EFFECTS OF RECOMBINANT GH ON GROWTH, BLOOD BIOCHEMISTRY, AND BODY COMPOSITION OF JUVENILE DABRY'S STURGEON ACIPENSER DABRYANUS

In this study, Dabry's sturgeon (Acipenser dabryanus) mature growth hormone (GH) cDNA sequence was constructed with prokaryotic expression vector pET-32a and transfected into E. coli BL21 (DE3). Recombinant A. dabryanus GH protein (rAdGH) was expressed in E. coli cells as an inclusion body. The purified rAdGH were used as a feed additive to determine the effects of rAdGH on growth, blood biochemistry, and body composition of Dabry's sturgeon for an eight-weeks experiment with four groups including control group (0), low-treated group (10 mg/kg), middle-treated group (50 mg/kg), and high-treated group (100 mg/kg). Results showed that the complementary rAdGH improved weight gain rate, feed efficiency, hepatosmatic index, viscera index and growth performance in the low-treated group. In addition, the low level of rAdGH treatment promoted almost all blood indexes except blood glucose. Suitable level of exogenous GH improved the content of protein and moisture in the liver and muscle, and reduced the fat content in the liver and muscle. In general, its effects on growth and metabolism were dosage-dependent. Low level rAdGH treatment significantly improved the metabolism and growth of fish, and promoted deposition of liver protein and fat consumption. However, a higher dose induced metabolic disease, inhibited growth performance, trigged liver damage and changed components. These results suggest that the recombinant GH would benefit the application of recombinant GH in sturgeon culture.