脂肪水平对早期断奶犊牛生长性能及血清生化指标的影响

早期断奶犊牛饲喂不同脂肪含量代乳品,研究脂肪水平对犊牛生长性能、血清生化指标及饲料进食量的影响,为犊牛生长规律和脂肪需要提供科学依据,为实际生产中犊牛早期断奶和培育提供技术指导。试验选取12头新生荷斯坦公犊牛,分为EE9、EE13、EE17 3组,每组４头,分别饲喂蛋白质水平相同、脂肪含量为9%、13%及17%的3种代乳品。每日记录犊牛开食料的采食情况,并于犊牛10、20、30、40、50、60日龄清晨空腹测定犊牛体重及体尺指标,同时采集犊牛的血液样本进行分析。研究结果表明,3组犊牛哺乳期的饲料日进食量分别为706.9、666.9、569.3 g;10~60日龄的平均日增重分别为498、544、488 g,EE13组犊牛日增重高于EE9、EE17组的犊牛;犊牛60日龄时,EE13组犊牛的体高、体斜长及管围均高于其它2组。血清尿素氮、血糖、甘油三酯的水平不受代乳品脂肪含量的影响,但日龄对哺乳期犊牛甘油三酯含量的影响差异显著(P<0.05)。随日龄的增加,犊牛的生长速度和饲料的进食量逐渐增加,低脂肪的代乳品(EE9)不能满足犊牛的能量需要,高脂肪的代乳品（EE17）抑制了犊牛对开食料的采食量,饲喂脂肪含量13％的代乳品（EE13）对犊牛生长发育优于其它2组。脂肪含量对犊牛血清生化指标的影响不显著。     

Influence of Urea Alone or Combined with Fish Solubles,Fish Meal,or Feather Meal in Liquid Supplement with and Without L-Carnitine on Performance and Ruminal and Metabolic Parameters of Weanling Calves

Using growing calves (n = 368) grazing mature forage in three 84-d experiments, one objective was to compare the effects of feeding molasses-based liquid supplements containing urea (U) alone or combined with fish solubles (FS), fish meal (FM), or feather meal (FE) on performance, and blood metabolites. Another objective was to evaluate the effects on these criteria of adding carnitine to these supplements to provide 1 g·h⁻¹·d⁻¹ L-carnitine. Including FM or FE in the mixture improved (P<0.05) supplement consumption in two experiments and improved growth rate in all experiments. Carnitine improved the growth rate when U was the only protein source, but reduced growth rate when FM was included in the liquid supplement (P<0.05). During the growth phase, plasma ammonia N (PAN) was higher (P<0.05) when U was the only protein source as compared with FM or FE. Carnitine did not influence these metabolic parameters. During the metabolic phase of each experiment, calves similar to those used in the growth phase were dosed via stomach tube with 3 g liquid supplement/kg BW. Ruminal and blood samples were collected at 0, 0.5, 1, 2, and 4 h after dosing. Ruminal ammonia N, PAN, and plasma urea N (PUN) concentrations were higher (P<0.05) when calves were dosed with U or FS supplement than when dosed with FM or FE supplements. Calves dosed with liquid supplement containing carnitine had lower (P<0.05) concentrations of ruminal ammonia N and PAN. Carnitine reduced (P<0.05) PUN in one experiment and increased (P<0.05) PUN in another. Branched-chain volatile fatty acids were increased (P<0.05) by dosing with FS or FM supplements. Including ruminally undegradable protein sources (FM or FE) in liquid supplement improved intake and performance and was related to reduced ruminal ammonia N, PAN, and PUN. Carnitine fed in liquid supplement also reduced ruminal ammonia N and PAN concentrations.     

