GH重组蛋白对达氏鲟生长、血液生化和体组成的影响

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

为研究生长激素(GH)重组蛋白对达氏鲟生长、代谢及鱼体肝组分的影响,构建了GH成熟肽融合原核表达载体pET32a-AdGH,并将其在宿主菌BL21(DE3)中诱导表达,重组蛋白rAdGH以包涵体的形式存在。设置了4个试验组,分别在鲟鱼商品饲料中添加含量为0(对照组)、10(低处理组)、50(中处理组)和100mg/kg(高处理组)的粉状rAdGH,连续投喂8周。结果表明,低水平rAdGH添加能够显著促进鱼体生长,提高特定生长率,降低饵料系数,提高肝体比和脏体比;进一步的分析表明,低水平rAdGH添加可提高除血糖外所有测定的血液指标数值,反映了机体代谢水平的增强。各浓度rAdGH的添加均能提高鱼体肝和肌肉中蛋白质、水分含量,降低脂肪含量。rAdGH对鱼体生长和代谢的影响可能与其剂量相关,低水平的添加可显著增强鱼体代谢水平,加快肝中蛋白质的沉积与脂肪的消耗,促进鱼体生长;高水平的添加进一步增强其代谢水平,但其促生长的功能下降,部分血液指标异常,肝组分异常,疑似肝损伤。研究探索了鲟鱼重组生长激素的生长调控功能,为重组生长激素在鲟鱼养殖中的应用提供了基础。

In this study, Dabry＇s sturgeon（Acipenser dabryanus） mature growth hormone（GH） c DNA sequence was constructed with prokaryotic expression vector pET-32 a and transfected into E. coli BL21（DE3）. Recombinant A.dabryanus GH protein（r Ad GH） was expressed in E. coli cells as an inclusion body. The purified r Ad GH were used as a feed additive to determine the effects of r Ad GH 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 r Ad GH improved weight gain rate, feed efficiency, hepatosmatic index, viscera index and growth performance in the lowtreated 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.