A feeding experiment was carried out to compare the effects of dietary synthetic astaxanthin and Haematococcus pluvialis on growth, antioxidant capacity, immune response and hepato-morphology of Oncorhynchus mykiss under cage culture with flowing freshwater. Three isonitrogenous and isolipidic diets were formulated with or without synthetic astaxanthin and H. pluvialis and were administered to O. mykiss for 56 days. The results showed that growth performance and muscle lipid of O. mykiss were significantly improved by diet supplemented with synthetic astaxanthin or H. pluvialis. Feed coefficient ratio of O. mykiss fed the diets supplemented with synthetic astaxanthin or H. pluvialis was lower than that of fish fed the control diet. Besides, dietary synthetic astaxanthin or H. pluvialis supplementation significantly improved dorsal muscle pigmentation of O. mykiss. The beneficial effects on growth performance and pigmentation were more evident in synthetic astaxanthin than that in H. pluvialis. Synthetic astaxanthin or H. pluvialis supplementation activated Nrf2-ARE pathway, enhanced superoxide dismutase activity and decreased MDA content in the liver. Furthermore, synthetic astaxanthin or H. pluvialis improved the non-specific immunity by activating lysozyme and complement system, exerted anti-inflammatory activity by inhibiting the expression of pro-inflammatory cytokines (interleukin 1β, interleukin 8 and tumor necrosis factor-α) and improved the liver morphology. Based on these findings, dietary synthetic astaxanthin and H. pluvialis supplementation have a beneficial effect on the growth performance, antioxidant capacity, innate immune response and liver health of O. mykiss.

进行了饲喂试验，比较了日粮合成虾青素和雨生红球藻对淡水流水网箱养殖鲇鱼生长、抗氧化能力、免疫反应和肝形态的影响。三种等氮和等脂饮食配制有或没有合成虾青素和雨生红球藻，并给予O. mykiss 56 天。结果表明，在日粮中添加合成虾青素或雨生红虾可显着提高O. mykiss的生长性能和肌肉脂质。O. mykiss的饲料系数比喂食添加了合成虾青素或雨生红藻的日粮的鱼低于喂食对照日粮的鱼。此外，日粮中添加合成虾青素或雨生红球藻显着改善了O. mykiss的背肌色素沉着。合成虾青素对生长性能和色素沉着的有益影响比雨生红虾更明显。合成虾青素或雨生红球藻补充剂可激活 Nrf2-ARE 通路，增强超氧化物歧化酶活性并降低肝脏中的 MDA 含量。此外，合成虾青素或H. pluvialis通过激活溶菌酶和补体系统提高非特异性免疫，通过抑制促炎细胞因子（白细胞介素1β、白细胞介素8和肿瘤坏死因子-α）的表达发挥抗炎活性，改善肝脏形态。基于这些发现，日粮中添加合成虾青素和雨生红球藻对O. mykiss的生长性能、抗氧化能力、先天免疫反应和肝脏健康具有有益影响。