母培养物对反刍动物的作用2.1 YC在反刍动物不同发育阶段的作用效果YC在奶牛不同发育阶段所起的作用不同。
在幼犊瘤胃发育过程中，细菌和底物间存在相互作用，YC对提高及稳定犊牛瘤胃与肠道pH值有重要作用。
有报道认为,在犊牛开食料中添加啤酒酵母等可减轻反刍动物对日粮的应激，维持旺盛的消化代谢能力。
这可能是由于YC组分中含有催化物质并能产生多种次生性代谢产物及其具有的酶的性质。
成年反刍动物饲料中添加YC主要是稳定瘤胃内环境，提高瘤胃中纤维分解菌群和厌氧菌的浓度，提高VFA的产量和改变VFA比例，而起到营养与保健作用。
在育成牛日粮中添加0.6%的YC可提高日增重13.6%, 料重比下降14.9%（金加明，2004）。
在泌乳早期添加YC可使日平均产奶量增加0.48～1.74 kg(魏时来, 2000)。
Kim等(2006)研究证实，YC对奶牛过渡期食欲减退有缓解作用，同时，也可降低由于干物质采食量下降对奶牛体况的影响（Erasmus等，2005）。
YC在从干奶日粮到高能日粮的过渡阶段能发挥有效稳定瘤胃环境的作用，因此可以推测在泌乳早期(包括产前2周左右到产后4周)这段时间是饲喂的最佳时机。
酵母培养物及其在养殖业中的应用美国达农威公司彭一凡甄玉国真正的酵母培养物是一种复杂的发酵产品。
随着畜牧业生产发展对改善动物健康、提高产品质量和控制生产成本以及追求养殖效益最大化等目标需求的日益凸显，酵母培养物及其在改善动物健康和促进生产性能发挥方面的自然作用正在引起人们越来越多的关注和探索。
酵母培养物是根据微生物代谢理论及应用生物发酵工程技术制造而成的含有多种代谢产物成分的纯天然产品。
它的生产制作以获取更多的酵母细胞外代谢产物为目的。
与人类利用微生物的代谢产物作为食品和医药有所不同，酵母培养物里的代谢产物被用来作为动物胃肠道内微生物的营养底物。
酵母培养物这个名称很容易让人与酵母本身联系在一起。
实际上，已经制成的酵母培养物无论是功能作用还是实际用途都跟酵母没有必然或直接的关联。
从这个意义上讲，与其说酵母培养物是这类产品的名称倒不如说是该类产品由来的一种表述更为贴切一些。
酵母培养物的生产过程是一个使得所选用的酵母菌种在精心设置的生产工艺环境下利用特制的培养基进行深度发酵并产生细胞外代谢产物的生物反应过程。
酵母菌种、培养基和发酵生产工艺是构成酵母培养物生产的三大要素。
经过发酵生产后，酵母培养物所形成的终端产品是一个包含了少量酵母细胞、变异培养基和细胞外代谢产物的混合物。
与其它酵母类产品所不同的是，酵母培养物的主要作用成分是在该产品的生产过程中酵母细胞对培养基发酵产生的细胞外代谢产物，而并非酵母细胞本身。
尽管酵母菌在酵母培养物的生产过程中是不可或缺的要素之一，但它们也只不过是被用来在该产品制作过程中进行发酵和生产代谢产物的一种工具而已。
一旦终端产品被形成，酵母菌的使命就已经完成。
此后，酵母细胞在该产品中的存活与否及其数量多寡已对酵母培养物本身没有任何实际的意义可言，也不会对它的使用效果产生任何的影响。
那些将酵母培养物描述成“活酵母”或“死酵母”产品的说法显然是对它的一种误解。
生产酵母培养物时所使用的培养基和发酵工艺控制参数对其终端产品中代谢产物的组成、浓度及其生物利用度的稳定性有着至关重要的影响。
174 ·2018.2前言酵母菌指的是在生产厌氧条件下，能够通过发酵糖类，不同化乳糖，高级烃类以及不同化硝酸盐的真菌类别。
其分泌产物富含动物机体所需的矿物质，ＶＢ，ＶＥ等动物机体所必须的维生素。
此外，该菌类胞壁中含有的葡聚糖、甘露糖等成分，被广泛的应用于家禽家畜的日粮搭配中。
在传统家禽、家畜养殖业，水产养殖业乃至以貂，狐等毛皮动物的特种养殖上，都陆续被证实其具有提高生产性能，机体免疫力的功效。
１在家禽养殖中的应用目前国内在家禽养殖中对于益生菌的添加应用较为纯熟，添加形式包括原菌，提取液，多糖制剂等。
在肉禽饲养实验中，酵母菌能够提升糖酶活性，在肉鸭的生产性能使用中，使用布拉迪酵母菌能够在不损害肉鸭黏膜蛋白质含量的前提下，进一步提升肉鸭消化道对营养物质的吸收利用效率，在十二指肠、回肠肠道绒毛等肠道吸收组织的生长有较好的促生长效果［１］。
在肉鸡的饲养中，酵母在食物中添加比例，选用不同类别的酵母会起到不同程度的促生长作用，多糖制剂灌服幼禽发育能够起到促日增重的作用［２］。
国内在对肉鸡饲料添加微囊化酵母［３］实验中，发现酵母添加组实验组可显著提高血清中的Ｉｇ Ｍ含量。
在提升血清中免疫因子的探究上，国内研究陆续证明在日粮中添加酵母，与基础日粮相比，能够显著提高血清中免疫因子水平。
２在家畜养殖中的应用对于酵母菌所起的功能，目前有观点认为与酵母本身的代谢活动有关。
在猪、牛、羊等常见家畜的相关实验中发现，有益生酵母的使用能够帮助调理胃肠道菌群，在不被抗生素降解的情况下起到协同作用，帮助促进家畜机体的消化功能。
在母猪生产中按照适量比例添加，能够起到降低热应激导致的采食量下降的问题［４］。
添加酵母抽提物，对生猪养殖业中猪的生长性能和免疫状态具有可观的短期影响，肖旭等研究指出饲喂干酵母能够提升哺乳仔猪的Ｔ淋巴细胞转化率［５］。
酵母菌制剂目前被广泛应用于草食反刍动物的饲养中，在牛饲养［６］中添加酵母制剂，能够缩短其采食间隔时间，能够有效提高乳脂率。
仔猪断奶是生猪养殖的关键时期。
在断奶过程中，仔猪由于受到一系列环境因素的刺激，会产生各种应激症状，从而影响仔猪的健康生长（葛雨竹等，2019；袁丽，2018）。
在防治仔猪断奶应激综合症上，抗生素是目前最有效的方案，可以有效缓解仔猪腹泻并促进其生长，但畜牧生产中抗生素滥用情况十分严峻，寻找安全、有效的替抗产品是目前畜牧行业的大趋势。
酵母培养物属于微生态制剂，其成分比较复杂，既包括酵母细胞本身的营养，也含有发酵后形成的代谢产物，在饲料生产中通常用作添加剂使用（孙展英等，2013）。
关于其作用机制也有诸多争议，有人认为是酵母细胞的营养起作用，有的则认为是发酵形成的代谢产物对动物起到促生长作用。
王玲等（2015）研究表明，将1%复合酵母培养物添加到奶牛精料中，奶牛的产奶量、乳成分等生产性能相关的指标得到明显改善；而将0.8%的酵母培养物添加到大麦-高粱型猪饲料中也发现育肥猪生产性能提高，且肉品质得到一定改善（路则庆等，2016）；肉鸡上的研究也有类似结果，将0.1%的白酒糟酵母添加到饲料中，肉鸡日增重提高、料重比降低，同时还可以使肉鸡机体抗氧化能力等到改善（马友彪等，2018）。
据此，本试验选取21日龄断奶仔猪，在对照组饲喂基础日粮的条件下，试验组分别添加酵母培养物和金霉素，研究仔猪生长性能、免疫功能、抗氧化指标的变化，探讨饲料中添加酵母培养物和金霉素的使用效果，比较酵母培养物和金霉素各自的特点，为其在饲料生产中的应用提供科学依据。
1 材料与方法1.1 试验材料 试验所采用的酵母培养物来自酿酒酵母，购自浙江科峰生物技术有限公司，金霉素为兽用抗生素，购自当地动物医院。
1.2 试验日粮 仔猪基础日粮组成及日粮营养水平如表1所示。
1.3 试验设计 试验将300头21日龄仔猪随机分为3组，每组5个重复，每个重复20头仔猪，单栏饲养，其分组设计见表2。
酵母培养物对断奶仔猪生长性能、机体抗氧化能力和免疫功能的影响孙强东，朱爱民（盐城生物工程高等职业技术学校，江苏盐城 224051）[摘要]文章旨在研究酵母培养物在动物生产上的实际使用效果，试验选取断奶仔猪300头（21日龄断奶），随机分成3组，每组5个重复，每个重复20头仔猪，单栏饲养。
hydrochloride, oxytetracycline calcium and amoxicillin show extremely inhibited effect for Clostridium butyricum. Chlortetracycline hydrochloride and oxytetracycline calcium at concentrations of 50 mg/kg, 100 mg/kg and 150mg/kg have strong inhibited effect to Enterococcus faecalis. Eight different veterinary antibiotics which was tested in the experimentat in different concentrations are on inhibited effect to Yeast. In summary, probiotics should be avoided in combination with veterinary antibiotics that are extremely bacteriostatic.Keywords: Probiotics; Veterinary antibiotics; Antibacterial diameter; Inhibited effect（责任编辑：周会会）酵母水解物的不同添加方式对肉鸡生产性能及肠道组织形态的影响管秀界，刘 燕，王继苹，张亚丽，张 鑫*（辽宁禾丰牧业股份有限公司，辽宁沈阳 110866）摘 要：试验旨在研究酵母水解物的不同添加方式对肉鸡生产性能及肠道组织形态的影响。
试验选用900只1日龄AA 肉鸡，按照体重和性别随机分到3个处理组，每个处理6个重复，每个重复50只。
3个处理组分别为基础日粮组、1 kg/t 酵母水解物组（基础日粮+1 kg/t 酵母水解物）、5 kg/t 酵母水解物组（仅在1~10日龄基础日粮+5 kg/t 酵母水解物）。
饲料酿酒酵母
饲料酿酒酵母是一种在饲料生产中常用的微生物，其作用是将淀粉、糖类等碳水化合物发酵，产生酒精和二氧化碳，同时也可以产生一些副产品，如甘油、酯类等。
这些副产品可以作为动物饲料的营养成分，为动物提供能量和其他必需的营养物质。
饲料酿酒酵母在饲料工业中具有广泛的应用，主要涉及以下几个方面：
1.降低饲料成本：通过发酵技术将廉价的淀粉原料转化为高附加值的饲料营养成分，如酵
母细胞质、酵母蛋白等，降低了饲料成本。
2.提高饲料品质：饲料酿酒酵母发酵后产生的酵母蛋白富含氨基酸、维生素等营养成分，
可以改善饲料的营养价值，提高饲料的品质。
3.改善动物肠道健康：饲料酿酒酵母中含有丰富的膳食纤维和一些有益的微生物代谢产
