Polymorphisms Of Gh, GHR And MSTN And Their Relationships With Meat Production Traits In Domestic Rabbits

GH, GHR and MSTN are very important genes controlling meat production traits in animals. The present study performed SNPs analysis in rabbit GH, GHR and MSTN genes, in nine purelines and 37 crossbreds of rabbit was analyzed by sequencing and PCR-SSCP, examined their polymorphisms in different rabbit populations and estimated their effects on meat production traits. The objective of this study is to find genetic diversity of rabbits at the molecular lever and useful DNA markers for meat production traits, and the reasonable protection of our rabbit lines to provide reliable and scientific basis for the use.The total sequence of rabbit GH gene was amplified and sequenced. No mutations were identified in the five exons and four introns comparing the sequences obtained in the analyzed rabbits. Only a single nucleotide polymorphism (SNPs) in 5'untranslated regions was identified. The genetic effect of this polymorphism on growth traits, partial carcass traits and meat production traits were investigated by GLM. The mutant allele had significant effect on carcass weight, loin weight, ham weight, fur weight, water holding capacity, cooked rate, intramuscular dry matter content and protein content (P<0.05). Mutant in which the individual carcass weight was significantly higher than wild-type and heterozygous individuals (P<0.05), but loin weight was significantly lower than the two (P<0.05). In the trait of ham weight, the heterozygous genotype was significantly lower than the wild type and mutant (P<0.05).For GHR gene, two mutations were found in exon 10, respectively, 1797 (T/C) and 2067 (C/T). On 1797 (T/C) locus, the connection analysis between genotypes and meat production traits showed that differences between different genotypes was not significant (P < 0.05). On 2067 (C/T) mutation, body weight at 35 days, body weight at 70 days, carcass weight, liver weight, forelegs weight, loin weight, ham weight, skin weight, intramuscular dry matter content and protein content of MN genotype were significantly better than NN and MM genotype (P < 0.05).This study investigated the MSTN gene in all three exons and partial 5'untranslated regions, and one single nucleotide polymorphism (T476C) in 5'untranslated regions was identified. Through analyzes the influence between the MSTN gene different genotype and slaughter and meat quality traits, finally indicated that this variation to muscle's cooked rate, water drop loss and the partial slaughter character has the remarkable influence. The mutant allele had significant positive effects on live weight, carcass weight, loin weight, ham weight, fur weight and muscle drip loss, and reduced cooked rate (P < 0.05). The results suggested that the variation in the upstream regulatory region of MSTN gene was beneficial to the body development.In domestic rabbit GH, GHR and in the MSTN gene, this research found 4 single nucleotide polymorphism markers, and has analyzed their performance and the relationship among different domestic rabbits, finally indicated that these three genes are likely to the major gene affecting the rabbits muscle development and growth, or have linkage with the main effect gene. And, the mutations in the GH gene, the MSTN gene 5'untranslated regions and the GHR gene 2067(C/T) can be developed as molecular markers for use at domestic rabbit breeding. These could provide the molecular basis for the heredity improvement of domestic rabbit meat quality, the enhancement of production performance and the high output strains or multiplication strains .