断奶应激对犊牛血液中代谢物和激素的影响

为研究断奶对犊牛的影响,本试验选择体重和出生日期接近的黑白花公犊牛12头,在55日龄对犊牛进行断奶,饲喂全混合日粮。分别在断奶的第-1(55日龄)、0、1、4、7和14 d采集血液,观测血液中代谢物和激素含量的变化情况。研究结果表明,断奶过程中,血清中葡萄糖、总蛋白、胆固醇及血浆中胰岛素含量变化显著(P<0.05),血清中甘油三酯、免疫球蛋白和血浆醛固酮含量变化不显著(P>0.05)。血液中的急性蛋白含量在断奶过程中变化明显,断奶后含量升高(P<0.05)。     

Effect of Injectable Iron-Dextran on Dairy Calves and Lambs

Ten Holstein calves, 10 Jersey calves, 7 single lambs, and one lamb from each of ten sets of twins were injected with an iron-dextran solution shortly after birth. These were paired with an equal number of untreated animals that formed the control groups. Percentage of hemoglobin and body weights were recorded periodically up to 16 weeks of age for the calves and 21 weeks for the lambs.

Percentage of hemoglobin in the blood of treated calves was generally higher than that of untreated calves but body weights between groups were not significantly different. In the lambs there was no significant difference in percentage of hemoglobin or body weights between the treated and control groups. The results indicate that under the confined system of management as outlined, there was no advantage in administering iron-dextran to young calves or lambs.

     

黄芪对育肥绵羊生长及产肉性能的影响

为探寻育肥绵羊日粮中黄芪(Astargalus membranaceus)适宜的添加量,将36只3月龄体重相近广灵大尾羊公羔随机分成6组,对照组、I、II、III、IV和V处理组分别喂给基础日粮+0%,0.5%,1%,1.5%,2% 和3%黄芪。试验期70 d,考察其生长及产肉性能。结果显示:试验结束时II组活体重显著高于对照组、III组和IV组(P<0.05),极显著高于V组(P<0.01)。II组绵羊30 d和60 d日增重显著高于其他处理组和对照组(P<0.05),II组料重比极显著低于IV组和V组(P<0.01),显著低于C组和III组(P<0.05)。II组胴体重和净肉重极显著高于 IV组、V组和对照组(P<0.01),显著高于I组和III组(P<0.05);胴体分割后II组羊肋脊排和带臀腿重显著高于其他处理组和对照组(P<0.05)。育肥绵羊日粮中添加1%黄芪可显著提高日增重,提高饲料利用率,增加优质肉块的比例。     

限时放牧对苏尼特羔羊生长性能及主要消化器官发育的影响

为研究限时放牧对苏尼特羔羊生长性能及肉品质的影响,试验选取30只体重相近的4月龄苏尼特去势公羔作为试验动物,将其随机分成5组,每组6只。试验第Ⅰ组完全舍饲,不放牧,补饲精料500g;Ⅱ、Ⅲ、Ⅳ组放牧加补饲,放牧时间分别为2、4、8h,分别补饲精料500、250、250g;第Ⅴ组为全天放牧,放牧12h,不补饲。试验结束后羔羊全部屠宰,取相应组织样分析处理。结果表明:放牧加补饲有利于提高日增重,但放牧时间过长日增重反而降低(第Ⅳ组);第Ⅲ组羔羊的小肠长度、四胃总重量和四胃所占比例均高于其他各组,且四胃所占比例显著高于第Ⅰ组(P<0.05),其中瘤胃的发育好于其他各组。     

Effect of Supplementary Feeding on Growth Performance and Ruminal Fermentation in Winter Season Grazing Sheep

The experiment was conducted with twenty-four grazing sheep divided into 3 experimental groups on the basis of body weights, i.e. control, optimal and non-optimal groups to study the effect of optimized supplementation on growth performance and rumen fermentation characteristics of grazing sheep in winter. The sheep in control were grazing only, whereas the grazing sheep in the optimal were supplemented with 250 g of an optimal forage mix and 404 g of concentrate1. The animals in non-optimal were supplemented with 465 g of concentrate 2. Weight gain rate in the optimal increased by 1.2% and 15.3 % as compared to that of the non-optimal and control group, respectively. Ruminal fermentation parameters were not significantly different between the optimal and non-optimal groups, however,they were significantly improved compared to the control. These results indicated that optimized supplementation strategies in winter were beneficial for markedly improving growth performance and rumen fermentation characteristics of grazing sheep.     

