The present study was conducted to investigate the effect of fish meal replacement with Clostridium autoethanogenum protein (CAP) on growth performance, haemato-biochemistry, digestive capacity, antioxidant index, and histopathological examination of liver and intestine in largemouth bass (Micropterus salmoides). Seven experimental diets were formulated with CAP replacement of 0% (CAP0), 15% (CAP15), 27% (CAP27), 39% (CAP39), 51% (CAP51), 63% (CAP63) and 75% (CAP75) fish meal, respectively. Results showed that replacement of fish meal by CAP did not affect SR, FBW, WGR, SGR and CF. While the fish fed diets containing CAP displayed a higher PER and a lower FCR than the control group (P < 0.05). However, the CAP inclusion level did not statistically affect the whole-body composition (P > 0.05). Additionally, The ADC of dry matter and protein were improved by addition of CAP (P < 0.05), while corresponding ADC of lipid were not significantly changed among different groups (P > 0.05). The lipase and amylase activities were not dramatically altered in stomach (P > 0.05), but were significantly increased in intestine with dietary substitution level up to 39% (P < 0.05). Differently, the protease activity of fish fed CAP75 was higher than other groups in stomach and intestine (P < 0.05). In addition, the activities of T-AOC and SOD in serum, liver and intestine were elevated with dietary CAP level (P < 0.05), whereas MDA content displayed the opposite trend. Moreover, the increased TP, ALB, TC, TG and AST/ALT were observed in treatment groups. In addition, the villus length and width of hindgut were dramatically increased with increasing dietary substitution level up to 39%. Furthermore, no adverse effect on the hepatic histology was occurred when fed diet with substitution level below 63%. Overall, the optimal CAP replacement level was 49.80% with maximum weight gain rate of juvenile largemouth bass.

本研究旨在研究用自产乙醇梭菌蛋白 (CAP)替代鱼粉对大口黑鲈 ( Micropterus salmoides )生长性能、血液生化、消化能力、抗氧化指数和肝脏和肠道组织病理学检查的影响。用 0% (CAP0)、15% (CAP15)、27% (CAP27)、39% (CAP39)、51% (CAP51)、63% (CAP63) 和 75% (CAP75) 的 CAP 替代配制了七种实验饮食分别是鱼粉。结果表明用CAP替代鱼粉不影响SR、FBW、WGR、SGR和CF。而饲喂含 CAP 日粮的鱼表现出比对照组更高的 PER 和更低的 FCR（P < 0.05)。然而，CAP包含水平对全身成分没有统计学影响（P  > 0.05）。此外，添加CAP后干物质和蛋白质的ADC得到提高（P  < 0.05），而相应的脂质ADC在不同组间没有显着变化（P  > 0.05）。脂肪酶和淀粉酶活性在胃中没有显着改变（P  > 0.05），但在肠道中显着增加，膳食替代水平高达39％（P  < 0.05）。不同的是，饲喂CAP75的鱼在胃和肠中的蛋白酶活性高于其他组（P < 0.05)。此外，血清、肝脏和肠道中 T-AOC 和 SOD 的活性随着膳食 CAP 水平升高（P  < 0.05），而 MDA 含量显示出相反的趋势。此外，在治疗组中观察到增加的TP、ALB、TC、TG和AST/ALT。此外，随着日粮替代水平的增加，后肠绒毛的长度和宽度显着增加，最高可达 39%。此外，当饲喂替代水平低于 63% 的饮食时，对肝脏组织学没有不良影响。总体而言，最佳 CAP 替换水平为 49.80%，幼鱼增重率最大。