快慢羽品系贵妃鸡体尺性状及屠宰性能的比较分析

对20周龄的6只快羽贵妃鸡与6只慢羽贵妃鸡的体尺性状与屠宰性能进行比较分析.结果表明,两品系间的体尺性状与屠宰性能均为慢羽鸡大于快羽鸡,且髋宽、半净膛率两品系间差异显著(P<0.05).两品系间的内脏器官的体积大小和骨架结构大小存在一定的规律性,骨架指数与睾丸重慢羽鸡均大于快羽鸡,器官指数则是慢羽鸡小于快羽鸡.     

波尔山羊与睢宁白山羊杂交羔羊生长性能研究

研究波尔山羊与睢宁白山羊F1 代、F2 代的生长发育情况 ,结果从出生到 3个月不同日龄羔羊的体重体尺均高于纯种睢宁白山羊 ,杂交优势显著 ,F1 代体重的杂种优势率为 18 96 % ,杂种后代生长性能比睢宁白山羊好     

甘肃省杂优猪杂交父本的合成研究——杂交猪DA、DB、DC肉用性能的同期比较

在同一条件下研究比较杜洛克（Ｄ） 与Ａ、Ｂ、Ｃ３ 个新品系猪杂交后代的肉用性能。结果显示, ＤＡ、ＤＢ、ＤＣ 的生长速度分别为７５７－３２ 、７１８－８１ 、６８６－６７ ｇ／ｄ 。料重比依次为３－５８ 、３－５４、３－７０ 。屠宰测定, ＤＡ、ＤＢ 的胴体瘦肉率比ＤＣ分别高７－５１ ％ （ Ｐ＜ ０－０５） 和１３－３８ ％ （ Ｐ＜ ０－０１） ,脂肪率ＤＣ比ＤＡ、ＤＢ 分别高１４－８４ ％ （ Ｐ ＜ ０－０５） 和３１－１５％ （ Ｐ ＜ ０－０１） , ＤＡ 和ＤＢ 无显著性差异。其它胴体性状水平各组间无显著性差异。ＤＡ、ＤＣ 的肉质性能良好, ＤＢ 表现轻度的ＰＳＥ 肉     

Ostrich meat: Production,quality parameters,and nutritional comparison to other types of meats

The poultry industry is considered one of the most efficient industries in producing animal protein. Poultry production consists of several main segments: broilers, commercial eggs, turkeys, ducks, and other poultry, including geese, guinea-fowl, pheasants, quail, and ratites. Currently, ostrich meat is marketed as a healthy red meat because it is characterized by high polyunsaturated fatty acid contents, low saturated fatty acid content, and low cholesterol level compared with red meats, such as beef, while tasting similar to lean beef. Ostrich meat contains lower sodium and higher iron contents than other kinds of meat, making it preferable to hypertensive people and those with anemia. Taken together, ostrich meat is considered as an ideal red meat for individuals seeking healthier lifestyle. Moreover, many different ostrich products, such as leather and feathers, are used by people. The current review paper considers the quality characteristics of ostrich meat, including physical traits, and compares it to other types of meats, such as bovine and other poultry meats.     

柞蚕杂种优势的研究与利用

我国自20世纪70年代开始系统开展柞蚕杂种优势的研究,从柞蚕不同经济性状的杂种优势分析,到通过重要生化酶指标预测主要经济性状的杂种优势表现,为柞蚕优良新品种选育奠定了理论基础。依据对交亲本的亲缘关系、遗传特性、主要性状表现,采用二元、三元或多元杂交形式组配的柞蚕优良杂交组合,使生产上推广的柞蚕新品种较大程度地发挥了增产增收作用,生产上柞蚕杂交种的普及率已达到90%以上。今后应充分利用现代分子生物学技术手段,加强柞蚕重要经济性状的遗传规律研究及育种材料的创新,提高杂种优势的利用率;针对柞蚕杂交组合的特殊性,在生产上采用合理的放养利用模式,并严格按杂交形式繁育优势杂交组合的对交品种,保证生产用杂交种的品质。     

Fine mapping quantitative trait loci under selective phenotyping strategies based on linkage and linkage disequilibrium criteria