代乳粉对羔羊生产性能及血液生化指标的影响

本文旨在研究代乳粉对羔羊生产性能和血液生化指标的影响,并优选出适宜的羔羊代乳粉营养水平和稀释比例。选择80只健康的小尾寒羊羔羊,采用单因子试验设计,将羔羊随机分为4组进行试验。初生羔羊吃足初乳,于5天后分组,采用逐渐替代法,将母乳转换成3种不同营养水平的代乳粉,分别以一定的稀释比例哺喂3组羔羊,另1组为对照组(喂纯羊乳)。结果表明:①饲喂代乳粉对各组羔羊的死亡率无显著影响。②试验1组的平均日增重(ADG)为193 g,明显高于对照组的151.25 g和试验3组的107 g,差异显著(P<0.05);而试验2组的平均日增重为160.5 g,与其他3组无明显差异(P>0.05)。③血液指标中,血糖(Glu)值以试验1组最高,为3.84 mmol/L,明显高于对照组和其他2组(P<0.01);试验2组的血清尿素氮(BUN)值为16.89 mg/dL,极显著地高于对照组的9.99 mg/dL和试验3组的8.76 mg/dL(P<0.01),显著高于试验1组(P<0.05);各组中血清白蛋白(ALB)含量比较接近,无显著差异(P>0.05);总蛋白(TP)含量试验1组最高为52.26 g/L,极显著高于对照组和试验3组(P<0.01),而与试验2组相比差异不显著(P>0.05)。早期断奶羔羊平均每只每日进食的消化能和粗蛋白分别为9.21 MJ、106.92 g,哺喂营养含量和稀释比例适宜的代乳粉(试验1组)能促进早期断奶羔羊的生长发育。     

The Anthelmintic Activity of Cambendazole in Calves and Lambs

Tests were carried out on the efficacy of Cambendazole (5-isopropoxy carbonylamino-2-(4-thiazolyl) benzimidazole) against lungworm and gastrointestinal parasites of calves and lambs. Against Dictyocaulus viviparus the compound was highly effective (80%) against mature worms at levels of 35 mg/kg and over and immature “arrested” worms at 60 mg/kg (71% efective).

In the Calves the compound was very effective (90 to 99%) against adult Haemonchus placei, Ostertagia spp., Trichostrongylus axei and Cooperia oncophora at all levels tested (15, 20, 25, 30, 40 and 60 mg/kg). Against adult Nematodirus spp. dosages of 30, 40 and 60 mg/kg were 81%, 94% and 99% effective respectively

Against arrested Ostertagia spp. larvae, a dosage of 60 mg/kg was 90% effective. Immature stages of Cooperia spp. were susceptible at all levels used but those of Nematodirus spp. required levels of 60 mg/kg for 99% removal.

In the lambs the compound was highly effective against immature and mature nematodes when given orally at all levels tested from 15 mg/kg to 30 mg/kg. Significant reductions (81%) in Moniezia expansa scolices were also observed at dosages from 15 mg/kg to 30 mg/kg.

     

Influence of Energy and Protein Supplementation on Growth Rate,Empty Body Composition and Ruminal and Blood Metabolites of Goat Kids Fed Hay Diets

A comparative slaughter experiment was conducted with 28 Spanish kids (BW = 20.6 kg) fed a hay-based diet to determine the effects of supplemental energy and protein on growth rate, body composition, and ruminal and blood metabolites. After 84 d, kids were harvested, digesta contents removed and empty body weighed and ground. Samples were freeze-dried and analyzed for DM, CP, ether extract, ash, and gross energy. All kids had increased BW gains. However, unsupplemented kids lost empty BW and weight of all body components except ash. Kids supplemented with energy or protein increased (P<0.05) empty BW, body water, protein, fat, ash, and gross energy when compared with unsupplemented kids. The percentages of body water and ash decreased (P<0.05) when supplemental energy or protein was fed. The percentage of body protein was reduced (P<0.05) by supplemental energy and unaffected (P=0.81) by supplemental protein. Supplemental energy reduced (P<0.05) ruminal acetate and increased (P<0.05) propionate and butyrate. Supplemental protein increased (P<0.05) concentrations of ruminal ammonia N, plasma urea N, and all ruminal volatile fatty acids. Regression equations suggest that intake of 144 kcal of ME and 6.0 g of CP per kilogram of empty BW^0.75 are necessary to maintain empty BW.     

