Serum Esterase Polymorphisms and Their Associations with Prolificacy in Small Tail Han Sheep

[ Objective] The aim of this research was to provide a theoretical basis for the.breeding and identification of multiparous Small Tail Han sheep. [ Method] The polymorphisms of serum esterase （Es） locus in Small Tail Han sheep were detected by vertical discontinuous polyacrylamide gel electrophoresis （PAGE）. According to the statistical analysis of different genotypes and their litter size, the correlation between Es polymor- phisms and litter size was analyzed. [ Result] There were three genotypes in Es locus, and Es^＋- was the dominate genotype. The differences of ewe litter size in the 1 ,t parity among these three genotypes were nonsignificant （ P 〉 0.05）, As far as the 2^nd and 3rd parity was considered, the litter size of genotype Es＋＋ was significantly （P〈0.05） higher than that of Es-- and Es^＋- ; the average litter size of Es＋＋ was extremely significant （ P 〈 0.01 ） higher than that of Es - - and Es ＋ - while there was no significant difference （ P 〉 0.05） between the latter two. [ Conclusion] The Es lo- cus could be regarded as a genetic marker locus for early selection of high-yielding ewes and Es ＋＋ is the high-yielding genotype of Small Tail Han sheep.

Study on FSHR and LHR mRNA Levels of Different BMPRIB Genotypes of Small Tail Han Sheep During the Oestrum

The relationship between different BMPRIB genotypes of Small Tail Han sheep and FSHR and LHR mRNA levels during the oestrum was studied using semiquantitative PCR. The results indicated that FSHR mRNA extracted from the right ovary of BB （1.14±0.11） ewes showed higher levels compared with AA （0.44±0.11） and AB （0.36±0.08） ewes （P〈0.01）, and LHR mRNA extracted from the right ovary of BB （0.42±0.02） ewes showed significantly higher levels compared with AA （0.23±0.02） and AB （0.25±0.04） ewes （P〈0.01）; however, the mRNA extracted from the left ovary showed no significant difference in levels among the genotypes during the oestrum. It indicated that the fecundity induced by a mutation of BMPRIB in Small Tail Han sheep may be related to the changes of the mRNA expression of LHR and FSHR in ovary.

Polymorphism of BMPR-IB Gene and its Relationship with Litter Size in Small Tail Han Sheep

[ Objective] To open an exit for breeding high-fecundity Small Tail Han sheep according to genotypes. [ Method] By the PCR-RFLP, the polymorphism of ovine BMPR-IB gene was detected in Small Tail Han sheep of basic population and breeding population. And its relationship with litter size was analyzed. [ Result] In the basic population, the frequencies of B ＋ and BB genotypes were 77.78% and 14.81%, respectively, and their litter size per parity was 1.77 and 2.40, respectively. In the breeding population, the frequencies of B ＋ and BB genotypes were 51.79% and 40.18%, respectively, and their litter size per parity was 2.54 and 3.02, respectively. [ Conclusion] The ovine BMPR-IB gene can be used as a molecular Qenetic marker for fecundity traits to establish high-fecundity Small Tail Han sheep.

Relevance between BMPR-IB Genotypes and Litter Size in Small Tail Han Sheep

[ Objective] To detect the polymorphism of BMPR-IB gene and analyze the relevance between genotype frequency of FecB gene and litter size. [Method] Mutation sites in the BMPR-IB gene of Small Tail Hart sheep were analyzed by PCR-RFLP. [ Resluts] The percentages of individuals with BB, B ＋ and ＋ ＋ genotypes were 24.69%, 54.89% and 20.42%, respectively, and their average litter size per parity was 3.01,2.81 and 2.16, respectively. E Conclusion] The BMPR-IB gene can be used as a molecular genetic marker in fecundity traits. The FecB gene can effectively increase litter size of the Small Tail Han sheep and has additive action on litter size.

Comparison of Growth and Development Traits among Crossbreds of Dorset and Local Sheep Varieties in Gansu Province

