Study On The Effect Of CAST Gene Polymorphisms On Meat Traits In Pigs

Polymorphism of CAST gene were studied using RCR-RFLP in four swine breeds: Duroc(50 individuals), origin Rongchang pig(65 individuals), Neijiang pig(38 indivduals )and strain I of New Rongchang (72 individuals). The association between polymorphism of CAST gene and meat quality traits(tenderness, meat colour, water free lossing, lossed water drip ration Marbling and intramuscular fat (IMP)) was analysed. This study aims at providing effective genetic markers for MAS of meat quality and exploring the resources of China special swine breeds.The results were as follows:1 The genetic variation of three swine breeds(1) The CAST gene of three breeds (Duroc, origin Rongchang, Neijiang pig) were digested by Hinf I, Msp I, Rsa I. The results showed that there were polymorphisms in the breeds, and at this locus the populations were not at Hardy-weinberg disequilibrium.(2) The result showed: the dominant genotype of Duroc, Neijiang and Rongchang were ABCCEF, AACCEE, AACCEF, respectively.(3) There was a uncharacteristic bands about 120bp by digested using Hinfl in a Duroc which not found in the other pigs at all. The occurence of new digested site maybe attributed to the environment differences of introducing breeds.2 The association between polymorphisms of CAST gene of New Rongchang I and Meat quality traits.(l)The produced loci digested by one enzymes By F test, there were obvious difference in marbling values with the different genotypes digested by Hinf(p < 0.05).Thus, The produced loci digested by Hinf l. may be used as genetic markers of Marbling.there were obvious difference in IMP values with the different genotypes digested by Mspl (p < 0.05).Thus, The produced loci digested by Mspl may be used as genetic markers of IMP. We may select the individuals with the genotype of DD to IMProved average IMP values in the population. We may also select the individuals with the genotype of CC to make average IMP values in the population more reasonable.there were obvious difference in water free loss values with the different genotypes digested by Rsal (p < 0.05). We may cross the individuals with the genotype of EE and FF to Improved the ability of sustaining water of body in the population.(2) The produced loci digested by two enzymes there were obvious difference inIMP values with the different genotypes digested by Hinfl/'Mspl , Mspl/Rsal and Hinf l/Rsal(p< 0.05).Thus, The produced loci digested by two enzymes may be used as genetic markers ofIMP.there were obvious difference in tendeness values with the different genotypes digested by Hinfl/Rsal(P < 0.05).Thus, The produced loci digested by two enzymes may be used as genetic markers of tenderness.(3) The produced loci digested by three enzymes the genotype values digested by Hinfl I Msp I IRsa I had obvious difference ( P0.01 ) .The result showed that CAST gene related to tenderness and the dividuals with the genotype of ABCCFF should be eliminated.(4) In aconclusion,all kinds of meat quality traits with the genotype of AACCFF in strain I of New Rongchang pig are suit and accord with the dominat genotype of AACCFF in origin Rongchang pig.C4ST gene relate to meat quality traits and selecting CAST gene as MAS of meat quality traits is exact, strain I of New Rongchang pig must inher it at least 3/4 pedigree of Rongchang pig,which cannot sustain fine meat quality without it .