物，可以促进动物肠道蠕动，改善肠道微生态平衡，提高动物健康水平。
4.提高动物生产性能：饲料酿酒酵母中的酵母蛋白和酵母多糖等成分具有免疫调节作用，
可以提高动物的免疫力和抗病能力，促进动物生长和生产性能的提升。
总的来说，饲料酿酒酵母在提高动物生产性能、降低养殖成本、改善饲料品质和动物肠道健康等方面具有重要作用。
未来随着发酵技术的不断发展和完善，饲料酿酒酵母的应用前景将更加广阔。
酿酒酵母培养物对反刍动物免疫抗病性及生产性能的影响李麦;周玉香
【期刊名称】《饲料工业》
【年(卷),期】2024(45)1
【摘要】酿酒酵母培养物具有提高反刍动物生产性能、调节免疫功能、调节瘤胃微生物促进消化等作用,在反刍动物上的应用日趋广泛。
近年来,科技工作者针对酿酒酵母培养物在畜牧业生产上的应用展开了大量的研究。
文章综述了酿酒酵母培养物对奶牛产奶量、乳品质、瘤胃发酵和免疫的影响,及对肉牛采食量、生长性能、抗病性的影响,以及对肉羊采食量、增重、免疫的影响,以期为酿酒酵母培养物在反刍动物上的应用提供技术参考。
【总页数】5页(P82-86)
【作者】李麦;周玉香
【作者单位】宁夏大学动物科技学院
【正文语种】中文
【中图分类】S816
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5.酿酒酵母培养物奶酵益-X6对奶牛生产性能和健康状况的影响
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Animal Feed Science and Technology142(2008)33–43Available online at Growth performance and carcass characteristics of Awassi lambs and Shami goat kids fed yeastculture in theirfinishing dietH.H.Titi a,∗,R.O.Dmour a,A.Y.Abdullah ba Department of Animal Production,Faculty of Agriculture,University of Jordan,Amman11942,Jordanb Department of Animal Production,Faculty of Agriculture,Jordan University of Science and Technology,P.O.Box3030,Irbid22110,JordanReceived25January2007;received in revised form18June2007;accepted25June2007AbstractTwo experiments were completed to examine effects of inclusion of a yeast culture(YC)to a diet based on barley grain and wheat straw on digestibility,growth and meat traits of Awassi lambs and Shami goat kids.Experiment1studied effects of YC on apparent digestibility of dry matter (DM),organic matter(OM),crude protein(CP),neutral detergentfiber(NDF),acid detergentfiber (ADF)and N balance in sheep,while experiment2studied effects on growth performance and carcass composition of lambs and kids.The same diet was used in both experiments and the YC was added to the diet of treated groups at the level of12.6kg YC/tonne of diet.Addition of YC had no effect on apparent digestibility of DM,CP and NDF,but it increased(P<0.05)digestibility of OM and ADF. No differences occurred in N intake,output or retention.Addition of YC did not affect growth rate, or DM intake,in both lambs and kids.YC supplementation to lambs reduced hot carcass weight,cold dressing proportion and total muscle/bone ratio,but increased empty digestive tract weight.There were no changes in back fat thickness,intermuscular fat of the leg muscle,and weights and proportions of carcass cuts.Measures of kids’carcass characteristics and quality also did not differ.Only cuts of leg and shoulder differed(P<0.05)when calculated as a proportion of the whole carcass cut.Results show that YC supplementation increased digestibility with no effect on growth,feed intake or feedAbbreviations:ADF,acid detergentfiber;ADG,average daily gain;DM,dry matter;FCR,feed conversion ratio;LW,live weight;NDF,neutral detergentfiber;OM,organic matter;YC,yeast culture∗Corresponding author.E-mail address:htiti@.jo(H.H.Titi).0377-8401/$–see front matter©2007Published by Elsevier B.V.doi:10.1016/j.anifeedsci.2007.06.03434H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43conversion ratio of fattening lambs and kids.However,YC supplementation reduced meat/bone ratio and tissue protein content,but increased fat content in carcasses of fattening Awassi lambs,but not in fattened Shami kids.©2007Published by Elsevier B.V.Keywords:Yeast;Digestibility;Growth performance;Carcass;Lambs;Kids1.IntroductionFeed is a major component of livestock farming and many experiments have been com-pleted to improve the nutritive value of low quality feeds utilized by ruminants.Utilization efficiency of somefibrous feedstuffs might be improved through utilization of biotech-nology,such as yeast culture(YC)supplements.The motivation for examining these alternatives comes from increasing consumer concern about the safety of chemical growth promoters in the animal feed industry,as well as the need for a safe food supply.Studies that have examined effects of YC have reported variable results.Some found that YC supplementation did not stimulate digestibility of DM,OM,CP,NDF,ADF,and/or N retention in lambs consuming total mixed rations(Adams et al.,1981;Angeles et al., 1998;Corona et al.,1999;Kawas et al.,2007a).In contrast,others have shown increased digestibility of CP,NDF,ADF and cellulose in dairy cattle(Wiedmeier et al.,1987;Erasmus et al.,1992;Wohlt et al.,1998)or steers(Plata et al.,1994;Cabrera et al.,2000).Yeast culture had has no effect on DM intake,live weight gain or feed conversion ratio of steers(Adams et al.,1981;Cole et al.,1992;Cabrera et al.,2000),midlactation dairy cows(Piva et al.,1993),orfinishing lambs(Kawas et al.,2007b).Others found that DM intake was higher in bulls fed YC,while live weight gain and feed conversion ratio did not differ between treated and control groups(Mutsvangwa et al.,1992).Erasmus et al. (1992)showed that YC increased DM intake of lactating dairy cows.Wehner et al.