延胡索酸二钠对早期断奶羔羊生长性能、瘤胃发酵功能及胃肠道发育的影响

本研究旨在探讨饲粮中添加延胡索酸二钠对早期断奶羔羊生长性能、瘤胃发酵功能及胃肠道发育的影响。试验选用30只(50±5)日龄、体重为(25±2)kg的公羔,随机分为3组,每组10只。对照组饲喂基础饲粮,试验组在对照组的基础上添加0.5%和1.0%的延胡索酸二钠。试验期70 d。结果显示:1)饲粮添加延胡索酸二钠提高了平均日增重,其中1.0%组显著高于对照组(P0.05)。2)延胡索酸二钠未显著影响瘤胃液p H(P0.05),而显著降低了氨态氮浓度(P0.05);延胡索酸二钠极显著降低了瘤胃液乳酸浓度(P0.01);1.0%组瘤胃液总挥发性脂肪酸、乙酸和丙酸浓度显著高于对照组(P0.05)。3)试验组小肠绒毛高度均高于对照组,其中0.5%组羔羊的十二指肠、空肠、回肠的肠绒毛高度分别显著增加了30.3%、30.6%、46.1%(P0.05);试验组的十二指肠绒毛高度/隐窝深度显著大于对照组(P0.05),其中0.5%组的绒毛高度/隐窝深度较对照组增加了58.6%;0.5%和1.0%组羔羊的瘤胃壁乳头高度分别比对照组提高139.84和156.74μm(P0.05);试验组瘤胃壁乳头密度与对照组比较无显著差异(P0.05)。结果表明,添加延胡索酸二钠显著提高了羔羊的生长性能,促进了早期断奶羔羊瘤胃及肠道的发育。     

宰前休息方式对猪福利、血液成分及肉质的影响

选取体质量约为100 kg、氟烷基因型为NN的长×大二元杂交猪60头,随机分为3组:不休息组,休息3 h组,休息3 h+玩具组,公母各半.根据评分标准分别记录休息过程中猪的精神状况.放血时收集血样,用于分析血浆中皮质醇、促肾上腺皮质激素(ACTH)浓度,乳酸脱氢酶、肌酸激酶活性,乳酸、血糖浓度;添加EDTA-K<,2>抗凝剂的血样用于血细胞分析.同时在放血时,测定血温.屠宰后.测定背最长肌24 h滴水损失;背最长肌(LM)、半膜肌(SM)45 min以及24 h的pH、色值、导电率.结果表明:①休息3 h+玩具组在3个时间段的精神评分要极显著高于休息3 h组,随着时间的延长猪都表现出趋于平静的趋势;②休息3 h+玩具组和休息组3 h组在皮质醇、促肾上腺皮质激素要显著低于不休组(P<0.05),相反乳酸脱氢酶、肌酸激酶要显著高于不休息组(P<0.05),而休息3h+玩具组与休息3 h组差别不显著(P<0.05);③3个休息处理组在肉质指标上没有出现显著差别(P<0.05);④休息3 h+玩具组、休息3 h组在红细胞数(RBC)、血红蛋白含量(HGB)均要显著低于不休息组(P<0.05);休息3h+玩具组在白细胞数(WBC)上显著高于不休组(P<0.05);休息3 h组的淋巴细胞绝对值(W-SCC)显著高于不休息组(P<0.05);而休息3 h+玩具组与休息3 h组在所有的免疫指标上都没有显著差异(P>0.05).根据上述的结果显示,宰前一定要让猪有一个休息的过程,这种措施能有效缓解猪的应激,并能恢复其免疫能力;在休息的过程中,添加部分福利玩具,至少对猪的精神状态有明显的好处.     

