饲料中植物油替代鱼油对中华绒螯蟹卵巢发育过程中脂质代谢和营养品质的影响及其机理分析

The short supply of marine fish oil has been one of the major challenges for aquafeed industry, which drive the study of fish oil replacement urgent. Chinese mitten crab (Eriocheir sinensis) is an important aquaculture species in China. Our previous study has shown the dietary substitution of fish oil with vegetable oil has the negative impact on the ovarian development and nutritional quality of this species, which may be related to lipid metabolism. The current project is designed to foucus on this issue. Firstly, the comparative transcriptomics and lipidomics will be investigated on crab tissues of important development stages during the ovarian development of E. sinensis, which would be expected to find the potential lipid molecules/metabolites and differentially expressed genes (DEGs) involved in the lipid metabolism and ovarian development. Then, the comprehensive study would be conducted to evaluate the effects of dietary fish oil replacement by the blending vegetable oils (soybean oil and rapeseed oil) on ovarian development, lipid metabolism, immune performance and nutritional quality for the female E.sinensis. The further trans-omics (transcriptomics, proteomics and lipidomics) methods will be used to screen the DEGs, differential lipid molecules/metabolites and differential proteins, responding to the dietary fish oil replacement. Based on the previous results, the possible relationships would be studied and validated between the key lipid molecules/metabolites and ovarian development, immune performance as well as the nutritional quality for E.sinensis feeding the diets with/without the fish oil replacement. Finally, the potentionally regulatory pathway and its network of lipid metabolism would be expected to discuss and establish for the crabs under the feeding with/without the dietary fish oil replacement during the ovarian development of E.sinensis. The expected results of this project could be not only improve our understanding for the mechanisms of lipid metabolism and ovarian development, but also provide the basic information for the dietary fish oil replacment, fatttening feed development and quality improvement for the female E.sinensis.

鱼油资源短缺是水产饲料业面临的重大挑战之一，开展植物油替代鱼油研究迫在眉睫。河蟹是我国重要的养殖种类，饲料中鱼油大量被植物油替代对其卵巢发育和营养品质造成了负面影响，这可能与其脂质代谢相关，本项目拟对这个问题进行深入研究。项目首先研究河蟹卵巢发育过程中几个关键阶段的转录组学和脂质组学，筛选与脂质代谢和卵巢发育相关的差异表达基因及脂质分子；在此基础上，系统研究饲料中植物油混合替代(常用的豆油和菜籽油)鱼油对其卵巢发育、脂质代谢、免疫性能和营养品质的影响；进一步通过脂质组学、转录组学和蛋白组学研究，筛选植物油替代鱼油条件下的差异表达基因、差异蛋白和差异脂质分子/代谢物，研究和验证关键脂质分子与卵巢发育、免疫性能、营养品质的可能关系，探讨鱼油替代对河蟹脂质代谢的影响机制和调控网络。预期研究结果对深入理解河蟹的脂质代谢调控、卵巢发育机制、育肥饲料开发和营养品质调控均具有重要的理论和现实意义

鱼油资源短缺是水产饲料业面临的重大挑战之一，开展植物油替代鱼油研究迫在眉睫。河蟹是我国重要的养殖种类，饲料中鱼油大量被植物油替代对其卵巢发育和营养品质造成了负面影响，这可能与其脂质代谢相关，本项目针对这个问题进行了较系统的研究。项目首先研究河蟹卵巢发育过程中几个关键阶段的转录组学、代谢组、脂质组学和蛋白组，筛选与脂质代谢和卵巢发育相关的差异表达基因及脂质分子；在此基础上，研究饲料中植物油混合替代鱼油对其卵巢发育、脂质代谢、免疫性能和营养品质的影响；进一步筛选植物油替代鱼油条件下的差异表达基因和差异代谢物，研究了河蟹关键脂质代谢基因（DGAT, GPAT和SOAT）对河蟹雌体卵巢发育和脂质代谢的影响，并通过RNAi进行了验证这些基因的功能；最后，通过配制三种实用饲料（全鱼油组、优化的鱼油替代组和全植物油组）投喂生殖蜕壳后的河蟹雌体，比较了三种饲料和育肥时间对雌体育肥性能、可食率、营养组成和风味物质含量影响。结果表明：1.河蟹卵巢发育过程中卵巢中的磷脂、甘油三酯和胆固醇酯含量均显著上升，肝胰腺中的甘油三酯含量显著下降，卵巢中TAG: 52:3、TAG: 54:5、TAG：54:6、PC:34:1、PC: 38:6和PC:40:6含量上升显著。2.基于育肥养殖性能、卵巢发育、脂质代谢、免疫性能、肠道微生物和营养品质等确定雌体育肥饲料中适宜的植物油替代鱼油水平为50%左右，豆油和菜籽油的适宜比例为1:1。3. 植物油替代鱼油影响肝胰腺中甘油三酯分解代谢和前列腺素代谢途径，影响卵巢中脂肪酸代谢和胆固醇沉积的基因表达，影响胆固醇沉积。4. GPAT和DGAT不同亚型在肝胰腺和卵巢中的TAG积累作用不同，干扰GPAT1基因会直接影响下游的基因表达和TAG含量。这些研究结果对深入理解河蟹的脂质代谢调控、卵巢发育机制、育肥饲料开发和营养品质调控均具有重要的理论和现实意义。