不同蛋白水平日粮对武定鸡生长性能及血液生化指标的影响

选用192只平均体重接近的云南武定鸡,随机分为3组,分别饲喂3种不同的蛋白水平日粮(17.50%、18.00%和19.50%),探讨日粮蛋白水平对30～60日龄云南武定鸡生长性能及血液生化指标的影响。试验结果表明,增加日粮蛋白水平可以提高日增重和降低料重比,提高生长性能,但差异不明显(P>0.05);对血液生化指标中的瘦素、T3和胆固醇含量有显著影响(P<0.05),对其它各项血液生化指标均无显著影响(P>0.05)。     

日粮蛋白水平对藏猪生产性能和血清生化指标的影响

本试验旨在氨基酸平衡日粮的基础上,探讨不同蛋白水平日粮对藏猪生产性能和血清相关生化指标的影响。试验选择健康、体重接近的2月龄藏猪48头,随机分为4组,分别饲喂蛋白质水平为16%(对照组)、14%(试验1组)、12%(试验2组)和10%(试验3组)的氨基酸平衡日粮,每组3个重复,每个重复4头藏猪。整个试验进行6个月。结果表明:与对照组相比,试验2组显著降低了藏猪6月龄的平均体重(P0.05),试验3组显著降低了藏猪4月龄和6月龄的平均体重(P0.05),但最终8月龄时各处理组藏猪的平均体重无显著差异(P0.05);此外,不同蛋白水平日粮对藏猪平均日增重、平均日采食量和料重比无显著性影响(P0.05);藏猪血清中尿素氮含量随日粮蛋白质水平的降低而下降,且各处理组间均有显著差异(P0.05);与对照组相比,低蛋白水平日粮(12%和10%)会显著降低藏猪血清中血糖和Ig M含量(P0.05),但对Ig G含量无明显影响(P0.05)。综上所述,藏猪对低蛋白日粮具有良好的适应性,12%和10%蛋白水平日粮不会影响藏猪最终的生产性能,但会降低藏猪的免疫功能,藏猪日粮中蛋白水平保持在14%是一个合适的选择。     

日粮蛋白水平对小尾寒羊羔羊生长性能、营养物质表观消化率、氮排放和血清生化指标的影响

本试验旨在研究不同蛋白水平日粮对小尾寒羊公羔生长性能、营养物质表观消化率、氮排放和血清生化指标的影响,以期为小尾寒羊羔羊低蛋白科学饲养提供理论依据.试验选取 36只体重相近 [(18.05 ± 1.36) kg]、健康状况良好的3月龄小尾寒羊公羔,随机分为3组,每组12只.Ⅰ组饲喂低蛋白水平日粮(12.00%),Ⅱ组饲...     

补饲不同蛋白水平日粮对北川白山羊生产性能和屠宰性能的影响

本试验旨在研究放牧补饲不同蛋白水平日粮对北川白山羊生产性能和屠宰性能的影响。选择60只(6月龄)北川白山羊作为研究对象,随机分成4组,即14%蛋白组、16%蛋白组、18%蛋白组和对照组(不补饲),每组15只,测定生产性能、血液生化指标和屠宰性能。结果显示:补饲组北川白山羊平均日增重、血清总胆固醇、尿素氮含量、葡萄糖含量、谷草转氨酶活性、宰前活重、胴体重、屠宰率、眼肌面积以及羊肉粗蛋白含量均显著高于对照组(P<0.05)。随着补饲蛋白水平的增加,血清尿素氮含量呈线性增加(P<0.05),而羊肉水分含量呈线性减少(P<0.05);平均日增重、血清总胆固醇含量、血清葡萄糖含量和羊肉粗蛋白呈二次曲线变化(P<0.05)。结果表明:补饲不同蛋白水平日粮可以提高血清中血糖、尿素氮、总胆固醇浓度和谷草转氨酶活性,可以在一定程度上改善和提高北川白山羊的生产性能、屠宰性能及肉品质等,北川白山羊的补饲料适宜蛋白水平为16%。     