围产期补饲对放牧蒙古羊母羊泌乳性能及羔羊生长性能的影响

旨在研究围产期补饲精补料对戈壁地区妊娠期放牧蒙古羊母羊增重、血液生理生化指标、泌乳性能以及羔羊生长性能的影响。选取20只体况相近、平均体重为（60±5.54）kg的妊娠期蒙古羊母羊, 按平均体重分为试验组和对照组, 每组10只。对照组按照传统补饲方法补饲玉米300 g/（只·d）, 试验组补饲精补料300 g/（只·d）。补饲试验预饲期5 d, 正饲期60 d。测定试验母羊初始体重和补饲试验末体重, 计算总增重;补饲试验结束时, 采集试验母羊血液样本, 测定血液常规指标和血清生化指标;从产后第15天起使用差重法测定母羊泌乳量, 持续到产后第85天;测定羔羊的初生重、90日龄重, 计算羔羊在90日龄内的日增重。利用统计学方法对对照组和试验组的上述指标进行分析。结果表明, 在补饲试验期间, 试验组母羊与对照组母羊的总增重差异不显著（P>0.05）, 试验组母羊的体重减少幅度比对照组母羊低1.71%;试验组母羊的各项血液常规指标和血清生化指标与对照组母羊相比差异均不显著（P>0.05）;整个泌乳期试验组母羊的泌乳量都高于对照组母羊, 其中, 产羔后75 d和85 d, 试验组母羊的泌乳量显著（P<0.05）或极显著（P<0.01）高于对照组母羊;与对照组羔羊相比, 试验组羔羊的90日龄体重和90日龄内日增重有所提高（P>0.05）。综上提示, 围产期补饲精补料能够提高放牧蒙古羊母羊的产后泌乳量, 并且有助于提升羔羊日增重。     

不同断奶日龄羔羊瘤胃组织显微及超微结构比较

试验通过比较不同断奶日龄的湖羊羔羊瘤胃组织结构的差异,特别是瘤胃乳头超微结构变化,旨在为羔羊适宜断奶日龄的确定提供瘤胃生长发育的依据。选择新生湖羊羔羊24只（初生重：2.80 kg±0.08 kg）,随机分为3组,每组8只,分别为30日龄早期断奶组（EEW-30）、45日龄早期断奶组（EW-45）和60日龄常规断奶组（NW-60）。在各断奶日龄及75日龄时每组分别屠宰4只羔羊,测定体重及瘤胃空重,计算瘤胃相对重量;采集瘤胃组织进行显微及超微形态学测定。结果显示：①EEW-30组羔羊断奶体重极显著低于NW-60组（P<0.01）,而EW-45组与NW-60组断奶体重无显著差异（P>0.05）;75日龄时3组羔羊的体重无显著差异（P>0.05）。各组羔羊瘤胃相对重量与其体重变化规律相同。②光镜下可见：断奶时,EEW-30组瘤胃壁厚度极显著低于NW-60组（P<0.01）,EW-45组与NW-60组无显著差异（P>0.05）;75日龄时,EW-45组羔羊瘤胃壁厚度显著高于NW-60组（P<0.05）。断奶时EEW-30组瘤胃乳头较短小,极显著短于NW-60组（P<0.01）,EW-45组也显著短于NW-60组（P<0.05）。断奶时瘤胃乳头宽度和面积在3组间差异均不显著,在75日龄时也无显著组间差异（P>0.05）。③扫描电镜观测结果显示：EEW-30组断奶时单位面积瘤胃微乳头（ruminal micro-papillae）数量极显著低于NW-60组（P<0.01）,而EW-45与NW-60组间无显著差异（P>0.05）;75日龄时,3组羔羊单位面积瘤胃微乳头数量无显著差异（P>0.05）。上述试验结果显示,断奶时羔羊瘤胃形态结构在EEW-30与NW-60组间差异明显,而EW-45与NW-60组较为接近,瘤胃微乳头状结构也呈相同变化趋势。提示45日龄时断奶较为适宜。     