In fine mapping of a large‐scale experimental population where collection of phenotypes are very expensive, difficult to record or time‐demanding, selective phenotyping could be used to phenotype the most informative individuals. Linkage analyses based sampling criteria (LAC) and linkage disequilibrium‐based sampling criteria (LDC) for selecting individuals to phenotype are compared to random phenotyping in a quantitative trait loci (QTL) verification experiment using stochastic simulation. Several strategies based on LAC and LDC for selecting the most informative 30%, 40% or 50% of individuals for phenotyping to extract maximum power and precision in a QTL fine mapping experiment were developed and assessed. Linkage analyses for the mapping was performed for individuals sampled on LAC within families and combined linkage disequilibrium and linkage analyses was performed for individuals sampled across the whole population based on LDC. The results showed that selecting individuals with similar haplotypes to the paternal haplotypes (minimum recombination criterion) using LAC compared to random phenotyping gave at least the same power to detect a QTL but decreased the accuracy of the QTL position. However, in order to estimate unbiased QTL parameters based on LAC in a large half‐sib family, prior information on QTL position was required. The LDC improved the accuracy to estimate the QTL position but not significantly compared to random phenotyping with the same sample size. When applying LDC (all phenotyping levels), the estimated QTL effect were closer to the true value in comparison to LAC. The results showed that the LDC were better than the LAC to select individuals for phenotyping and contributed to detection of the QTL.     

黄羽肉鸡ACSL1基因多态性与腹脂性状的相关性研究

长链酯酰辅酶A合成酶(ACSLs)是长链脂肪酸通过硫代酯化进而合成酰基辅酶A衍生物所必需的酶,也是脂肪酸代谢的第一步.哺乳动物ACSL家族由ACSL1、ACSL3、ACSL4、ACSL5和ACSL65个不同的成员组成,ACSL1是主要的异构体之一.为探讨黄羽肉鸡ACSL1基因作为腹脂性状分子标记的可行性,本实验采用PC...     

鲤脑组织cDNA文库的构建及鉴定

用Gubler—Hoffman法构建了耐低温鲤Cyprinuscarpio脑组织全长cDNA文库,经测定库容量为5．7×10^5cfu／mL,文库的重组率接近95％,平均插入片段长度为1500bp,符合文库保存和筛选实验的要求。同时,根据鲤与低温相关的消减eDNA文库中低温下特异表达基因的片段序列,设计了PCR引物,并在此eDNA文库中进行PCR检测和序列测定。使用BLAST软件将测序的10个cDNA序列同GenBank等数据库进行比对,结果显示,8个阳性克隆有相关同源性,2个克隆为功能未知的基因,全长率接近75％。     

Power of a genome scan to detect and locate quantitative trait loci in cattle using dense single nucleotide polymorphisms

There is increasing use of dense single nucleotide polymorphisms (SNPs) for whole‐genome association studies (WGAS) in livestock to map and identify quantitative trait loci (QTL). These studies rely on linkage disequilibrium (LD) to detect an association between SNP genotypes and phenotypes. The power and precision of these WGAS are unknown, and will depend on the extent of LD in the experimental population. One complication for WGAS in livestock populations is that they typically consist of many paternal half‐sib families, and in some cases full‐sib families; unless this subtle population stratification is accounted for, many spurious associations may be reported. Our aim was to investigate the power, precision and false discovery rates of WGAS for QTL discovery, with a commercial SNP array, given existing patterns of LD in cattle. We also tested the efficiency of selective genotyping animals. A total of 365 cattle were genotyped for 9232 SNPs. We simulated a QTL effect as well as polygenic and environmental effects for all animals. One QTL was simulated on a randomly chosen SNP and accounted for 5%, 10% or 18% of the total variance. The power to detect a moderate‐sized additive QTL (5% of the phenotypic variance) with 365 animals genotyped was 37% (p < 0.001). Most importantly, if pedigree structure was not accounted for, the number of false positives significantly increased above those expected by chance alone. Selective genotyping also resulted in a significant increase in false positives, even when pedigree structure was accounted for.