Wu Kun, Cleveland Beth M, Portman Mark, Sealey Wendy M, Lei Xin Gen
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
USDA/ARS National Center for Cool and Cold Water Research, Leetown, WV 25430, USA.
Antioxidants (Basel). 2020 Dec 27;10(1):16. doi: 10.3390/antiox10010016.
Microalgal docosahexaenoic acid (DHA) and astaxanthin (AST) may substitute for fish oil and synthetic AST in aquafeeds. This study explored the effects and mechanisms of those substitutions on AST metabolism and redox status of rainbow trout fed plant protein meal (PM)- or fishmeal (FM)-based diets. Two parallel experiments (PM vs. FM) were performed with 612 juvenile rainbow trout for 16 weeks as a 2 × 3 factorial arrangement of treatments with two AST sources (synthetic (SA) vs. microalgal (AA), at 80 mg/kg) and three levels (0, 50, and 100%) of fish oil substitutions with DHA-rich microalgae. The fish oil substitutions exhibit main effects ( < 0.05) and/or interactive effects ( < 0.05) with the source of AST on AST deposition, malondialdehyde and glutathione concentrations, and mRNA levels and activities of major redox enzymes (glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), and superoxide dismutase (SOD)) in the muscle and liver of trout fed both diet series. The AST source produced only differences in tissue AST deposition ( < 0.05) and number of metabolites. In conclusion, the substitutions of fish oil by the DHA-rich microalgae exerted more impacts than those of SA by AA on redox status and functional expression of antioxidant enzymes in the tissues of rainbow trout.
微藻二十二碳六烯酸（DHA）和虾青素（AST）可替代水产饲料中的鱼油和合成虾青素。本研究探讨了这些替代物对以植物蛋白粉（PM）或鱼粉（FM）为基础日粮的虹鳟鱼AST代谢和氧化还原状态的影响及机制。以612尾虹鳟幼鱼进行了两个平行实验（PM组与FM组），为期16周，采用2×3析因设计处理，有两种AST来源（合成虾青素（SA）与微藻虾青素（AA），添加88添加量为80 mg/kg），以及用富含DHA的微藻替代鱼油的三个水平（0%、50%和100%）。在两个日粮系列喂养的虹鳟鱼的肌肉和肝脏中，鱼油替代物与AST来源对AST沉积、丙二醛和谷胱甘肽浓度以及主要氧化还原酶（谷胱甘肽还原酶（GR）、谷胱甘肽过氧化物酶（GPX）、谷胱甘肽S-转移酶（GST）和超氧化物歧化酶（SOD））的mRNA水平和活性表现出主效应（P<0.05）和/或交互效应（P<0.05）。AST来源仅在组织AST沉积（P<0.05）和代谢物数量上产生差异。总之，富含DHA的微藻替代鱼油对虹鳟鱼组织氧化还原状态和抗氧化酶功能表达的影响比AA替代SA的影响更大。
