Preparation And Study Of CuZnSOD Gene Transgenic Pig

In recent years, high growth rate, low feed conversion and high lean percentage has been continuously improved. With the development of modern scale and intensive husbandry, oxidative stress in commercial pigs often occur, which caused serious damage to health, growth and meat quality of pigs. Copper zinc superoxide dismutase(CuZnSOD), an important metal enzyme to defense oxidative damage, is a member of superoxide dismutase(SODs) family. It can be ambulant to clear superoxide radical, improve antioxidant capacity of the body, and further improve health and meat quality. In order to explore the possibility to generate transgenic pigs by sperm carrier method mediated by magnetic nanoparticles, and further research the mechanism of how CuZnSOD gene effect the meat quantity, CuZnSOD transgenic pigs were constructed in this study. F1 and F2 generation individuals were detected by PCR, qRT-PCR and western blot. Exogenous gene copy number in the four slaughtered transgenic positive pigs were estimated by absolute qPCR. Meanwhile, we also verify the effect of CuZnSOD gene on antioxidant capacity and other meat quality traits. The main results are as follows:(1) 3 Yorkshire sows were uesd to produce F1 generation individuals. F1 generation individuals were obtained by artificial insemination on the basis of the successful recombinant vector incubated with magnetic nanoparticles and semen, respectively. A total of 43 pigs in F1 generation were produced, in which 13 were positive. The positive rate was 30.23%. Compared with the negative group, the positive group up-regulated the expression levels of CuZnSOD mRNA in muscle(P<0.05), liver(P>0.05), backfat(P>0.05), lung(P<0.05) and kidney(P>0.05) tissues in F1 generation. In addition, the positive group improved the expression levels of CuZnSOD protein in muscle(P<0.05), liver(P<0.05) backfat(P>0.05), lung(P>0.05) and kidney(P>0.05) tissues when compared with the negative group. Exogenous gene copy number in the four slaughtered transgenic positive pigs were estimated by absolute qPCR, and the exogenous gene copy number was 25.89, 80.61, 106.69 and 83.03, respectively.(2) 44 pigs in F2 generation were produced by 3 positive transgenic pigs of F1 generation, in which 11 were positive. The positive rate was 25.00%. Compared with the negative group, the positive group up-regulated the expression levels of CuZnSOD mRNA in muscle(P<0.05), liver(P<0.05) and backfat(P>0.05) tissues in F2 generation. And the relative expression levels of CuZnSOD protein in muscle tissues were significantly improved(P<0.05) in the positive group compared with the negative group.(3) The measurement results of meat quality in F1 generatio n showed that: compared with the negative group, the positive group was significantly increased in muscle SOD1 d and SOD2 d activity(P<0.05), but decreased in muscle drip loss, the content of MDA1 d and MDA2d(P<0.05), respectively. The measurement results of meat quality in F2 generation showed that: the positive group were significantly increased in muscle SOD1 d, SOD2 d and SOD3 d activity(P<0.05), but significantly decreased in muscle drip loss, cooking loss and the content of MDA1 d and MDA2d(P<0.05) when compared with the negative group. The serum biochemical indexes in F2 generation showed that the activity of ALP and the content of TP were significantly reduced(P<0.05) in the positive group compared with the negative group.In this study, CuZnSOD transgenic pigs were successfully generated by sperm carrier method mediated by magnetic nanoparticles. And the exogenous gene can be inherited and expressed in F2 generation. Meat quality traits, including antioxidant capacity and water-holding capacity, were improved in the positive transgenic pigs.