| Recent years, Hu sheep have been massive introduction in Xinjiang and hybridization with local produce to births multiPe sheeps. Due to the feature of birth sevarel lambs, the ewe milk yield can’t suit the lambs lead to the lack of nutrition has become quite prominent issue, resulting of poor lamb growth and low resistance, result of the survival rate is reduced. The study start from the molecular genetic basis to study High fecundity gene of lactating Hu sheep, trying to find genetic markers to control the size of sheep milk production, to provide technical support for the modern breeding. We selectd 41 lactation Hu sheep in Eastern of Xinjiang for the study, milk yield and milk composition measured individuals. Aanalysis PRL and PRLR gene polymorphism and genetic variation by the method of PCR sequencing and bioinformatics analysis. And using the method of least squares to analyze the correlation SNP loci and Hu sheep milk traits, conclusions as follow:1. Hu sheep populations milk yield measured in eight days, the lowest in the 8 week:(0.462 ± 0.02) kg, the highest in the 3 week:(0.606 ± 0.05) kg. After correction, the postpartum lactation total of about 56 days(31.25 ± 0.06) kg, average daily milk yield was(0.558 ± 0.05) kg, the milk yield increased rapidly in the first 1-10 days, The lactation reaches the highest in the 23 day. Hu sheep 1-56 days postpartum individual lactation milk yield was the lowest(14.34 ± 0.052) kg, the highest milk was(54.10 ± 0.078) kg. Research Wood lactation curve equation Y = Axbe-ct, 1-56 days for feeding sheep Lake lactation curve was simulated results Hu sheep shed 1-56 days postpartum lactation curve equation: Y = 450.30t0.264e-0.011 t. Available for 56 days postpartum lactation 48.72 kg, larger than the actual measurement results. The sheep with single lamb and sheep twins was negatively correlated of 1-56 day average milk yield, and the sheep with three lambs Hu sheep were positively correlated; produce twins and three lambs Hu sheep milk production was positively correlated. Early changes in milk composition is more obvious, which increases the number of days of lactation, lactose and total solids content of the rise; cream slowly rising early, slow decline after reaching a peak; protein content increased slowly in the late.2. 23 SNP loci have found in the PRL gene of Hu sheep. we only analysis the five sites which samPe size meet the statistical requirements and lactation traits correlation analysis. The results show: there are four growth traits associated with the SNP sites in Hu sheep, and in the SNP loci statistically significant. The animals carrying TT genotype at position 4591 showed a significantly higher milk yield than those with the GG genotype(P <0.05) in the eighth week; AC genotype was registered milk fat was significantly higher than CC genotype at position 1228(P <0.01) and in the animals carrying AC genotype mid-total solid at position 1228 is significantly higher than CC genotype(P <0.05); Moreover, the animals carrying AA genotype at position 1039 had a greater pre-fat percentage those AC and CC genotype(P <0.05); Ewes with AA and GG genotype showed a higher mid-fat percentage than the AG genotype at position 2351(P <0.05) while ewes carrying AA genotype showed a higher mid-protein ratio than AG and GG genotype,while the AA and AG genotype was significantly higher GG genotype(P <0.01); the animals carrying TT genotype at position 4244 showed a significantly higher early-fat percentage than those of CC genotype(P <0.01) while ewes with TT genotype showed a higher late-protein percentage and mid-total solids than CC genotype and(P <0.01). A total of 15 haPotypes were detected but the ewes samPes can’t suit the analysis require.3. Find a SNP site on the PRLR gene of Hu sheep, the locus AA, AT and TT genotype frequencies were 0.146(6), 0.439(18) and 0.415(17), χ2 fit testing the site in Hardy-Weinberg equilibrium. 1-5 weeks of lactation individual genotype differences were not significant(P> 0.05), 6-8 weeks of lactation ewes with A allele was significantly better than the T allele individuals individuals(P <0.05). The animals carrying AA and TA type of milk production from the beginning of the fourth week is larger than the TT genotype. Milkfat three genotypes among individuals, milk protein percentage, lactose rate, total solids was no significant difference(P> 0.05). But we can see different periods milkfat T allele than A allele; protein at different times higher than the rate of TA type TT and AA; genotype had no effect on lactose changes; total solids at different times higher than TA TT genotype and AA type. |
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