To investigate the effects of dietary tributyrin (TB) on grass carp (Ctenopharyngodon idella), five diets were prepared with supplementing TB at 0 (TB-0), 200 (TB-200), 400 (TB-400), 600 (TB-600) and 800 (TB-800) mg/kg and then fed to grass carp with initial body weight of 17.0 Â± 0.2 g for 60 days. TB-400 and TB-600 groups presented higher weight gain, higher retention of protein, lipid, ash and lower feed conversion ratio than TB-0 group (p < .05), and TB-400 group also showed higher digestibility of dry matter and protein as well as intestinal amylase activity than TB-0 group (p < .05). Compared with the control, the serum superoxide dismutase activity was increased, and malondialdehyde content was decreased in TB-400 and TB-600 groups (p < .05), while TB-200 and TB-400 groups presented higher serum lysozyme activity than TB-0 group (p < .05). The villus height in foregut was increased in all the tributyrin-supplemented groups, but the villus height in midgut was increased only in TB-400 and T-600 groups (p < .05). The relative abundance of Erysipelatoclostridium tended to increase, and Aeromonas tended to decrease in TB-400 group. In conclusion, dietary tributyrin promoted the growth and feed utilization, enhanced serum antioxidant capacity and improved intestinal health of grass carp. Based on growth performance, the appropriate dietary supplementation of tributyrin is 443.5 mg/kg by using quadratic regression analysis.

中文翻译：

---

日粮添加三丁酸改善草鱼 (Ctenopharyngodon idella) 的生长、饲料利用率和肠道组织学

为研究日粮三丁酸甘油酯 (TB) 对草鱼 ( Ctenopharyngodon idella ) 的影响，制备了五种添加 TB 的日粮，分别为 0 (TB-0)、200 (TB-200)、400 (TB-400)、600 (TB) -600) 和 800 (TB-800) mg/kg，然后饲喂初始体重 17.0 ± 0.2 g 的草鱼 60 天。与 TB-0 组相比，TB-400 和 TB-600 组的增重更高，蛋白质、脂质、灰分的保留率更高，饲料转化率更低（p  < .05），并且 TB-400 组的干物质消化率也更高和蛋白质以及肠淀粉酶活性均高于 TB-0 组 ( p  < .05)。与对照组相比，TB-400和TB-600组血清超氧化物歧化酶活性升高，丙二醛含量降低（p < .05)，而 TB-200 和 TB-400 组的血清溶菌酶活性高于 TB-0 组 ( p  < .05)。前肠绒毛高度在所有添加三丁酸甘油酯的组中均增加，但中肠绒毛高度仅在 TB-400 和 T-600 组中增加（p  < .05）。TB-400组丹毒梭菌相对丰度呈上升趋势，气单胞菌呈下降趋势。总之，日粮三丁酰甘油促进草鱼的生长和饲料利用率，增强血清抗氧化能力，改善草鱼肠道健康。根据生长性能，通过二次回归分析，三丁酸甘油酯的适宜日粮添加量为443.5 mg/kg。