Studies on Effects CCKAR Gene and Its Association with Partial Economic Traits in Pigs
|School||Hunan Agricultural University|
|Course||Animal Genetic Breeding and Reproduction|
|Keywords||pigs CCKAR gene SNP growth traits meat-quality traits|
By adopting Polymerase Chain Reaction-Restrain Fragment Length Polymorphism（PCR-RFCP）,the genetic variations of +179A/G Hpy8I restriction enzyme digestion and +471C/G SatI restriction enzyme digestion of CCKAR gene were detected in 687 pigs including 9 groups:5 native breeds Ningxiang、Daweizi、Shaziling、Taoyuan.Wuzhishan.,and 3 foreign breeds Yorkshire,Landrace,Duroc,a hybrid breeds DLY（Duroc×Landrace×Yorkshire）.The differences of genotype frequencies between groups were analyzed by Chi Square Test.At the same time,the effects on growth traits and meat-quality traits of CCKAR gene.Results were obtained as follows:1 The +179A/G loci of pig CCKAR gene1.1（1）There were great polymorphisms in +179A/G Hpy8I restriction loci of CCKAR gene in all breeds,and genotype AA,AG、GG were found in all breeds except Ningxiang was not found AA genetype;（2） Allele G was the superiority allele in the 9 breeds and AA genetype was ralely.（3）Both native and foreign breeds,GG genotype was the superiority genotype,The frequencies of allele G in native breeds were higher than the foreign breeds;1.2 On the growth traits,（1）The days-get-100kg-weight of GG genotype was significant difference lower than that of AA genotype in Duroc、Yorkshire and Landrace（P＜0.05）,their effects were 5.79%、4.81%、4.72%respectively.（2） The Growth Index trait of GG genotype of Duroc and Yorkshire were significant higher than A.A genotype（P＜0.05）;（3）Otherwise,the individuals of GG genotype had thinner Alive Back Fat thickness than the individuala of AA（P＜0.05）;All of this indicated that the allele G of CCKAR gene +179A/G locus took on certain positive effects on growth trait.1.3 On the meat-quality traits,（1） In Duroc、Yorkshire and Landrace,The meat color grade and marbling grade were presented some regulations in different genotye,and the total trend was AA＞AG＞GG,it was showed that allele A could inhance the grade of meat color and marbling,but the effects were not remarkable （P＞0.05）;（2）Concerning the water loss traits of Yorkshire and DLY,the individuals of AA genotype were lower the individuals by 11.42%、12.84%respectively,the difference between AA genotype and GG genotype was remarkable（P＜0.05）;（3）On the trait of Drip loss,the individuals of GG genotype were higher than the AA genotype,their effects were 39.68%、27.87%、46.84%respectively（P＜0.05）,Selecting the AA genotype could reduce the Drip loss obviously;so it was likely that allele A was a favorable allele on the the meat-quality traits in pigs;2 The +471C/G loci of pig CCKAR gene2.1（1）There were great polymorphisms in +471C/G SatI restriction loci of CCKAR gene in all breeds,and genotype AA、AG、GG were found in all breeds,and the distributing of the individuals of GG genotype was numerous,GG genotype was the superiority genotype;（2）In this locus,there was no significant difference between local breeds and foreign breeds in genetic diversity;in foreign breeds and hyrid breeds, Allele G was the superiority allele,in the local breeds,Allele C was the superiority allele;（3）All breeds in this locus showed great polyphism（0.25＜PIC＜0.5） and great genetic variations;2.2 On the growth traits,（1）The days-get-100kg-weight and The Growth Index trait of GG genotype was significant superioritier than that of AA genotype in Duroc、Yorkshire and Landrace（P＜0.05）;（2）On the CABF trait,the individuals of GG genotype had a significant difference with the individuals of AA genotype in Yorkshire（P＜0.05）;（3）As a whole,in Duroc、Yorkshire and Landrace,the +471C/G locus of CCKAR gene GG genotype showed some superiority than AA genotype on these traits,including Age100、ABF、CABF and I.Allele G had the positive effects on growth traits in pigs,inhancing the freqrency of allele G could improve the pace of growth in pigs;2.3 On the meat-quality traits,（1） In Duroc and Yorkshire The meat color grade of CC genotype was higher than GG genotyoe,especially in Duroc,the individuals of CC genotyoe was higher than CC、CG genotype 16.12%、8.56%respectively,there were a signicant difference between CC and GG genotype in Duroc and Yorkshire （P＜0.05）,in Landrace and DLY,showed a nonsignificant trend in the same direction （P＞0.05）;（2）On marbling grade trait,foreign breeds showed the trend AA＞AG＞GG, especially in Yorkshire and Landrace,there were a signicant difference between CC and GG genotype（P＜0.05）;（3）On pH Value trait,the pH value of GG genotype was hiner than CC genotype,and the difference was siginificant（P＜0.05）;So,the association between the different,genotype,of CCKAR gene +471C/G locus and partial meat-quality traits in pigs indicated that +471C/G locus might be a molecular marker on meat color grade and marbling grade.The studies indicated that CCKAR gene could be used as a candidate gene or molecular marker related to partial growth traits and meat-quality traits in pigs,and provided a way of molecular breeding to produce pigs with fast growing and high quality meat.