Study On The Relationships Between Polymorphisms Of Chicken Growth Hormone Gene And Slaughter And Meat Quality Traits

The polymorphisms of chicken growth hormone (GH) gene were detected by PCR-RFLP method with three different pairs of primers among 240 chickens from 8 populations (including 5 pure lines and 3 crossbreds developed by Sichuan Animal Science Academy and Dahen Poultry Breeding Company). Based on the detection of polymorphisms, the effects of different genotypes on slaughter and meat quality traits were analyzed.There was no polymorphism on Hin6I locus in the 5'regulatory region of GH gene. Three Msp I restriction enzyme sites with three alleles in the first intron (H1, H2 and H3) were observed. H1 was the dominant allele in each strain, and its frequency was significantly higher than that of H2 and H3. There were EcoRV and Ava I restriction enzyme sites with polymorphisms in the third intron, respectively. After the digestion with EcoRV enzyme, DNA segments showed two alleles and three genotypes. N was the dominant allele, and its frequency was notably higher than that of Mallele. There were two Ava I restriction enzyme sites with polymorphisms: locus A (240bp) and locus B (347bp). In locus A, the frequency of A2 allele was higher than that of A1 allele; while in locus B, the frequency of B1 was higher than that of B2 (except for the line S10) .The results by LSM (least square means) analysis and significant test showed that the abdominal fat weight (AW), abdominal fat percentage (AP) and the IMP content of A2A2 genotype had significant difference with those of A1A1 and A1A2 genotypes (P < 0.05), and had very markedly difference with A1A1 and A1A2 genotypes in subcutaneous fat thickness (SFT)(P < 0.01). In locus A of GH gene with Msp I, allele A1 could lower abdominal fat weight, abdominal fat percentage and subcutaneous fat thickness, but increase the IMP content. The genotypes of EcoRW had very significant effect on live body weight (BW)(P < 0.01). No differences were found for other traits. Two Ava I restriction enzyme sites were newly found in the third intron. In locus A, the abdominal fat percentage of A1A1 and A1A2 showed notable difference with that of A2A2 genotype (P < 0.05), and allele A2 could increase live body weight (BW), carcass weight (CW), eviscerated yield percentage (EP), semi-eviscerated yield percentage (SEP), breast muscle weight (BMW), breast muscle percentage (BMP), leg muscle weight (LMW) and leg muscle percentage (LMP), but reduce abdominal fat weight and its percentage and subcutaneous fat thickness. In locus B, abdominal fat weight and its percentage of B1B2 and B2B2 showed significant...