(1998) found that YC fed calves gained more weight than controls,but this did not reach statistical significance.Likewise,YC supplementation had no effect of on ADG of grazing growing steers(Cabrera et al.,2000)orfinishing lambs(Kawas et al.,2007b).Small ruminants constitute the majority of the ruminant population in developing coun-tries.Data available on feeding YC to small ruminants,such as kids,is scarce,and especially lacking with regard to carcass characteristics.Only one recent study was found in which carcass traits were evaluated,where Kawas et al.(2007b)showed that YC supplementation had no effect on slaughter or carcass traits offinishing lambs.Therefore,the objective of this study was to evaluate effects of a supplementary YC(Saccharomyces cerevisiae)culture to sheep and goat diets on nutrient digestibility,N balance,growth performance,and carcass composition and meat quality of fattened Awassi lambs and Shami goat kids.2.Materials and methodsTwo experiments were conducted,being a digestibility study and a fattening one. The same diet(Table1)was used in both experiments and it was offered as a totalH.H.Titi et al./Animal Feed Science and Technology142(2008)33–4335 Table1Ingredients and chemical composition of the diet used in experiments1and2g/kg S.E. Ingredients composition aBarley grain614.1Soybean meal133.5Wheat bran115.7Wheat straw117.0DiCalcium phosphate9.7Limestone 5.0Salt 4.0Vitamins/Mineral premix b 1.0Chemical composition(g/kg)DM926 1.3 OM947 1.5 CP168 5.6 aNDF282 3.7 ADF-ADF133 2.6a Dry matter basis.b Ruminant nutristar premix provides per kg:30,00,000IU vitamin A;10,00,000IU vitamin D3;10,000IU vitamin E;1600mg nicotinic acid;4000mg choline chloride;10,000mg DL-methionine;5000mg HCL-lysine; 90,000mg Fe;3000mg I;1000mg Cu;50,000mg Mn;50,000mg Zn;200mg Se;1,00,000mg Mg;30,000mg P; 10,3000mg Ca;11,200mg antioxidant(Endox),STAR INTERNATIONAL95520OSNY FRANCE.mixed ration(TMR).Two treatments were included in each experiment being the con-trol(C)that was not supplemented,and the treatment diet supplemented with YC. The YC was supplemented according to manufacturer recommendations at the level of12.6kg/tonne of DM(“XP”Yeast Culture,Diamond‘V’.Mills,Cedar Rapids, IA,USA).The guaranteed analysis provided by the manufacturer was not less than 120g/kg crude protein(CP),less than30g/kg crude fat and not more than65g/kg of crudefiber.The YC wasfirst hand mixed with the micro components mixture of the ration before being placed in the horizontal mixer for complete mixing with other TMR ingredients.Samples were collected after each mixing and kept frozen for later analysis.2.1.Experiment12.1.1.Animals and experimental procedureThe main objective of this study was to assess effects of adding YC on nutrient digestibil-ity coefficients and N retention of lambs.An in vivo digestibility experiment was used with 12intact male Awassi lambs of about150±10days of age and with an initial live weight (LW)of39.5±7.1kg at the beginning of the mbs were divided into two treatment groups of equal number according to LW and placed in individual metabolic cages equipped with a water container and meshedfloor.The study was completed for two consecutive experimental periods in a switch-over design.Each experimental period was15days in length,with9days for adaptation period and6days for sample collection. Lambs were fed ad libitum during the adaptation period and intake was restricted to0.9036H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43of voluntary intake on individual basis during the collection mbs were fed once daily at09:00h and water was available at all time.Feces and urine were collected daily before feeding.Daily fecal output was composited for each lamb within the treatment for the collection period,then thoroughly mixed,and a 