In order to improve the meat production performance of local sheep varieties in Gansu Province, Dorset was introduced to crossbreed with the local sheep varieties, including Tan sheep, Small Tail Han sheep and Mongolia sheep. The offspring of different crossbreeding combinations were sampled randomly at different growth stages, and their growth and development traits were measured so as to screen out the best crossbreeding mode. The results showed that under the same crossbreeding mode, the growth rate of F3 was higher than that of F2, and of F2 was higher than that of F1. Among the F3 population, the growth rates of Dorset ×Han and Dorset × Mongolia hybrids were higher. Compared with those of Dorset ×Tan F3 hybrids, the body weights of male and female Dorset × Han and Dorset ×Mongolia F3 hybrids were increased by 5.59%, 4.40%, 5.93% and 3.76%, respectively. Among the F2 population, the growth rates of Dorset × Han and Dorset ×Mongolia hybrids were also higher. The body weights of male and female Dorset ×Han and Dorset × Mongolia F2 hybrids were higher than those of Dorset × Tan ×Han F2 hybrids by 5.99%, 3.67%, 9.80% and 5.00%, respectively. In the F1 population, the growth rates of Dorset × Han and Dorset × Mongolia hybrids were higher.Compared with those of Tan × Han F1 hybrids, the body weights of male and female Dorset × Han and Dorset × Mongolia F1 hybrids were increased by 11.32%,5.22%, 7.60% and 7.20%, respectively. Therefore, in the feeding area of Small Tai Han sheep, Mongolia sheep and Tan sheep, Dorset was the best sire for producing hybrid lambs. The economic benefit of crossbred offspring was obvious.

Construction of SMART cDNA Library of Sheep Ovary and Identification of Candidate Gene by Homologous Cloning

The cDNA library of an ovary from Small Tail Han sheep before estrus was constructed by switching mechanism at 5＇ end of RNA transcript （SMART） approach. This library had a plaque titer of 1 x 109 pfu mL-1 and a 96% recombinant ratio of which the fragment length of inserted average cDNA sequences was 1.0 kb. Based on bioinformatics analysis of the sequences, we obtained 338 expressed sequence tags （ESTs） from 380 cDNA clones which indicated 191 contigs. These contigs consist of 89 unmatched ESTs, 9 homologous known genes in sheep, and 93 homologous sequences in species of mouse, bovine, and human beings, including 19 sequences expressed in the ovary or follicle and 14 unknown sequences. Several candidate genes associated with sheep reproduction trait such as epidermal growth factor （EGF）, estrogen receptor （ESR）, Inhibin, follicle stimulating hormone receptor （FSHR）, prostaglandin （PG）, and transforming growth factor-β （TGF-β） were identified and the homologous were cloned from this library, which will contribute to compile expression profiles and find the major genes of prolificacy of Small Tail Han sheep.

Improving the Local Sheep in Gansu via Crossing with Introduced Sheep Breeds Dorset and Borderdale

In order to improve the meat performance of local sheep in Gansu Province,Dorset and Borderdale were introduced to crossbreed with local sheep which were Tan sheep,Small-tail Han sheep and Mongolia sheep. The offspring under different crossbreeding combinations were sampled randomly at the different growing stage to measure their growth traits so as to select optimize the crossbreeding mode. The results indicated that,for the same crossbreeding mode,the growth rate of progeny was in order F3】 F2】 F1; for the F3 progeny,the combinations Dorset- Borderdale- Small tail Han sheep and Dorset- Borderdale- Mongolia sheep gave a higher growth rate,with a body weight of 1. 57%,3. 17%,8. 23%,1. 15% higher in male and female individuals than the counterparts of Dorset and Tan sheep and Small tail Han sheep; for the F2 progeny,the combinations Dorset- Borderdale- Small tail Han sheep and Dorset- Borderdale- Mongolia sheep also gave a higher growth rate,with a body weight of 2. 15%,4. 53%,9. 21% and 2. 75% higher in male and female individuals than the counterparts of Dorset and Tan sheep and Small tail Han sheep; for the F1 progeny,the combination Borderdale and Small tail Han sheep assumed a higher growth rate,with a body weight of 3. 23%,6. 07%,7. 42% and 8. 66% higher in male and female individuals than the counterparts of Borderdale- Mongolia sheep and Tan sheep- Small tail Han sheep,respectively. Therefore,in the Small-tail Han sheep and Mongolia sheep producing regions,the F2 or F3progeny bred by using Dorset or Borderdale sheep as male parent to cross with local breeds,or the hybrid lambs of Small-tail Han sheep and Borderdale sheep as highly qualified commodity,would produce significant economic benefit. Moreover,the novel breeds obtained by crossing were the valuable genetic resource for breeding meat sheep.

小尾寒羊营养素和生态环境的相关性研究

近年随着强农惠农政策的实施,我国羊类养殖数量常年居于世界首位。小尾寒羊养殖条件简单、收益见效快,受到养羊生产者的广泛关注。吉林西部草原盛产羊草,是小尾寒羊育种生产基地。研究以西部草原生态区小尾寒羊为对象,采集心肝肾与肌肉运用凯氏定氮法、高温灼烧法等测定肉品中水分脂肪等含量,用SPSS 12.0统计软件对数据分析,表明小尾寒羊肉营养成分全面,肉品重金属检出值符合无公害畜禽肉安全要求,肉中蛋白质与重金属含量在不同草原类型间无显著性差异。