Table_8_Integrated Analysis of Metabolomics and Transcriptomics for Assessing Effects of Fish Meal and Fish Oil Replacement on the Metabolism of Rainbow Trout (Oncorhynchus mykiss).xlsx

Reducing dependency on dietary fish meal (FM) and fish oil (FO) is extremely important for the sustainable development of the aquaculture industry. However, the metabolic consequences and mechanisms underlying the replacement of dietary FM and FO by terrestrial proteins (TPs) and lipids remain unclear. To reveal the effects of replacing dietary FM and/or FO on the metabolic changes, the integrated analysis of metabolomics and transcriptomics were employed to evaluate the changes in metabolites and genes of rainbow trout (Oncorhynchus mykiss) feeding different experimental diets. Four diets were formulated for the 84-day duration of the experiment: control group (FMFO), FM and vegetable oil (FMVO), terrestrial protein and FO (TPFO), and terrestrial protein and vegetable oil (TPVO). Integrated metabolomic and transcriptomic analyses revealed the significant difference in the metabolic pathways of O. mykiss among the three replacement schemes, i.e., single replacement of dietary FM by TP, single replacement of dietary FO by VO, and combined replacement of FM by TP and FO by VO. The combined replacement of FM and FO by TP and VO, respectively, disturbed immune function, energy metabolism, cellular protein biosynthesis capacity, and lipid metabolism of O. mykiss. The reduction of antioxidant capacity was only observed in individuals feeding diets with replacement of FM by TP. Furthermore, as soon as the dietary FM and/or FO were reduced, cellular protein biosynthesis ability was suppressed and accompanied by higher energy consumption in response to fluctuations of dietary quality, resulting in reduced growth performance. Interestingly, adenylosuccinate and adenosine monophosphate involved in purine metabolism were induced by both individual and combined replacement of FM and FO by TPs and lipids, respectively. It suggested that these two metabolites might be potential biomarkers for O. mykiss fed diets with reduction of FM and/or FO. This study constitutes a new understanding of the molecular and metabolic mechanisms of O. mykiss in response to the replacement of dietary FM and/or FO by TP and/or VO, respectively, and built a theoretical basis for further improvement of aquafeed formulation and sustainable development of aquaculture.

降低日粮鱼粉（fish meal, FM）与鱼油（fish oil, FO）的依赖程度，对于水产养殖业的可持续发展至关重要。然而，用陆源蛋白（terrestrial proteins, TPs）与脂质替代日粮鱼粉和鱼油的代谢效应及潜在机制仍不明晰。为揭示替代日粮鱼粉和/或鱼油对机体代谢变化的影响，本研究采用代谢组学与转录组学整合分析方法，对饲喂不同实验日粮的虹鳟（Oncorhynchus mykiss）的代谢物与基因表达变化进行评估。实验周期为84天，共设置4种实验日粮：对照组（FMFO，全鱼粉鱼油日粮）、鱼粉+植物油（FMVO）组、陆源蛋白+鱼油（TPFO）组，以及陆源蛋白+植物油（TPVO）组。代谢组与转录组整合分析显示，三种替代方案——即单用陆源蛋白替代日粮鱼粉、单用植物油替代日粮鱼油、联合用陆源蛋白替代鱼粉与植物油替代鱼油——虹鳟的代谢通路存在显著差异。联合用陆源蛋白替代鱼粉、植物油替代鱼油，会扰乱虹鳟的免疫功能、能量代谢、细胞蛋白质合成能力与脂质代谢。仅在饲喂陆源蛋白替代鱼粉日粮的个体中，可观察到抗氧化能力下降。进一步研究发现，当日粮鱼粉和/或鱼油被替代时，细胞蛋白质合成能力会受到抑制，并伴随因日粮品质波动引发的更高能量消耗，最终导致生长性能下降。有趣的是，参与嘌呤代谢的腺苷酸琥珀酸与一磷酸腺苷（adenosine monophosphate, AMP），分别在单一替代与联合替代鱼粉和鱼油的处理中被诱导上调。这提示这两种代谢物或可作为饲喂低鱼粉和/或鱼油日粮的虹鳟的潜在生物标志物。本研究加深了对虹鳟在分别接受陆源蛋白和/或植物油替代日粮鱼粉和/或鱼油后的分子与代谢机制的认知，为进一步优化水产饲料配方及水产养殖业的可持续发展奠定了理论基础。