0.10representative sample preserved for later analysis.Urine excreted by each lamb over 24h was collected in300ml of HCl solution(3.0N)to avoid N loss.A0.10sample of collected urine was transferred to a5l container for each animal daily and kept at4◦C for later chemical analysis.2.2.Experiment22.2.1.Animals and experimental procedureThis experiment was conducted to determine effects of YC supplementation of the diet on growth performance of Awassi lambs and Shami kids in terms of DM intake,average daily gain(ADG),and feed conversion ratio(FCR),and to determine its effects on carcass composition and quality.A total of48Awassi male lambs and48Shami male kids were used.Animals of each species were divided into two groups of equal number based on LW. Each group was then randomly divided into3pens of8animals/mbs were around 120±7days old and weighed27.8±4.52kg,while kids were about105±7days old and weighed20.5±5.63kg.Animals were kept in an open shaded barn for the duration of the experiment.The LWs were measured at the beginning of the experiment and every14 days thereafter before feeding.The experimental period lasted12weeks.Feed was offered for14days for adaptation and then on an ad libitum basis.Animals were fed the same diets that were fed in experiment1.Feed consumption was measured as the difference between the amount offered and residues.The amount offered was adjusted daily based on the previous day’s consumption.Clean water was offered ad libitum for the whole period.By the end of the fattening period,12lambs and12kids(6/treatment,2/pen),were ran-domly selected,slaughtered and dressed at a commercial slaughterhouse following normal commercial procedures.Non-carcass components were weighed and recorded.Full weights of the foregut and intestines were weighed with all ingesta included,while empty weights were collected after being emptied and washed under running tap water and allowed to drip.Dressing proportions were calculated on a cold carcass weight basis and expressed as a proportion offinal fasting LW.Body length was measured on the whole carcass as the distance from the point where the gambrel is inserted to the base of the neck.Carcasses were halved along the vertebral column mid line.Each side was divided into five commercial cuts(i.e.,shoulder,rack,loin,leg,and tail),and cuts from both sides of every carcass were weighed.Linear measurements were made on the surfaces of the cuts,including back fat thickness,rib eye area,width and depth.Measurements were on the cut surface between rib12and13utilizing a metal ruler.After weighing,dissection was completed as quickly as possible to avoid moisture losses.Cuts were dissected into the components:Total muscles(M.semitendinosus,M.semimembranosus,and M.biceps femoris);total bone weight(bone plus cartilage);total fat(subcutaneous and intramuscular). The muscle(M.semitendinosus)of the right leg cut of each carcass was used for chemical analysis and subsequent determination of meat quality(Kawas et al.,2007b).H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43372.3.Analysis procedureChemical analysis was according to AOAC(1990)procedures.Feed and fecal samples were ground by a Wiley mill(Arthur H.Thomas Co.,Philadelphia,PA,USA)through a 1mm screen and analyzed for DM in a forced air oven at100◦C for12h(method967.03). Urea and total N were determined using a Kjeldahl method of N determination using a Kjeltec1030Auto Analyzer following digestion(method976.06).Organic matter(OM) was also measured(method942.05).Concentrations of acid detergentfiber(ADF)and neutral detergentfiber(NDF)were determined according to Van Soest and Robertson(1980) using the ANKOM Fiber Analyzer(ANKOM Technology,Fairport,NY,USA).NDF was determined using sodium sulphite,heat stable alpha amylase and expressed inclusive of residual ash(aNDF).ADF was determined using cetyl trimethyl ammonium bromide and 1N H2SO4and expressed inclusive of residual ash(ADF).Chemical analysis of meat was according to the AOAC(1990)as specified above including analysis for ether extract(EE, method22.033).2.4.Statistical analysisData of both experiments were analyzed using the GLM option of SAS(2000).Means were analyzed using a least significant difference(LSD)method(Steel and Torrie,1986). The model of the fattening section included effects of treatment,species and