Study On Polymorphisms Of PRL And GH Genes On GaoYou Duck And The Associations Between The Polymorphisms Of The Two Genes And Productive Traits

In this study, the PRL and GH genes were detected in Gaoyou Duck by PCR-RFLP and PCR-SSCP, respectively. The associations between polymorphism of GH and productive traits were analyzed.The genetic distribution of the polymorphisms of intronⅠof PRL gene in 5 different duck breeds including Gaoyou, Chaohu, Huainan, Jingjiang, Mianyang duck was tested by PCR-RFLPs in this study. The result indicated that the polymorphisms of that site were abundant in the 5 different duck breeds. There were three genotypes (AA,AB,BB) in all the breeds except for Huainan duck (AB,BB) ; Frequencies of allele A are 0.2857, 0.2879, 0.2286, 0.1667, 0.2833 in the 5 duck breeds respectively. B allele is the dominant allele in 5 duck breeds. Frequencies of genotypes in all breeds are in equilibrium of Hardy-Weinberg (P>0.05). A T/C mutation at the position of the 1,326 bp of the PRL gene in Gaoyou Duck was found by DNA sequencing. The least square analysis showed that the BB ducks had significant egg weight at the age of 30 weeks than AB ducks'(P<0.01), the double-yolk percentage of the AB ducks was much higher than that of BB ducks'(P<0.05) in double-yolk ducks, but there was not significant difference in egg number, longest clutch days and the body weight at first egg among 3 genotypes.42 Gaoyou Ducks at the age of 200 days are used to measured the correlations between contents of TP, contents of ALB, activity of AST, activity of ALT, activity of ALP, activity of LDH, activity ofα-AMY, contents of CHO, contents of HDL-C, contents of LDL-C, contents of P and the four productive traits(the eggs of 102 days, longest clutch days, the weight at first egg and egg weight at the age of 30 weeks) .The polymorphism of GH gene in Gaoyou Duck was analyzed by PCR-SSCP and relationships between GH genotypes and blood biochemical parameters and production traits were preliminarily analyzed. The results showed that: (1) Only AST in 11 blood biochemical parameters had a significant negative correlation with the weight at first egg. (P<0.01), the other four enzymes had a slight correlations with the eggs of 102 days, longest clutch days, the weight at first egg and egg weight at the age 30 of weeks. (2) Six pairs of primers for GH gene were designed according to the database of duck GH sequence. PCR-SSCP method was developed to screen the population. The mutations 3,701 T→C (GH extron 4) was observed by DNA sequencing. Three genotypes AA, AB and BB were found with the preponderant gene B frequency of 0.778 and the gene A frequency of 0.222. (3) The least square analysis showed that BB genotype ducks had significant higher (P<0.05) contents of LDL-C than AB genotype ducks. Individuals with different genotypes had no significant difference in other parameters, such as TP, ALB, AST, ALT, HDL-C, ALP, LDH, MY, CHO and P. The significant association between polymorphism of GH and highest clutch days was found (P<0.05). The highly significant associations between polymorphism of GH and weight of leg muscle and percentage of leg muscle were found (P<0.01). The liver weight of the AA ducks are much higher than BB ducks'(P<0.05).