蛋鸡饲料利用率及其相关性状遗传参数的估计

用约束最大似然法(REML)估计纯种与杂种蛋鸡饲料利用率及其相关性状的遗传参数,材料源于一个正反反复选择(RRS)品种洛岛红和浅花苏赛克斯的饲料利用率的选择试验。6个世代有8388只试验鸡。各遗传组合在选择标准饲料利用率及其相关性状上存在着显著性差异,且杂种优于纯种。饲料利用率、产蛋率和产蛋量的遗传力为0.1～0.3,饲料消耗量为0.4,蛋重和体重为0.4～0.8。用母鸡组分估计的遗传力大于用公鸡组分估计出的。纯种与杂种在性状饲料利用率、蛋重、体重和产蛋量上表现为强正遗传相关(>0.7),在产蛋率和饲料消耗量上为中正遗传相关(0.4左右)。     

生长抑素和皮质抑素双表达DNA疫苗免疫杂交水牛育成牛的促生长效果研究

试验旨在探究生长抑素（SS）和皮质抑素（CST）双表达DNA疫苗免疫杂交水牛育成牛的促生长效果,并对其安全性进行验证。将鉴定正确的pVGS/2SS-2A-S/CST-asd质粒电转入减毒猪霍乱沙门氏菌C500构建生长抑素和皮质抑素双表达活载体疫苗。将16头6~12月龄杂交水牛育成牛随机分为低（TL）、中（TM）、高（TH）剂量组及PBS对照组（NC）,每组4头,试验组和对照组分别用双表达疫苗和PBS进行鼻腔免疫,初免时每天09：00和15：00免疫2次,连续免疫3 d,2周后以相同程序加强免疫1次,对免疫后不同时期的增重效果和免疫应答水平等进行监测。免疫应答结果显示,各剂量组免疫后均引起了免疫应答,TL组在初免后2周产生的SS抗体水平高于TM和TH组,而TM组SS抗体阳性率最高,为100%,优于TL （75%）和TH组（50%）;初免后2周产生的CST抗体水平则呈现完全相反的趋势,抗体水平随免疫剂量下降呈下降的趋势;初免后7周SS抗体和CST抗体水平和阳性率整体呈下降趋势,但也有部分牛出现抗体升高趋势;免疫因子检测结果显示,初免后2周TL和TM组IL-4水平极显著高于对照组（P<0.01）,而免疫后7周对照组的IL-4水平显著高于TL组（P<0.05）,与其他各组之间差异均不显著（P>0.05）;对照组INF-γ水平在初免后2周显著高于TL和TM组（P<0.05）,免疫后7周对照组显著高于TL组（P<0.05）,与其他各组之间差异均不显著（P>0.05）;对比抗体阳性组和阴性组发现,初免后2周抗体阳性组的IL-4水平极显著高于阴性组（P<0.01）,初免后7周则显著低于对照组（P<0.05）,而抗体阳性组INF-γ在初免后2和7周均显著低于阴性组（P<0.05）。增重效果检测显示,初免后2周各试验组平均日增重均显著高于对照组（P<0.05）,而在其他各时期各组之间差异均不显著（P>0.05）,抗体阳性组仅在初免后2周显著高于阴性组（P<0.05）。激素检测结果显示,各试验组生长激素（GH）和胰岛素样生长因子-1（IGF-1）在初免后2周均极显著高于对照组（P<0.01）,而初免后7周TL组GH和IGF-1水平显著低于对照组（P<0.05）,其他各组之间均差异不显著（P>0.05）;抗体阳性组的GH和IGF-1水平在初免后2周极显著高于阴性组（P<0.01）,而初免后7周则极显著低于阴性组（P<0.01）。安全性检测结果显示,各时期采集的水样、土样、粪样中均未检测到目的片段,证实了疫苗的安全性。本试验结果表明,双表达疫苗免疫后机体能产生良好的免疫应答,能提高育成牛的平均日增重,且对环境未产生安全性问题。     

Development of a RAPD marker-based classification criterion for quality semen production in Holstein crossbred bulls

In cattle production systems, an intense selection pressure for production traits has resulted in the decline of fertility traits. To optimize an efficient reproduction system, the inclusion of both male and female fertility traits in the selection process is very much essential. RAPD (Random Amplified Polymorphic DNA) was developed as a molecular biology tool and has been extensively used, to study intra- and interspecific genetic diversity. The present study was undertaken to utilize RAPD primers to investigate the association between DNA markers and semen quality traits viz. Sperm concentration, total sperm count ejaculate and initial sperm motility and thereby to identify good/poor semen producers. DNA isolated from the blood samples of healthy bulls was subjected to RAPD-PCR. The multiple regression analysis followed by independent t test was carried out to identify suitable markers. Based on the results, only 12 bands were identified as marker suitable for any of the quality trait. This includes, OPA2 ~ 760, OPA2 ~ 700, OPA6 ~ 1,200, OPA9 ~ 400, OPA9 ~ 380, OPA12 ~ 970, OPA14 ~ 715, OPA14 ~ 605, OPA16 ~ 485, OPA17 ~ 860 and OPA18 ~ 480. Multiple regression analysis selected, OPA2 ~ 760 and OPA2 ~ 1,750 for sperm concentration and OPA2 ~ 760, OPA2 ~ 700, OPA9 ~ 620, OPA4 ~ 670 and OPA18 ~ 1,015 for total sperm count/ejaculate. But the t test revealed a significant association between OPA2 ~ 760 and total sperm count. Further, discriminant function analysis also identified this marker in the first step itself. The results of the present study can be exploited as a low-cost alternative strategy for identification of good /poor semen producers in crossbred bulls at an early age.     