treat-ment×species interaction in a2×2factorial design.Initial LWs were used as a covariate in the model utilized for LW.Pen was also in the model as the experimental unit for DM intake.The value for DM intake was the mean of three observations per treatment,while all other values were for individual animals.Carcass data was adjusted for fasting weight and cold carcass weight.Furthermore,week(period)was utilized in the model with a repeated measure design to study effects of YC supplementation on growth parameters throughout the experiment and initial BWs were used as a covariate for statistical analysis.3.Results3.1.Experiment1:Digestibility and N-retentionThere was no difference in DM intake(Table2),and only OM and ADF digestibilities for the treatment group were higher(P<0.05)than those for the controls.The N intake tended(P=0.08)to be higher for lambs fed YC,but there were no differences in total,fecal, or urinary N output between the control and YC supplemented groups.3.2.Experiment2:Fattening study3.2.1.Body weights,gain and feed intakeFinal BWs and average daily gain did not differ between control and YC supplemented groups(Table3).Average daily gain for lambs and kids as related to time of the feeding are in Fig.1.The DM intake also did not differ in lambs and kids fed the diet supplemented38H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43Table2Effect of feeding yeast culture(YC)supplemented diet to Awassi lambs on digestibility coefficient of nutrients and N balanceC YC S.E.M.P1 Body weight(kg)39.238.5 4.200.60 DM intake(g/day)1071112371.90.20 Digestibility coefficient(g/kg)Dry matter7387567.80.30 Organic matter773b793a7.00.04 Crude protein7317448.30.50 Neutral detergentfiber46848027.50.70 Acid detergentfiber358b439a21.20.02 N BalanceN intake(g/day)28.730.3 1.500.08 Fecal N outputg/kg43840524.50.30 g/day7.87.60.500.50 Urinary N outputg/kg56259524.60.80 g/day10.111.6 1.100.20 Total N outputg/kg intake62663431.10.20 g/day17.919.2 1.400.60 Ng/kg intake37436630.90.40 g/day10.911.1 1.300.40 a,b Means with different superscripts within the same row are different(P<0.05).with YC and those of the control group(Table3).As a result,feed conversion ratio did not differ between yeast supplemented and control lambs or kids.3.2.2.Carcass measurements and cutsYeast culture supplementation decreased cold dressing proportion and increased (P<0.05)empty digestive tract weight(Table4),but only in lambs.These changes were not associated with differences in weight of external and/or internal organs,or internal fat. Table3Growth,feed intake and feed conversion ratio of Awassi lambs and Shami goat kids after yeast culture(YC) supplementationLambs Kids P aC YC C YC S.E.M.T S T×S No.of animals24242424Initial BW(kg)27.827.620.020.20.600.500.100.20 Final BW(kg)49.749.932.532.10.800.020.040.60 Average daily gain(g/day)26126614914212.00.010.010.40 DM intake(g/day)313132885387431.00.700.010.80 Feed conversion ratio 5.4 5.3 6.1 6.50.400.100.400.10 a T:treatment effect,S:species effect.H.H.Titi et al./Animal Feed Science and Technology142(2008)33–4339Fig.1.Average daily gain of lambs and kids during fattening on the control and yeast supplemented diets. Lower dressing proportion of treated lambs would mostly be a result of increased weight of non-carcass,especially the digestive tract.Increased empty digestive tract weight could indicate increased DM intake and/or higher body fat.Prime carcass cuts(i.e.,leg,loin, rack,shoulder,and tail)did not differ for lambs or kids fed control or YC supplemented diets(Table5).However,only leg and shoulder cuts in kids were different(P<0.05)when expressed as a proportion of total carcass weight.Leg of the control kids was higher com-pared to that for YC supplemented ones,while the shoulder proportion was higher in YC supplemented kids.Table4Carcass characteristics and linear measurements of Awassi lambs and Shami kids as influenced by the yeast culture (YC)supplementationLambs Kids S.E.M.P fC YC C YC T S T×S No.of animals6666CharacteristicsFasting weight a(kg)42.342.137.738.00.500.800.010.30 Hot carcass weight(kg)23.0a20.8b21.121.80.700.200.600.01 Dressing proportion0.526a0.478b0.5460.562 1.200.300.040.03 HSF b weight(kg)8.18.7 5.6 5.90.300.100.050.50 LHKSLS c weight(kg) 1.5 1.7 2.1 2.10.100.300.020.10 Total fat d weight(kg)0.050.100.400.500.100.500.02 