肉用绵羊二元杂交组合的筛选及CLPG基因遗传效应研究

为了筛选出适宜于河北省唐山地区养殖的肉用绵羊最佳杂交组合，更好地指导生产实践，本研究以小尾寒羊为母本，分别以澳洲白羊（AWF）、杜泊羊和夏洛莱羊为父本，分3组进行杂交试验，其中，1组为澳洲白羊和小尾寒羊杂交（AH组），2组为杜泊羊和小尾寒羊杂交（DH组），3组为夏洛莱羊和小尾寒羊杂交（XH组）。对3组肉羊杂交F1代羊的生长性能和CLPG基因的遗传效应进行测定和分析。结果表明，在相同饲养条件下，除夏寒F1代母羊的初生重略低于澳寒F1代母羊外，夏寒杂交F1代羊的初生重（公羊）、断奶重、6月龄体重、初生到断奶时的平均日增重均为最高，且显著或极显著的高于杜寒和澳寒F1代羊（P<0.05，P<0.01）。断奶到6月龄时的平均日增重，杜寒F1代公、母羊均为最高，其次是夏寒F1代公、母羊，杜寒F1代公、母羊与其余两组均未达显著性差异（P>0.05）。3月龄体尺指标除了体长和胸宽，6月龄体尺指标除了体长和体高，其余均是夏寒F1代羊最大，且部分指标极显著高于澳寒F1代羊（P<0.01）。以上研究结果说明，夏寒F1代羊，基础体重较高，出生后生长速度始终较快，而杜寒F1代羊在断奶后表现出较快的生长速度。3个肉羊杂交组合F1代羊CLPG基因的遗传效应分析结果表明，CLPG基因的第41 bp处存在一个错义突变位点（g.C > T），该位点有CC和CT 2种基因型，其中CC为优势基因型，C为优势等位基因。具CT型个体的初生重、断奶重、6月龄体重以及3月龄和6月龄各体尺指标，均明显高于具CC型的个体。综合以上结果，提示夏洛莱羊与小尾寒羊杂交优势较为明显，T等位基因可促进肉用绵羊的生长发育，建议在河北省唐山地区进行肉羊生产时，尽可能选择夏寒杂交组合且携带有T等位基因的个体。

Screening of Hybrid Combinations and Genetic Effects Analysis of CLPG Gene in Meat Sheep

In this study, in order to screen out the optimal meat sheep hybrid combination for suitable breeding in Tangshan area, Hebei Province, and to better guide production practices, three groups of meat sheep hybridization experiments were carried out, using AWF sheep, Dorper sheep and Charolais sheep as the male parent respectively, and the Small-tail Han sheep as the female parent. Among them, group 1 was the hybrid combination between AWF sheep and Small-tail Han sheep (AH group), group 2 was the hybrid combination between Dorper sheep and Small-tail Han sheep (DH group), and group 3 was the hybrid combination between Charolais sheep and Small-tail Han sheep (XH group). The growth performance and genetic effects of CLPG gene in hybrid progeny (F1) of 3 groups meat sheep were measured and analyzed. The results showed that under the same feeding conditions, birth weight of Xiahan ewes was slightly lower than that of Aohan ewes, the birth weight(ram), weaning weight, 6-month-old weight and average daily gain from birth to weaning of Xiahan hybrid progeny (F1) were the highest, and significantly or extremely significantly higher than those of the Duhan and Aoan hybrid progeny (F1) (P<0.05, P<0.01). The average daily gain from weaning to 6-month-old of Duhan hybrid progeny (F1 rams and ewes) were the highest, followed by Xiahan hybrid progeny (F1 rams and ewes), and the difference between Duhan hybrid progeny (F1 rams and ewes) and the other two groups was not significant(P>0.05). Except for body length and chest width at 3-month-old, and body length and body height at 6-month-old, the residual body size indexes of Xiahan hybrid progeny (F1) were the highest, and some of them were extremely significantly higher than those of Aohan hybrid progeny (F1) (P<0.01). The above results indicate that the Xiahan hybird progeny (F1) had a higher basic body weight and a faster growth rate after birth,while Duhan hybrid progeny (F1) showed a faster growth rate after weaning. The genetic effects analysis of CLPG gene showed that there was a missense mutation site at the 41 bp for 3 meat sheep hybrid progeny(F1) populations. There were CC and CT genotypes at this mutation site. The CC genotype was dominant genotype, and C allele was dominant allele. The least squares analysis of genotype and growth traits showed that birth weight, weaning weight, 6-month-old weight, 3-month-old body size indexes and 6-month-old body size indexes of individuals with CT genotype were significantly higher than those of individuals with CC genotypes. Based on the above results, it is suggested that the hybridization advantage between Charolais sheep and Small-tail Han sheep is obvious. T allele can promote the growth and development of meat sheep. It is recommended to choose the Xiahan hybrid combination and the individual carrying T allele when organizing meat sheep production in Tangshan area, Hebei Province.