亚麻籽对育肥期肉牛生长性能和血液指标的影响

[目的]研究在日粮中添加亚麻籽对肉牛生长性能和血液指标的影响。[方法]选择体重接近的西杂牛32头,采用单因素试验设计,随机分为4组,每组8头。[结果]表明:日粮中随着亚麻籽添加水平的提高,日增重由1.59kg/d提高到1.74kg/d,提高9.43%(P0.05);料重比由5.31降低到4.93,相对提高7.16%;粗脂肪的表观消化率显著提高(P0.05);血清中游离脂肪酸随着添加比例的提高而升高(P0.05),血清尿素氮、甘油三酯、胆固醇含量随添加水平的提高均有降低趋势。试验组经济收入分别比对组照多收入0.04元,1.41元,1.64元。[结论]①提高日粮中亚麻籽的水平可以显著提高肉牛的生长性能;②可以显著降低血清胆固醇和甘油三酯的含量。③从经济效益的角度和各种指标的综合分析来看,适宜的亚麻籽添加水平为10%～15%。     

营养条件对荷斯坦公犊生长发育及血液中激素水平的影响

选择同期出生的48头中国荷斯坦公犊,在其1月龄时随机分为4组,Ⅰ、Ⅱ、Ⅲ、Ⅳ组分别采用全乳、全乳+精料、代乳粉(料)和精料(对照组)进行饲养,研究不同日粮饲喂犊牛对其生长发育的影响。结果表明:Ⅰ组的体重在2～6月龄时均显著高于Ⅲ、Ⅳ组(P<0.05);尽管Ⅲ组的体重和日增重在2月龄时显著低于另3组(P<0.05),但到6月龄时,其日增重达到1.35kg/d,且与Ⅰ组无显著差异(P>0.05)并明显高于Ⅳ组(P<0.05)。说明代乳料饲喂的犊牛在后期的生长能够接近全乳饲喂的水平。4组间体长指数和髋胸指数在分组饲养后的开始几个月里存在显著性差异(P<0.05)。体重、日增重以及多数体尺指标均与T3和GH浓度呈显著(P<0.05)或极显著(P<0.01)相关,T4和INS浓度仅与体斜长、体长指数和髋胸指数呈显著(P<0.05)相关,且日增重仅与T3浓度有极显著相关(P<0.01)。Ⅰ组犊牛的血清中T3浓度在2～6月龄时均显著高于Ⅳ组(P<0.05),且除6月龄以外,其余各月龄时均显著高于Ⅲ组(P<0.05)。说明血清中T3浓度可能是能反映并监控荷斯坦犊牛生长发育和营养情况的重要指标。     

前期营养水平对羔羊两阶段育肥效果的影响

试验旨在研究前期营养水平对羔羊两阶段育肥效果的影响。选用蒙古羔羊(羯羊)80只,随机分为对照组(CG)、中等受限组(RG1和RG2)和严重受限组(RG3)4个处理组。进行营养限制期60 d 和补偿期90 d 的羔羊生长育肥试验。限制期4个组日粮对应能量(ME)、氮(CP)水平分别为10.88、10.88、9.41、8.62 MJ/kg和15%、10%、10%、5.7%。补偿期各组饲喂同一能氮水平日粮(ME:9.75 MJ/kg;CP:12%)。研究羔羊在限制期和补偿期体重、日增重、屠宰率、净肉率、肉骨比、胴体产肉率、眼肌面积和GR值的变化规律。结果表明,限制期结束时,CG组羔羊的体重显著高于RG1和RG2组(P＜0.05),极显著高于RG3组(P＜0.01),CG组羔羊的屠宰率、净肉率、肉骨比、胴体产肉率、眼肌面积和GR值明显高于受限组。补偿期结束时,RG3组羔羊日增重显著高于CG组(P＜0.05),受限组羔羊体重、屠宰率、净肉率、肉骨比和胴体产肉率有逐渐接近CG组的趋势,且4个组羔羊的眼肌面积和GR值差异不显著(P＞0.05)。因此,蒙古羔羊在限制期受到日粮中不同能氮水平限制后,经过补偿期后体重表现出不同程度的补偿效应,而且日粮中蛋白质的限制比能量的限制对补偿生长的负影响更大。在限制期蛋白质的限制影响羔羊的产肉性能较明显,补偿期能量的补充更重要。     