1.00 Empty digestive tract(kg) 2.1a 2.5b 3.6 3.20.200.600.030.03 Linear measurementsBody length(cm)96.198.917.9115.0 2.100.400.100.40 Fat thickness e(mm) 6.68.2 4.1 4.00.700.500.100.30 Rib eye width(mm)61.359.956.756.3 2.000.400.100.30 Rib eye depth(mm)29.129.226.725.60.900.700.200.90 a,b Means with different superscripts within the same row are different(P<0.05).a Average weight of6animals/treatment,adjusted to constant fasting weight.b HSF:weight of head+skin+feet.c LHKSLS:weight of liver+heart+kidneys+spleen+lung+sweetbread.d Fat weight:fat of heart+kidney+pelvic.e Over M.longissimus dorsi(eye muscle).f T:treatment effect,S:species effect.40H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43Table5Wholesale cuts of Awassi lambs and Shami kids as influenced by the yeast culture(YC)supplementation Lambs Kids P aC YC C YC S.E.M.T S T×S Legkg 6.1 5.9 6.3 6.10.200.300.100.50 Proportion0.2870.2830.321a0.302b0.700.050.100.03 Lionkg 2.2 2.3 2.3 2.30.10 1.000.800.50 Proportion0.1080.1070.1180.1130.500.800.500.50 Rackkg 2.0 1.9 2.1 2.20.100.500.400.30 Proportion0.990.930.1070.1090.500.500.300.30 Shoulderkg7.27.39.19.40.200.030.010.80 Proportion0.3580.3580.449b0.470a0.600.040.010.02 Tailkg 3.3 3.40.70.60.200.900.010.90 Proportion0.1490.1590.600.600.900.500.010.50 a,b Means with different superscripts within the same row are different(P<0.05).a T:treatment effect,S:species effect.3.2.3.Dissection and chemical compositionTotal muscle/bone(M/B)ratio(Table6)was lower(P<0.05)for YC treated lambs versus control,but there were no differences in kids.Proportions of protein content in lambs was Table6Physical dissection of leg cut and chemical composition of muscle of Awassi lambs and Shami kids as influenced by the yeast culture(YC)supplementationLambs Kids P aC YC C YC S.E.M.T S T×S Physical dissection of leg cutTotal muscle proportion0.6080.5890.6300.627 1.300.400.010.30 Total fat proportion0.2320.2260.1460.1560.900.600.010.80 Total bone proportion0.1580.1720.2150.2070.800.500.05 1.00 TM/B ratio b 4.0a 3.5b 2.9 3.00.200.100.010.04 S.coetaneous fat/total fat73.173.856.655.1 3.800.400.010.70 Intramuscular fat/total fat27.026.243.444.9 4.000.600.010.80 Chemical composition c,proportionMoisture0.2250.23.20.2260.2230.400.300.100.50 Crude protein0.823a0.79.4b0.8040.811 2.500.400.010.03 Ether extract0.137b0.171a0.1720.156 1.200.700.010.04 Ash0.0510.0470.0460.0490.300.300.100.30 a,b Means with different superscripts within the same row are different(P<0.05).a T:treatment effect,S:species effect.b Total muscle/bon ratio.c Leg muscle sample.H.H.Titi et al./Animal Feed Science and Technology142(2008)33–4341 lower(P<0.05),and ether extract was higher(P<0.05),when YC was supplemented to the diets.4.Discussion4.1.Experiment1:Digestibility and N-retentionAlack of digestibility differences with YC supplementation are consistent with others who reported that supplemental YC failed to improve digestion coefficients of different diet components in sheep or lambs(Adams et al.,1981;Andrighetto et al.,1993;Angeles et al., 1998;Kawas et al.,2007a),bulls and steers(Mutsvangwa et al.,1992;Cabrera et al.,2000) or lactating dairy cows(Arambel and Kent,1990).Cole et al.(1992)reported that lambs fed YC in their diets had numerically higher apparent DM and N digestibility.In our case,lambs were fed a highly digestible concentrate diet,which could have masked positive effects of YC supplementation on digestibility.Another possibility could be that the low forage quality prevented benefits.Roa et al.(1997)showed that high benefits can be obtained with good quality ck of response to YC with low quality diets has also been reported by Cabrera et al.(2000).The improved ADF digestibility is consistent with others who reported that using YC improved ADF digestibility in dairy cattle(Erasmus et al.,1992;Wohlt et al.,1998)or steers (Plata et al.,1994).This might be related to increased concentrations of cellulolytic bacteria in the rumen(Wiedmeier et al.,1987;Harrison et al.,1988).Wiedmeier et al.(1987)and Plata et al.(1994)suggested that adding a YC supplement can stimulate rumen fermentation by increasing the number and proportion of cellulolytic bacteria in the rumen.However, Harrison et al.(1988)reported that,although YC stimulated an increase in the number of cellulytic bacteria,the activity of these organisms was decreased.Results of N balance are consistent with those of Mutsvangwa et al.