Study On Pig Immune Parameters And Their Relationship With Some Production Traits

In this study, two breeds (Large White and Zhongxu Black pig) were used. 4 immune traits, and 5 production traits were measured for 312 Large White and 209 Zhongxu Black pigs, including whole IgG titer(WIgG), specific antibody after vaccination to Hog Cholera Virus(HCVIgG), the functional activity of lymphocyte(FAL), phagocytic capacity of polymorphonuclear leukocytes(PA),birth weight(BW),weaning weight(WW), backfat thickness(BFT140) and loin eye area (LEA140), weight (W140)at 140 days. WIgG was measured by a double antibody sandwich-ELISA technique. HCVIgG was measured by an indirect ELISA technique. FAL was assessed by phytohemagglutinin(PHA) induced lymphocyte proliferation. PA was determined by a NBT enhanced showing color. The production traits were measured by the breeder in the farm.The results showed that the means of each immune trait obtained from Zhongxu Black pigs were higher than those of the corresponding traits from the Large White, but the means of each production trait obtained from Large White were better than those of the corresponding traits from the Zhongxu Black pig. When tested for significance, the mean values of FAL, PA, WW, BFT140 and LEA140 between two breeds were highly significant(P<0.01), but WIgG and WHO was significant(P<0.05). However, the mean values of HCVIgG, BW between Large White and Zhongxu Black pig were not significant (P>0.05 ) .The phenotypic correlating values between the humoral immunity traits and cellular immunity traits are low (0.172-0.224). The phenotypic correlating values in humoral immunity traits, cellular immunity traits are medium(0.310~0.563). But between immunity and production traits, the phenotypic correlations are relatively lower ( ~0.02~0.225 ) ,except the phenotypic correlations(0.259~0.333) of the FAL with BFTi4o,LEAi4o, and Wi4o.From the results of regression analysis, we can see that immunity traits are contributed largely to production traits. Many regression parameter are significant (P<0.05 ) . The heritabilities(h2)ofWIgG, HCVIgG, FAL, PA, BW, WW, W140. BFT140, LEA140 was 0.159, 0.102, 0.307. 0.422, 0.148, 0.095, 0.216, 0.257, 0.341,respectively,in Large White pigs. The genetic correlating values of all measured traits are close to the phenotypic correlating values, except the genetic correlating values of WW with WIgG, HCVIgG and FAL. The h2 of these measured traits in Zhongxu Black pigs are similar with that of the h2 in Large White pigs, but a litter high than that of the h2 in Large White pigs.In conclusion, this study has demonstrated variation in the immune status between two breeds, implying of a possible variation in then: immunological differences and disease resistance, Zhongxu Black pig is better than Large White, in these respects. Further more, the h2 of immune traits are medium. The correlations between iminune traits and production traits are low. So if we want to improve these two traits at the same time, it need further study involving more specific immune traits, greater pig numbers and new methods to allow evaluation of genetic characteristics.