An Study On Serum Protein Polymorphism Of Four Lean Meat Type Swine Breeds (Lines)

In this experiment, polymorphism of serum protein, including transferring(Tf), prealbumin(Pa), postalbumin(Po),amylase(Am),ceruloplasmin(Cp) and esterase (Es),of Large White, Landrace, Duroc and SD-III of Shanxi lean meat type swine was investigated by using vertical polyacrylamide gel electrophoresis (PAGE). From opinion of view of biochemical genetic polymorphism, each breed's hereditary variation and enzyme variation were analyzed. The correlation analysis between SD-III swine's reproductive performance and serum protein was also carried out. We can get certain bases providing for selecting parents used for crossbreeding. According to the differences of genetic distance, we can make better use of SD-III swine, and more correctly predict SD-III's heterosis(hybrid vigor). The results showed as follows: the six serum protein loci which are Es, Pa, Po, Tf, Am and Cp have polymorphism. These loci have 2, 2, 2, 3, 2, 2 alleles respectively. The allele frequencies of each locus reflect the genetic characters of different populations, and they also reflect character's difference among population. The number of effective alleles (Ne) in Large White, Landrace, Duroc and SD-III of Shanxi lean swine is 1.8608, 1.8497, 1.8870 and 2.1464, respectively. The polymorphism information content (PIC) is 0.3434, 0.4307, 0.3681 and 0.3527 separately. Herozygosity (H) is 0.4239, 0.4434, 0.4667 and 0.5273 respectively. The results of the fitness of Hardy-Weinberg equilibrium show that in different population Pa, Po, Tf and Am are in disequilibrium or extreme disequilibrium. According to the results of F-statistic and gene flow (Nm), the genetic differentiation between SD-III and Large White is biggest but the gene flow is the least. The experimental results indicated that between SD-III and Large White can carry out better hybridization with the purpose of improving quality of SD-III swine's carcass. The genetic distance showed that SD-III swine's genetic similarity is higher with Duroc's, so certain protein loci of SD-III swine are in disequilibrium. Through the statistic analyses between SD-III swine's reproduce performance (birth weight of litter, weaning weight of litter) and protein types, the genotype AB, BB of Tf is correlated with weaning litter weight significantly (P<0.05), so it can be used as the best selective index for SD-III swine's weaning weight. At the same time, we can infer that serum protein polymorphism is a practical method used for studying the degree of heredity and variance.