日粮能量水平对中卫山羊羯羊生长与屠宰性能的影响

选择出生和断奶时间相近、健康、平均体重差异不显著(P>0.05)的羯羔羊27只,随机分为3组。以不同能量水平日粮饲喂各组试验羊,并统计羯羊体重及增重变化情况。结果表明:3组试验羊的日粮在蛋白水平相同、能量水平不同的情况下日增重差异均不显著(P>0.05),但以第Ⅱ组试验羊平均日增重最高。     

谷氨酰胺在不同蛋白水平日粮下对断奶仔猪生产性能和血液指标的影响

试验研究了谷氨酰胺在不同蛋白水平日粮中对断奶仔猪的生产性能、腹泻率和血液指标的影响。试验选用120头28日龄的长×大二元杂交断奶仔猪,按体重、性别、窝别一致的原则随机分为6组,每组设2个重复,每个重复10头猪。第Ⅰ、Ⅲ、Ⅴ组为对照组,日粮蛋白水平分别为18%(低)、20%(中)、22%(高),第Ⅱ、Ⅳ、Ⅵ组在Ⅰ、Ⅲ、Ⅴ组基础上添加1.25%的谷氨酰胺(Gln),试验期为28 d。结果表明:高、中、低三种蛋白日粮中添加Gln与对照组相比分别可以提高断奶后0~2周日增重8.85%(P>0.05)、24.11%(P<0.05)、23.78%(P<0.05),全期来看,中蛋白组添加Gln与对照组相比可以有效提高日增重13.19%(P<0.05),降低料肉比3.73%(P>0.05);对腹泻率的影响,第Ⅱ、Ⅳ、Ⅵ组比对照组分别可以降低腹泻率35.12%(P<0.05)、60.47%(P<0.05)和60.76%(P<0.05),相互之间差异不显著(P>0.05);高蛋白、中蛋白和低蛋白的Gln组与对照组相比血清尿素氮的含量分别下降了23.32%(P<0.05)、34.52%(P<0.05)和37.79%(P<0.05),血清总蛋白含量分别提高了5.89%(P<0.05)、24.58%(P<0.05)和7.26%(P>0.05),白球比值分别下降了17.73%(P<0.05)、12.59%(P<0.05)和1.49%(P>0.05)。本试验条件下,在20%蛋白水平日粮中添加Gln对提高断奶后仔猪的日增重,降低腹泻率达到最优效果。     

不同能蛋水平日粮对安格斯公牛生长性能及血清生化指标的影响

试验研究高能蛋水平(Ⅰ组)、中能蛋水平(Ⅱ组)、低能蛋水平(Ⅲ组)日粮对安格斯公牛生长性能及血清生化指标的影响。选择10～12月龄、平均体重为(313.53±13.32) kg安格斯公牛30头,随机分为3组,每组10头。Ⅰ组、Ⅱ组、Ⅲ组试验牛分别饲喂能蛋比为0.55～0.60、0.58～0.63、0.61～0.65的日粮,试验期150 d。结果表明:Ⅰ组平均日增重最高(P>0.05),Ⅰ组耗料增重比显著低于Ⅱ组(P<0.05),Ⅰ组日增重效益高于Ⅱ组、Ⅲ组(P>0.05);Ⅰ组胸围增长量显著高于Ⅲ组(P<0.05);Ⅰ组血清中葡萄糖含量最高(P>0.05);Ⅰ组血清中总蛋白含量最高,其中试验前期Ⅰ组与Ⅲ组之间差异显著(P<0.05);Ⅰ组血清中尿素氮含量均显著高于其他两组(P<0.05)。说明提高日粮能蛋水平可以促进饲粮中营养物质的消化吸收,提高肉牛的日增重和育肥效益,改善血清中葡萄糖、总蛋白水平,并维持机体正常生理功能。综合各项指标,试验牛饲喂高能蛋水平日粮效果最优。     