(1992)and Kawas et al.(2007a)who reported no effect of supplementing YC on N parameters in bulls and lambs.In contrast,lambs fed YC had higher N retention than control lambs(Cole et al., 1992).In our case,lambs were fed on a diet with adequate CP(168g/kg)which could be a reason for no effect of YC supplementation on digestibility or N balance.4.2.Experiment2:Fattening study4.2.1.Body weights,gain and feed intakeImproved growth with YC supplementation has been reported with steers(Adams et al.,1981;Cabrera et al.,2000),calves(Cole et al.,1992),bulls(El Hassan et al.,1996; Mutsvangwa et al.,1992),andfinishing lambs(Kawas et al.,2007b).Kawas et al.(2007b) reported that addition of YC improved weight gain in lambs fed low protein diets with no benefit with those fed high protein diets.In our case,the relative high diet CP content could have prevented effects of YC supplementation on growth rate.The relationship between YC supplementation and CP level in the diet suggested no beneficial effect of YC on DM intake at high CP levels,but that could improve DM intake of diets with low CP levels(Kawas et al.,2007b).42H.H.Titi et al./Animal Feed Science and Technology142(2008)33–43Reasons behind the different responses to YC supplementation between our study and those of others are not clear.Cole et al.(1992)reported that the YC can have beneficial effects on performance under some circumstances,but there seems to be considerable unexplained variability in response.This could be due to factors such as basal diet,viable cell numbers in the YC,amount of YC supplemented,type of forage fed,and feeding strategy(Piva et al., 1993;Cabrera et al.,2000;Kawas et al.,2007b).For example,there was a greater beneficial effect of YC with forage based diets versus high concentrate diets(Kawas et al.,2007b).4.2.2.Carcass measurements and carcass cutsCarcass measurements were adjusted to a constant fasting weight and to a constant carcass weight for non-carcass components.Very little published literature is available concerning effects of YC supplementation on carcass characteristics,especially with kids. However,similar results were reported with Mir and Mir(1994)who reported no effects of YC supplementation on dressing proportions of growing steers.Basiony et al.(1998) indicated that YC supplementation did not influence carcass characteristics of buffalo calves. Recently,Kawas et al.(2007b)showed that YC had no effect on hot and chilled carcass weights,or dressing proportions of lambs fed a high grainfinishing diet due to no differences in DM intake.Reason for similarity in carcass cuts could be due to similar growth and LW gain during our fattening period.4.2.3.Dissection and chemical compositionLower protein content of the leg in YC treated lambs could indicate increased fat content of leg muscle.Indeed fat content was higher in treated lambs.Higher fat content could be related to changes in ruminal fermentation and metabolic end products.Several stud-ies reported that adding YC to ruminant diets resulted in low acetate:propionate ratio in the rumen(Harrison et al.,1988;Erasmus et al.,1992).Moreover,Erasmus et al.(1992) suggested that this lower ratio results from increased propionate production.5.ConclusionsResults show species variability in response to YC supplementation.It also indicated that YC supplementation improved digestibility of components of NDF.However,YC did not influence growth rate,feed intake or feed efficiency in growing lambs or kids.Nevertheless, carcass characteristics of lambs were altered with YC supplementation.ReferencesAdams,D.C.,Galyean,M.L.,Kieshing,H.E.,Wallace,Joe D.,Finkner,M.D.,1981.Influence of viable yeast culture,sodium bicarbonate and monensin on liquid dilution rate,rumen fermentation and feedlot performance of growing steers and digestibility in lambs.J.Anim.Sci.53,780–789.Andrighetto,I.,Bailoni,L.,Cozzi,G.,Berzaghi,P.,1993.Effects of yeast culture addition on digestion in sheep fed a high concentrate diet.Small Rumin.Res.12,27–34.Angeles,C.S.C.,Mendoza,M.G.D.,Cobos,P.M.A.,Crossby,G.M.M.,Castrej,F.A.,parision of two commercial yeast cultures(Sccharomyces Cerevisiae)on ruminal fermentation and digestion in sheep fed on corn stover diet.Small Rumin.Res.31,45–50.H.H.Titi