The present study was conducted to replace fish meal with alternative plant protein sources in aquafeeds. Therefore, soybean meal (SBM), corn gluten meal (CGM), and mix of SBM + CGM were used as alternatives to fish meal (FM) with or without betaine (B) in Nile tilapia diets. Positive control diet using FM and six other diets were formulated to contain SBM, SBM + B, CGM, CGM + B, SBM + CGM, or SBM + CGM + B. Dietary B improved fish growth and body protein content in comparison to the control and equal to fish fed FM-based diet. Reduced FCR and body fat content were observed in the case of fish fed FM, SBM + B, CGM + B, or SBM + CGM + B diets. The survival rate was significantly increased in the group of fish fed SBM + CGM + B when compared to fish fed CGM diet (P = 0.013) while no significant differences were reported among the other groups (P > 0.05). Markedly increased intestinal villi length and the number of goblet cells were found in FM, SBM+B, CGM+B, and SBM+CGM+B groups (P < 0.05). Hemoglobin, blood total protein, and IGF-1 gene expression were significantly (P < 0.05) increased in fish fed FM, CGM+B, SBM+CGM, and SBM+CGM+B diets, while fatty acid synthetase (FAS) and lipoprotein lipase (LPL) were downregulated. The highest RBCs, WBCs, and globulin were observed in fish fed SBM + CGM + B diet, while the lowest number was found in the fish fed CGM diet. To sum up, B supplementation in tilapia diets acted synergistically with SBM, CGM, or both SBM + CGM to improve the growth, intestinal morphometrical indices, hemoglobin, and total protein and IGF-1 as well as decreased FCR, FAS, and LPL.

进行本研究是用水产饲料中的替代植物蛋白源代替鱼粉。因此，在尼罗罗非鱼日粮中，豆粕（SBM），玉米面筋粉（CGM）以及SBM + CGM的混合物可替代含或不含甜菜碱（B）的鱼粉（FM）。使用FM和其他六种饮食的阳性对照饮食配制为含有SBM，SBM + B，CGM，CGM + B，SBM + CGM或SBM + CGM +B。与对照相比，饮食B改善了鱼的生长和身体蛋白质含量等同于以FM为基础的鱼饲料。在以FM，SBM + B，CGM + B或SBM + CGM + B饮食喂养的鱼中，观察到FCR和身体脂肪含量降低。与饲喂CGM的鱼相比，饲喂SBM + CGM + B的鱼的成活率显着提高（P = 0.013），而其他组之间无显着差异（P  > 0.05）。FM，SBM + B，CGM + B和SBM + CGM + B组的肠绒毛长度显着增加，杯状细胞数量增加（P  <0.05）。 FM，CGM + B，SBM + CGM和SBM + CGM + B饲喂的鱼，脂肪酸合成酶（FAS）和脂蛋白的血红蛋白，血液总蛋白和IGF-1基因表达显着增加（P <0.05）脂酶（LPL）下调。饲喂SBM + CGM + B日粮的鱼中RBC，WBC和球蛋白最高，而饲喂CGM日粮的RBC，WBC和球蛋白最低。综上所述，罗非鱼日粮中补充B与SBM，CGM或SBM + CGM协同作用，以改善生长，肠形态指标，血红蛋白，总蛋白和IGF-1并降低FCR，FAS和LPL。