不同蛋白水平日粮对中卫山羊育成母羊消化率影响的研究

舍饲条件下,选择11月龄、健康、平均体重相近的中卫山羊育成母羊21只,随机分为3组,分别饲喂不同蛋白水平的日粮。采用消化试验、比较饲养试验来测定其对不同蛋白水平日粮的消化率及增重的影响。结果表明：在本研究所采用的能量水平和蛋白梯度下,第Ⅲ组高蛋白水平日粮对试羊的增重效果最好,而DM、ADF和NDF对增重效果影响不明显（P〉0．05）;粗蛋白消化率随粗蛋白水平的升高而升高,而DM、ADF和NDF消化率均以第Ⅱ组最高。     

高蛋白水平日粮对湖羊生长性能、肉品质及血常规的影响

本试验旨在研究2种不同蛋白水平日粮对湖羊生长性能、肉品质及血常规的影响。选择健康的5月龄公湖羊20只，随机分为2组，每组10只；对照组湖羊初始体重为（27.23±1.87） kg，基础日粮的粗蛋白水平为8.63%；高蛋白组湖羊初始体重为（27.21±1.79） kg，设计日粮的粗蛋白水平为16.35%；预试期7 d、正试期57 d。结果表明：高蛋白组湖羊试验结束时末重、平均日增重均显著高于对照组（P<0.05），料重比显著低于对照组（P<0.05）;2组湖羊的净肉率、骨率和骨肉比差异不显著（P>0.05），高蛋白组湖羊的宰前活重、胴体重、屠宰率和净肉重均显著高于对照组（P<0.05）;2组湖羊的肉品质相关指标无差异，其血常规指标均处于正常范围。由此可见，饲喂高蛋白水平日粮能显著提高育肥期湖羊生长性能，且不影响湖羊的健康和肉品质。     

不同饲粮粗蛋白质水平下蝇蛆蛋白替代豆粕对蛋鸡生产性能、蛋清品质及血清蛋白质代谢指标的影响

本试验旨在研究不同饲粮粗蛋白质水平下蝇蛆蛋白替代豆粕对蛋鸡生产性能、蛋清品质及血清蛋白质代谢指标的影响。采用单因素试验设计,选取252只产蛋率、体重相近的健康33周龄罗曼白蛋鸡,随机分为3组,每组7个重复,每个重复12只鸡。各组分别饲喂标准回肠可消化氨基酸(SIDAA)平衡模式下配制的不同粗蛋白质水平(16.50%、14.85%、13.20%)的玉米-豆粕-蝇蛆蛋白饲粮,各组蝇蛆蛋白与豆粕提供等量的粗蛋白质。预试期2周,正试期12周。结果表明:1)与16.50%组相比,14.85%组的产蛋率、平均蛋重、产蛋量、平均日采食量和料蛋比均无显著差异(P>0.05);13.20%组的料蛋比显著增加(P<0.05),产蛋率、产蛋量、平均蛋重和平均日采食量均显著降低(P<0.05)。2)与16.50%组相比,14.85%组的平均蛋重、蛋清重、浓蛋白重、蛋白高度、哈氏单位和蛋清比例均无显著差异(P>0.05);13.20%组的平均蛋重、蛋清重、浓蛋白重和蛋白高度显著降低(P<0.05),而蛋清比例、哈氏单位无显著差异(P>0.05)。3)各组血清谷草转氨酶、谷丙转氨酶活性及总蛋白、白蛋白、尿酸含量无显著差异(P>0.05),且输卵管膨大部组织学形态正常。由此可见,在本试验条件下,使用蝇蛆蛋白替代豆粕并使饲粮粗蛋白质水平降低至14.85%时未对蛋鸡生产性能和蛋清品质产生不良影响,但饲粮粗蛋白质水平降低至13.20%时则会产生不利影响。     

Comparison of meat quality characteristics and fatty acid composition of finished goat kids from indigenous and dairy breeds