et al./Animal Feed Science and Technology142(2008)33–4343 AOAC,1990.Official Methods of Analysis,twelveth ed.Association of Official Analytical Chemists,Washington, DC,USA.Arambel,M.J.,Kent,B.A.,1990.Effect of yeast culture on nutrient digestibility and milk yield response in early-to-midlactation dairy cows.J.Dairy Sci.73,1560–1563.Basiony,A.Z.,Ragheb,E.E.,Metwally,H.M.,1998.Effect of lasalocid and Yea-Sacc supplementation on perfor-mance,digestibility and carcass characteristics of buffalo calves.Nutr.Abst.Rev.,ser.B70,3.Cabrera,E.J.I.,Mendoza,M.G.D.,Aranda,I.E.,Garcia-Bojalil,C.,B´a rcena,G.R.,Ramos,J.J.A.,2000.Saccha-romyces Cerevisiae and nitrogenous supplementation in growing steers grazing tropical pastures.Anim.Feed.Sci.Tech.83,49–55.Cole,N.A.,Purdy,C.W.,Hutcheson,D.P.,1992.Influence of yeast culture on feeder calves and lambs.J.Anim.Sci.70,1682–1690.Corona,L.,Mendoza,G.D.,Castrej´o n,F.A.,Crosby,M.M.,Cobos,M.A.,1999.Evaluation of two yeast cultures (Saccharomyces Cerevisiae)on ruminal fermentation and digestion in sheep fed a corn stover diet.Small Rumin.Res.31,209–214.El Hassan,S.M.,Newbold,C.J.,Edwards,I.E.,Topps,J.H.,Wallance,R.J.,1996.Effect of yeast culture on rumen fermentation,microbial proteinflow from the rumen and live-weight gain in bulls given high cereal diets.Anim.Sci.62,43–48.Erasmus,L.J.,Botha,P.M.,Kistner,A.,1992.Effect of yeast culture supplement on production,rumen fermenta-tion,and duodenal nitrogenflow in dairy cows.J.Dairy Sci.75,3056–6065.Harrison,G.A.,Hemken,R.W.,Dawson,K.A.,Harmon,R.J.,1988.Influence of addition of yeast culture sup-plement to diets of lactating cows on ruminal fermentation and microbial population.J.Dairy Sci.71, 2967–2975.Kawas,J.R.,Garc´ıa-Castillo,R.,Fimbres-Durazo,H.,Garza-Cazares,F.,Hern´a ndez-Vidal,J.F.G.,Olivares-S´a enz,E.,Lu,C.D.,2007a.Effects of sodium bicarbonate and yeast on nutrient intake,digestibility,and ruminalfermentation of light-weight lambs fedfinishing diets.Small Rumin.Res.67,149–156.Kawas,J.R.,Garc´ıa-Castillo,R.,Garza-Cazares,F.,Fimbres-Durazo,H.,Olivares-S´a enz,E.,Hern´a ndez-Vidal,G., Lu,C.D.,2007b.Effects of sodium bicarbonate and yeast on productive performance and carcass characteristics of light-weight lambs fedfinishing diets.Small Rumin.Res.67,157–163.Mir,Z.,Mir,P.S.,1994.Effect of the addition of live yeast(Saccharomyces Cerevisiae)on growth and carcass quality if steers fed high–forage or high grain diets and on feed digestibility and in situ degradability.J.Anim.Sci.72,537–545.Mutsvangwa,T.,Edwards,I.E.,Topps,J.H.,Paterson,G.F.,1992.The effect of dietary inclusion of yeast culture (Yea-Sacc)on patterns of rumen fermentation,food intake and growth of intensively fed buls.Anim.Prod.55, 35–40.Piva,G.,Belladonna,S.,Fusconi,Sicbladi,F.,1993.Effects of yeast culture on dairy cow performance,ruminal fermentation,blood components,and milk manufacturing properties.J.Dairy Sci.76,2717–2722.Plata,F.P.,Mendoza,G.D.,B´a rcena-Gama,J.R.,Gonz´a lez,S.,1994.Effect of a yeast culture(Saccharomyces Cerevisiae)on neutral detergentfiber digestion in steers fed oat straw based diets.Anim.Feed.Sci.Tech.4, 203–210.Roa,M.L.,Blrcena-Gama,J.R.,Gonzllez,M.S.,Mendoza,M.G.D.,Ortega,C.M.E.,Garcla,B.C.,1997.Effect of fiber source and yeast culture(Saccharomyces Cerevisiae1026)on digestion and the environment in the rumen of cattle.Anim.Feed Sci.Tech.64,327–336.SAS Inc.,2000.SAS User Guide Statistics,Version7edition.SAS Inc.,Cary,NC,USA.Steel,G.D.R.,Torrie,H.J.,1986.Principles and Procedures of Statistics,second ed.McGrow-Hill,USA.Van Soest,P.J.,Robertson,J.B.,1980.Systems of analysis for evaluatingfibrous feeds.In:Pigden,W.J.,Balch,C.C., Graham,M.(Eds.),Standardization of Analytical Methodology for Feeds.International Research Development Center Pub.No.134e,Ottawa,Canada.Wehner,G.R.,Brokaw,L.,Gamett,J.E.,Zidon,J.,1998.Effect of yeast culture inclusion in ad libitum trace mineralized salt on cow and calf performance.J.Anim.Sci.(Suppl.1),34.Wiedmeier,R.D.,Arambel,M.J.,Walters,J.L.,1987.Effect of yeast culture and Aspergillus oryzae fermentation extract on ruminal characteristics and nutrient digestibility.J.Dairy Sci.70,2063–2068.Wohlt,J.E.,Corcione,T.T.,Zajac,P.K.,1998.Effect of yeast on feed intake and performance of cows fed diets based on corn silage during early lactation.J.Dairy Sci.81,1345–1352.。