三元杂交肉用犊牛育肥效果试验报告

皮西本F1、利西本F1三元杂种犊牛在育肥场集中舍饲育肥180 d,头均增重158.25 kg和152.25 kg,日增重879.15 g和845.78 g,在农户一般饲养条件下育肥头均增重114.25kg和103.5kg,日增重634.68 g和574.95 g,在不同的饲养管理条件下育肥效果差异极显著(P<0.01),但在相同的饲养管理条件下,皮西本F1和利西本F1不同三元杂交组合间育肥效果差异不显著(P>0.05)。通过该试验说明三元杂种犊牛适于集中舍饲育肥,农户作为我市重要的育肥牛源基地,只有加强饲养管理采用综合配套技术措施,才能得到理想的育肥效果。     

异丁酸对犊牛瘤胃及小肠黏膜基因表达的影响

本试验旨在研究饲粮补充异丁酸对断奶前后犊牛瘤胃及小肠发育相关基因表达的影响。选取平均体重(40.0±0.2)kg、发育正常、30日龄的中国荷斯坦公犊牛36头,随机分为4组,对照组饲喂基础饲粮,试验组分别在基础饲粮的基础上添加异丁酸3、6和9 g/d。分别于45、60(断奶)、90日龄每组屠宰3头并采集瘤胃及小肠黏膜组织样品,通过实时荧光定量PCR技术检测生长激素受体(GHR)、胰岛素受体(INSR)、3-羟基-3-甲基戊二酰辅酶A合成酶1(HMGCS1)和钠-葡萄糖共转运载体1(SGLT1)的mRNA表达量。结果表明:犊牛体重和GHR、INSR、HMGCS1 mRNA的表达量均随着犊牛日龄的增长而出现显著增长(P0.05),而SGLT1mRNA的表达量在断奶前后随着日龄的增长先下降后增长,变化显著(P0.05)。45和60日龄时,犊牛体重在9 g/d异丁酸组显著高于对照组(P0.05),但与6 g/d异丁酸组差异不显著(P0.05)。各日龄6和9 g/d异丁酸组瘤胃和小肠各部位GHR、INSR、HMGCS1 mRNA的表达量均高于对照组,且这2组之间差异不显著(P0.05)。添加异丁酸对45日龄和90日龄犊牛小肠各部位SGLT1 mRNA的表达量没有显著影响(P0.05);60日龄6和9 g/d异丁酸组十二指肠SGLT1 mRNA表达量显著高于对照组和3 g/d异丁酸组(P0.05),9 g/d异丁酸组空肠近端、空肠远端和回肠SGLT1 mRNA表达量显著高于对照组(P0.05),但与6 g/d异丁酸组差异不显著(P0.05)。综合以上结果,饲粮中补充异丁酸能够促进犊牛生长和瘤胃及小肠黏膜的发育,本试验条件下其适宜添加量为6 g/d。     

日粮添加蛋氨酸对幼兔生长发育、免疫性能及血液生化指标的影响

选择100只断奶新西兰兔,随机分成5组,在日粮中分别添加不同水平的蛋氨酸（0、0．2％、0．4％、0．6％、0．8％）,研究其对生长性能、氮代谢、免疫性能及血液生化指标的影响。结果表明：日粮添加蛋氨酸能显著提高日增重和饲料转化率（P〈0．05）,添加蛋氨酸0．4％时,日增重和料重比达最佳水平．分别为30．8g、3．29：1;蛋氨酸水平对氮代谢的影响差异不显著（P〉0．05）;蛋氨酸对胸腺指数的影响差异显著（P〈0．05）,当添加量为0．4％时,胸腺指数达到最大,但是对肝脏指数和脾脏指数无显著影响（P〉0．05）。对免疫球蛋白A、G、M含量也无显著影响（P〉0．05）;蛋氨酸对血清中总蛋白、白蛋白和血清尿素氮的含量无显著影响（P〉0．05）．