快速生长转gh黄河鲤饲料蛋白质需求量及其利用机制研究

Recently, the “all-fish” growth hormone transgenic Atlantic salmon has been approved to be farmed for human consumption by FDA, which was not only a breakthrough for industrialization of transgenic animals, but shedding light on our “all-fish” gh-transgenic common carp to be commercialized cultivation in China in the future. GH-transgenic carp exhibited growth enhancement performance, accelerated feeding motivation, higher feed conversion efficiency, and its energy budget is also different from non-transgenic carp. In aquaculture, the optimum dietary protein requirements for GH-transgenic carp should be determine first to achieve the best growth at the fully utilization of dietary protein as well as to minimase the residual feed. In this study, we will choose GH-transgenic carp at juvenile and the puberty onset stages as experimental objects, both of which are important developmental periods associated with survival, growth and energy allocation for transgenics. We will find out the relationship between the protein level and the survival, growth, feed utilization, body composition and nutrient metabolism and regulation of transgenics. Consequently, the optimum dietary protein requirements will be determined. And it also gives clues to elucidate the regulatory mechanism for high efficiency utilization of dietary protein in GH-transgenic carp.

最近美国FDA批准转全鱼gh大西洋鲑上市，实现了转基因动物产业化的历史性突破，也为我们自主研制的转全鱼生长激素基因快速生长黄河鲤（下称转gh黄河鲤）在我国产业化投射了希望的曙光。转gh鱼生长快，摄食、饵料转化效率及能量分配等特性与对照鱼显著不同；在养殖生产中，必须确定牠对饲料蛋白质的适宜需求量，以达到快速生长性状的充分发挥、饲料蛋白的充分利用以及尽量减少剩余饵料污染的统一。为此，本项目以我们自主培育的转gh黄河鲤为材料，选择与存活、生长和能量分配相关的幼鱼和青春启动期两个重要生长阶段为切入点，研究不同饲料蛋白质水平与转gh黄河鲤的存活、生长、饵料利用、鱼体生化组成、营养物代谢与调控的关系，确定转gh黄河鲤对饲料蛋白质的适宜需求量，初步揭示转全鱼gh基因鱼高效利用饲料蛋白质的调控机制。

本项目针对转gh基因黄河鲤饲料蛋白质需求量及其利用机制开展研究， 比较分析了转gh基因黄河鲤及对照鲤在幼鱼和青春启动期生长阶段的饲料消化、吸收、代谢的差异。发现幼鱼阶段，转gh黄河鲤和对照鱼的最适蛋白需求均为44%左右，转gh黄河鲤摄食不同蛋白含量的饲料其生长速度、饲料效率、摄食量及蛋白质效率均高于对照鲤，且生长速度和饲料效率随着饲料蛋白质的升高而升高。青春启动阶段，转gh黄河鲤的最适蛋白需求为35.4%，对照鱼的最适蛋白需求为31.6%，转gh黄河鲤的摄食率、生长速度、饲料效率、蛋白质效率均显著高于对照鱼。. 转gh基因黄河鲤高效饲料利用的机制研究表明，转gh基因黄河鲤肠道消化、吸收、转运营养物质的能力均显著强于对照鲤。转gh基因黄河鲤肝脏利用糖类、脂类的能力强于对照鲤。转gh黄河鲤血浆葡萄糖含量、谷丙转氨酶、谷草转氨酶及甘油三酯含量高于对照鱼，血浆总胆固醇、低密度脂蛋白和高密度脂蛋白含量均低于对照鱼。转gh黄河鲤肝脏蛋白合成相关基因tor、s6k1的表达量高于对照鱼，蛋白分解相关基因ulk1的表达量低于对照鱼。. 本项目获得了转gh基因黄河鲤在幼鱼和青春启动期生长阶段的最适蛋白需求量，初步揭示了转gh基因黄河鲤饲料高效利用的机制；为转gh基因黄河鲤的产业化养殖提供了关键的饲料配方参数，对于鱼类营养学和遗传育种研究具有理论意义和应用价值。