Our trial was performed to investigate the effect of fully fermented yeast Sacharomyces cerevisiae (Hilyses, ICC Company, Brazil) on the growth performance and immune response of Oreochromis niloticus. In this study, a total of 270 O. niloticus (50.7 ± 0.8 g) were randomly divided into 3 groups in triplicates. The control group was fed on the basal diet while the other two groups were fed on a basal diet supplemented with 0.2% and 0.4% of Hilyses. The trial period extended for 2 months. At the end of the feeding trial, oxidant and antioxidant parameters (MDA, catalase, and glutathione reductase), some innate immunological parameters and immune-related gene expression were measured. Histological examination of liver, spleen, kidney, and intestine was performed. Further, fish groups were challenged against Gram-negative and Gram-positive bacteria; A. hydrophila and L. garvieae. The results revealed significant improvement (p < 0.05) in growth performance and feed utilization in Hilyses-treated groups versus the control group. Blood parameters and liver and kidney functions of Hilyses-supplemented groups were similar to those of the control group. The histological findings of treated groups showed normal tissue structure with multiple focal lymphoid aggregations in the spleen, kidney, and intestine. Both levels of Hilyses successfully enhanced phagocytic activity/index, lysozyme activity, and gene expression of TNF-α, and IL-1β. Fish group fed on 0.4% Hilyses exhibited the highest expression of IL-1β and the least mortality percentages post challenges. Thus, dietary supplementation of Hilyses could promote the growth performance and immunity and increase the resistance of O. niloticus against diseases.

中文翻译：

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日粮发酵酿酒酵母对培养的尼罗罗非鱼生长性能，氧化应激参数和免疫反应的影响。

我们进行了一项试验，以研究完全发酵的啤酒酵母（Sacharomyces cerevisiae）（Hilyses，ICC Company，巴西）对尼罗罗非鱼的生长性能和免疫反应的影响。在这项研究中，总共270个尼罗罗非鱼（50.7±0.8 g）被随机分为3组，一式三份。对照组以基础饮食喂养，而其他两组则以基础饮食喂养，基础饮食中添加了0.2％和0.4％的Hilyses。试用期延长了2个月。在喂养试验结束时，测量了氧化剂和抗氧化剂参数（MDA，过氧化氢酶和谷胱甘肽还原酶），一些先天免疫学参数和免疫相关基因的表达。进行肝，脾，肾和肠的组织学检查。此外，鱼类群体受到革兰氏阴性和革兰氏阳性细菌的攻击；一种。嗜水菌和L. garvieae。结果显示，与对照组相比，Hilyses治疗组的生长性能和饲料利用率显着改善（p <0.05）。溶血酶补充组的血液参数和肝肾功能与对照组相似。治疗组的组织学发现显示正常组织结构，在脾，肾和肠中有多个局灶性淋巴样聚集。两种水平的裂解酶均成功地增强了吞噬活性/指数，溶菌酶活性以及TNF-α和IL-1β的基因表达。饲喂0.4％裂解液的鱼群在攻击后表现出最高的IL-1β表达，而死亡率最低。因此，日粮中添加Hilyase可以促进其生长性能和免疫力，并增加O的抵抗力。