The aim of the study was to compare the certain carcass and meat quality traits and also fatty acid composition of goat kids from indigenous breeds (Gokceada and Hair Goat) and dairy breeds (Saanen and Maltese). A total 40 male kids from Saanen, Gokceada, Maltese and Hair Goat breeds were collected from commercial farms after weaning. Kids were finished for 56 days with grower concentrate and alfalfa hay in the sheepfold until slaughter. Higher mean values were found for Saanen kids in terms of slaughter weight, hot carcass weight and real dressing compared with Maltese, Hair Goat and Gokceada kids under the same intensive conditions. On the other hand, there were no significant differences between breeds in terms of instrumental meat quality traits, except meat colour. Meat from Gokceada and Hair Goat kids had higher lightness and Hue angle values than Saanen kids after 24 h of blooming. High meat redness values were observed for Saanen kids after 0 and 1 h of blooming. Panellist appreciated cooked meat from Saanen and Maltese kids in overall acceptability. If the fatty acid composition of meat was taken into consideration, kids from Saanen and Gokceada breeds displayed better values, because of the lower ?SFA percentage and higher desirable fatty acids (C18:0?+?ΣMUFA?+?ΣPUFA) percentage than Maltese and Hair Goat kids. Our results indicate that male kids for Saanen which is dairy breed could be assessable for quality goat meat production.     

不同产羔数西农萨能奶山羊胎盘性状的差异分析

为研究不同产羔数西农萨能山羊胎盘性状的差异,本实验共收集73只(单羔24只;双羔42只;三羔7只)正常分娩的西农萨能奶山羊母羊胎盘,分析比较不同产羔数的胎盘效率(初生窝重与胎盘质量之比)、子叶承载效率(初生窝重与子叶总面积之比)、子叶密度(子叶总数与胎盘质量之比)、子叶面积等性状和子叶组织学结构与母羊繁殖性能之间的关系。结果表明:随产羔数增加,西农萨能山羊胎盘质量呈极显著增加;多羔组胎盘子叶总数、子叶总面积和子叶承载效率显著高于单羔组;组织学结构分析发现,胎盘子叶滋养层细胞数量、毛细血管数量及密度也随着产羔数增加而增加。因此,胎盘质量、子叶总数和子叶总面积等性状可能是高繁殖力母羊的选择指标之一。     

影响西农萨能奶山羊产奶性状的非遗传因素分析

本试验旨在探究母羊出生年度、季节、胎次、泌乳阶段4个固定效应对西农萨能奶山羊产奶性状的影响。以西北农林科技大学萨能羊原种场2006-2018年的645只泌乳母羊为研究对象,每月采集乳样1次,采样日早、晚各采集1次,将两次乳样等比例混合后,采用乳成分分析仪测定乳脂率、乳蛋白率、乳糖率、总脂固形物、非脂固形物、密度、冰点和酸度共8个指标,结合羊场产奶量记录,采用固定效应模型,通过SAS 9.4软件进行表型的描述性统计分析,再采用GLM模型进行固定效应对产奶性状的影响分析。结果表明,西农萨能奶山羊平均300 d产奶量为507.67 kg,乳脂率为3.58%,乳蛋白率为3.20%,乳糖率为4.19%;总固形物含量为12.21%,非脂固形物含量为8.46%;出生年度、胎次对产奶量影响极显著（P<0.01）,出生季节对产奶量影响不显著（P>0.05）;泌乳阶段、出生年度对乳脂率等8个乳成分性状均有极显著影响（P<0.01）,胎次对除乳蛋白率和总固形物的其他6个乳成分指标均存在极显著影响（P<0.01）。综合以上试验结果,胎次及泌乳阶段是影响西农萨能奶山羊产奶性状的两种主要非遗传因素,第3、4胎母羊产奶性能最佳,泌乳早期的乳品质更优,揭示了对种群进行良种选育工作和羊饲养管理的重要性,也为后期进行奶山羊经济性状遗传评估和群体遗传改良提供理论基础。     