Effects of mycoplasmal pneumonia of swine (MPS) lung lesion‐selected Landrace pigs on MPS resistance and immune competence in three‐way crossbred pigs

To clarify the genetic influence of mycoplasmal pneumonia of swine (MPS) lesion‐selected Landrace (La) on MPS resistance and immune characteristics in three‐way crossbred pigs (LaWaDa), the LaWaDa pigs were compared with the non‐selected crossbred (LbWbDb) and purebred (La) pigs. The MPS lesion score in the three lines was as follows: La line < LaWaDa line < LbWbDb line, with significant differences among the lines. The proportions of myeloid cells and T cells were lower and higher, respectively, in the LaWaDa pigs compared with those in the other two lines. Messenger RNA (mRNA) expression of interleukin (IL)‐6, IL‐10, transforming growth factor‐β, and interferon‐γ in peripheral blood was significantly increased after vaccination in the La and LaWaDa lines. IL‐4 mRNA expression in the LaWaDa line was intermediate to the La and LbWbDb lines. Furthermore, principal component analysis for immune traits and MPS lesions was executed to clarify the characteristics of each pig line. These findings suggest that the immune responses in the three pig lines are genetically distinct and that MPS resistance and some immunity characteristics from the La line were transmitted to the three‐way crossbred pigs.     

FecB基因对杜×寒杂交肉羊产羔数及羔羊生长发育的影响

利用绵羊多胎基因FecB分子检测技术,检测分析杜×寒杂交肉羊基因型及对产羔数和羔羊生长发育的影响。结果表明：在杜×寒杂交F1、F2和F3代类群中,存在BB、B＋和＋＋三种基因型,并以B＋基因型为主。杜×寒F1代母羊B＋基因型频率极显著高于杜×寒F2、F3代母羊（P〈0.01）,F2代母羊B＋基因型频率显著高于F3代母羊（P〈0.05）。杜×寒F1、F2、F3代B＋基因型繁殖母羊产羔数比同代＋＋基因型母羊分别增加0.54、0.65和0.66只（P〈0.01）。杜×寒F1代繁殖母羊平均产羔数（1.67只）显著高于杜×寒F3代（P〈0.05）,比F2代平均产羔数增加0.28只（P〉0.05）。B＋基因型母羔初生体重、体尺和3月龄断奶体重极显著小于＋＋基因型母羔（P〈0.01）,B＋基因型公羔初生及3月龄断奶体重、体尺都小于＋＋基因型公羔（P〉0.05）,表明FecB基因不仅是影响杜×寒杂交肉羊产羔数的主效基因,而且在一定时期内也影响羔羊的生长发育。     

青贮饲料对波麻杂交羊血清指标和背最长肌脂肪酸组成的影响

为研究青贮饲料对波麻杂交羊血清指标及背最长肌脂肪酸组成的影响.选用体重为(35.3±1.5)kg的10月龄健康波麻杂交羊48只,公母各半,随机分为4组,Ⅰ组为对照组,未添加青贮饲料,Ⅱ、Ⅲ和Ⅳ组为试验组,分别添加非全株青贮玉米、全株青贮玉米、桑枝+全株玉米混合青贮饲料,试验期67d.结果 表明:(1)试验Ⅲ和Ⅳ组血清总...     

不同年龄阶段西杂肉牛育肥试验

对0.5岁(6头)、1岁(14头)、1.5岁(6头)西杂肉牛进行90d全舍饲育肥试验,结果表明:各组头均日增重分别为1.02kg、1.12kg、1.27kg。1.5岁组育肥增重效果最好(P<0.05)。     

皮埃蒙特、利木赞牛三元杂交组合幼牛产肉性能研究

本文对皮埃蒙特公牛×西黄杂种母牛 (西门塔尔公牛×当地黄牛 ,下简称皮西黄 )、利木赞公牛×西黄杂种母牛 (下简称利西黄 )两组合的三元杂交种幼牛肉用性能进行了研究。结果表明 ,两个组合肉性良好。 9月龄体重分别达 2 88.4kg和 2 5 9kg;育肥期平均日增重达 879.4g和 846.1 g。皮西黄屠宰率、净肉率、胴体产肉率和熟肉率分别为 5 8.2 5 %、47.5 0 %、81 .94%和 65 .4% ,利西黄分别为 5 5 .33%、45 .67%、82 .0 9%和 67%。皮西黄肉骨比、肉脂比、胴体优质切块比例和眼肌面积分别为4.5 5、1 0 .86、35 .1 2 %和 73.70 cm2 ;利西黄分别为 4.61、1 0 .2 3、33.38%和 63.1 0 cm2 。皮西黄产肉性能强于利西黄。     

肉牛2号对放牧条件下西杂牛的增重效果

本文研究了放牧条件下使用肉牛生长促进剂的效果，通过为期６０天的试验，喂添加剂组和不喂添加剂组的增重分别为２５ｋｇ、１７．８ｋｇ，试验组平均比对照组提高７．２ｋｇ（Ｐ〈０．０１）。试验还表明：在低日粮水平下，添加该加剂具有显著的增重效果，试验组头均收益较对照组高３６元，投入产出比为１：３，经济效益十分显著，具有推广应用价值。     

微贮秸秆和未经处理秸秆育肥肉牛对比试验

本试验利用经秸秆发酵活干菌处理的农作物秸秆和未经处理的秸秆对１６头１２月龄西杂黄牛进行育肥对比试验。结果表明：试验组牛的日增重比对照组牛日增重多０．２４４ｋｇ，提高２７．９％，差异显著（Ｐ〈０．０５）。