饲粮中添加富含二十二碳六烯酸海藻对奶山羊青年公羔生长性能、屠宰性能、肌肉品质以及脂肪酸组成的影响

本试验旨在研究饲粮中添加富含二十二碳六烯酸(DHA)海藻对奶山羊青年公羔生长性能、屠宰性能、肌肉品质以及脂肪酸组成的影响。选取16只同质性较好的6月龄[平均体重为(21.90±0.98)kg]奶山羊青年公羔,随机分为2组(每组4个重复,每个重复2只羔羊),分别饲喂基础饲粮(对照组)和在基础饲粮基础上添加3%富含DHA海藻(干物质基础)的试验饲粮(试验组)。饲喂12周后,从每组随机选择4只公羔(共8只公羔)进行屠宰试验,测定屠宰性能、肌肉品质以及肌肉与脂肪组织中脂肪酸组成。结果显示:与对照组相比,1)饲粮中添加富含DHA海藻对公羔的干物质采食量、平均日增重和饲料报酬无显著影响(P>0.05);2)饲粮中添加富含DHA海藻对公羔的屠宰性能和肌肉品质无显著影响(P<0.05);3)饲粮中添加富含DHA海藻可显著降低血清中低密度脂蛋白胆固醇含量(P<0.05),显著提高高密度脂蛋白胆固醇含量(P<0.05),但对血清总胆固醇和甘油三酯含量无显著影响(P>0.05);4)饲粮中添加富含DHA海藻可显著提高肌肉和脂肪组织中DHA和n-3多不饱和脂肪酸(PUFA)含量(P<0.05),显著降低肌肉组织中n-6∶n-3 PUFA比值(P<0.05)。由此得出,在饲粮中添加富含DHA海藻对奶山羊青年公羔的生长性能、屠宰性能和肌肉品质均无显著影响,但有改善血脂指标以及肌肉与脂肪组织脂肪酸组成的潜力。     

不同能量和蛋白水平日粮对西农萨能奶山羊泌乳性能的影响

为筛选西农萨能奶山羊泌乳期全价料最适能量和蛋白水平,选取体重(50.56±0.76)kg、胎次(2～3)、产奶量(2.12±0.10)kg/d相近和分娩日期与体况一致,并处于泌乳高峰期的健康西农萨能奶山羊36只,随机分为6组,每组6只。采用3×2因子随机区组试验设计6种日粮,NE水平为12.64、13.08和13.52MJ/d,CP水平为16.13%和17.82%。试验期84d,共分4个阶段,每阶段21d。结果表明:日粮NE和CP水平对奶山羊DMI和血液生化指标没有显著影响,但存在交互作用,NE 13.52MJ/d和CP16.13%处理组的DMI最高。随日粮NE和CP水平升高泌乳量增加,其中CP提高可显著增加泌乳量(P=0.041);而乳脂肪、乳蛋白、乳糖、干物质和非脂乳固体等乳成分指标则降低,其中CP提高可显著降低乳蛋白(P=0.013)和非脂乳固体(P=0.031);日粮NE和CP水平对奶山羊泌乳性能的影响存在交互作用,NE 13.52MJ/d和CP17.82%时泌乳量最高,而NE 13.08MJ/d和CP16.13%时乳品质最好。综合各项指标并考虑生产实际,得出西农萨能奶山羊泌乳期日粮适宜的NE和CP水平分别为13.08MJ/d和CP16.13%。     

西农萨能奶山羊SERPINA1基因克隆、生物信息学及组织表达分析

本研究旨在克隆西农萨能奶山羊SERPINA1基因的CDS区,采用生物软件和在线预测工具进行生物信息学分析,通过实时荧光定量PCR技术检测SERPINA1基因在西农萨能奶山羊各组织间mRNA的表达水平。根据GenBank中山羊SERPINA1基因CDS区序列（登录号：XM_018066209.1）,利用Primer Premier 5.0软件设计特异性引物,RT-PCR扩增目的基因,构建原核表达载体测序后对序列进行生物信息学分析;采集西农萨能奶山羊心脏、肝脏、脾脏、肺脏、乳腺、肾脏、肌肉、瘤胃和小肠组织,提取组织RNA,反转录为cDNA模板,设计特异性定量引物,进行实时荧光定量PCR,检测SERPINA1基因在不同组织中的表达差异。结果显示,西农萨能奶山羊SERPINA1基因CDS区全长1 326 bp,编码441个氨基酸;同源性比对分析显示,西农萨能奶山羊与山羊、绵羊、牛和小鼠SERPINA1基因核苷酸序列同源性分别为100%、98.6%、95.7%和71.6%,与山羊亲缘关系最近,其次是绵羊。SERPINA1蛋白分子质量为48.71 ku,等电点为5.71,为跨膜亲水蛋白;SERPINA1氨基酸序列分别有62个磷酸化位点,3个跨膜区结构。组织表达分析显示,SERPINA1基因在西农萨能奶山羊肝脏组织中显著高表达（P<0.05）,其次是乳腺组织,在肺脏组织中表达量最低。研究结果为进一步探究SERPINA1基因在奶山羊乳蛋白合成代谢中的作用提供理论依据。     

Net mineral requirements for growth of Saanen goat kids in early life are similar among genders

The current mineral requirements for growing goat kids are based on sheep and cattle studies without differentiating between the stages of development or gender. The aims of this study were to determine the net requirements for growth of Ca, P, Mg, Na and K of Saanen goat kids during the initial stages of growth and to analyse the effect of gender on the net requirements for growth of these macrominerals. Eighteen female, 19 intact male and 10 castrated male Saanen goat kids were studied. The kids were selected applying a completely randomized design and slaughtered when their body weight (BW) reached approximately 5, 10 and 15 kg to determine the mineral requirements for growth at these stages. The net mineral requirements for growth were similar among genders. The goat kids had slightly increased net requirements of Ca, P and Mg for growth with increasing BW from 5 to 15 kg. The net requirements for growth of Ca, P, Mg, Na and K ranged from 9.61 to 9.67 g/kg of BW gain, 7.14 to 7.56 g/kg of BW gain, 0.34 to 0.37 g/kg of BW gain, 1.26 to 1.13 g/kg of BW gain, 1.88 to 1.82 g/kg of BW gain as the animals grew from 5 to 15 kg respectively. In conclusion, when formulating diets for Saanen goat kids in early growth stage mineral levels do not need to adjusted based on gender.     

Energy and protein requirements for maintenance and growth of Boer crossbred kids

Meat production by goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine the energy and protein requirements for maintenance and growth of 34 (3/4) Boer x (1/4) Saanen crossbred, intact male kids (20.5 +/- 0.24 kg of initial BW). The baseline group was 7 randomly selected kids, averaging 21.2 +/- 0.36 kg of BW. An intermediate group consisted of 6 randomly selected kids, fed for ad libitum intake, that were slaughtered when they reached an average BW of 28.2 +/- 0.39 kg. The remaining kids (n = 21) were allocated randomly on d 0 to 3 levels of DMI (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 kid from each treatment, and kids were slaughtered when the ad libitum treatment kid reached 35 kg of BW. Individual body components (head plus feet, hide, internal organs plus blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Initial body composition was determined using equations developed from the composition of the baseline kids. The calculated daily maintenance requirement for NE was 77.3 +/- 1.05 kcal/kg(0.75) of empty BW (EBW) or 67.4 +/- 1.04 kcal/kg(0.75) of shrunk BW. The daily ME requirement for maintenance (118.1 kcal/kg(0.75) of EBW or 103.0 kcal/kg(0.75) of shrunk BW) was calculated by iteration, assuming that the heat produced was equal to the ME intake at maintenance. The partial efficiency of use of ME for NE below maintenance was 0.65. A value of 2.44 +/- 0.4 g of net protein/kg(0.75) of EBW for daily maintenance was determined. Net energy requirements for growth ranged from 2.55 to 3.0 Mcal/kg of EBW gain at 20 and 35 kg of BW, and net protein requirements for growth ranged from 178.8 to 185.2 g/kg of EBW gain. These results suggest that NE and net protein requirements for growing meat goats exceed the requirements previously published for dairy goats. Moreover, results from this study suggest that the N requirement for maintenance for growing goats is greater than the established recommendations.     

Effect of protein : energy ratio in milk replacers on growth performance of goat kids

Two separate experiments were carried out to establish the effects of the protein:energy ratio in milk replacers on growth performance, plasma lipid concentrations and fatty acid composition in adipose tissue of male goat kids. In the first experiment there were 211 3-day- old goat kids and in the second experiment there were 121 kids aged 3-7 days. The animals were fed ad libitum for a period of 4 weeks on milk replacers containing either 11.5 or 9.5 g crude protein/MJ metabolizable energy. In essence, protein was exchanged with fat on a weight basis. Milk concentrations were increased from 160 to 190 g/l in experiment 1, from 150 to 180 g/l in experiment 2. There were significant increases in body weight and feed intake when the milk replacer with high protein : energy ratio was fed. Group mean average daily weight gain was 168 and 203 g for the groups with low and high dietary protein:energy ratio in experiment 1; for experiment 2 the values were 139 and 160 g. Average dry matter intake was 18 and 14% higher for the diet with high protein:energy ratio in experiments 1 and 2, respectively. There was no change in either feed conversion (feed:gain ratio) or energy conversion (weight gain:energy intake ratio). There were no consistent diet effects on plasma lipid concentrations. Dietary fatty acid composition was reflected by that of adipose tissue. The milk replacer with high protein:energy ratio produced a small increase in the contents of myristic and palmitic acid in adipose tissue.     

PRLR基因外显子10多态性与西农萨能奶山羊产奶性能的相关分析

设计4对引物,采用PCR—SSCP技术检测催乳素受体（PRLR）基因外显子10在西农萨能奶山羊群上的单核苷酸多态性,同时研究该基因对其产奶性能的影响。结果表明：引物P2、P3与P4扩增片段具有多态性,P1的扩增片段不存在多态性。应用P2扩增片段,在西农萨能奶山羊中仅检测到AA和AB基因型,纯化测序表明AA与AB基因型相比有2处突变,C27T的突变没有导致氨基酸变化,第189处的碱基缺失导致氨基酸由组氨酸变为酪氨酸和苏氨酸。AA和AB基因型之间产奶量的最小二乘均值差异显著（P〈0．05）,AA基因型在各胎次产奶量和平均产奶量等指标上均高于AB基因型,其中第3胎的产奶量达到显著水平（P〈0．05）;应用R扩增片段,在西农萨能奶山羊中检测到3种基因型（CC、CD、DD）,纯化测序表明CC与DD基因型相比有2处突变（C103A和T106C）,分别导致氨基酸由赖氨酸变为苏氨酸、苏氨酸变为异亮氨酸;3种基因型之间产奶量的最小二乘均值差异不显著（P〉0．05）。应用P。扩增片段,在西农萨能奶山羊中也只检测到EE和EF基因型,纯化测序表明EE与EF基因型相比有1处突变（A114G）,该突变导致氨基酸由蛋氨酸变为缬氨酸;EE和EF基因型之间产奶量差异显著（P〈0．05）。EE基因型的个体各胎次产奶量均比EF型高,其中在第3、4胎产奶量和前4胎平均产奶量3项指标上都达到显著水平（P〈0．05）。研究结果提示：PRLR基因对奶山羊产奶量有显著影响,因此认为PRLR基因外显子10位点可作为奶山羊高产奶量的标记辅助选择的有效分子标记。