Effects of soybean protein on intestinal morphology and main _blood biochemical parameters of Ctenopharyngondon idellus | 大豆蛋白对草鱼肠道组织及血液主要生化指标的影响

Chinese. 研究大豆蛋白对草鱼肠道组织及血液主要生化指标的影响，为草鱼人工配合饲料的合理优化提供依据。以初始体质量为（50.63±0.43）g的健康草鱼（Ctenopharyngodon idellus）为试验对象，在室内单循环控温养殖系统中进行8周生长试验。以鱼粉为动物蛋白源，用去皮豆粕为植物蛋白源，用去皮豆粕分别替代0%（CK），15%，30%，45%和60%的鱼粉，配制成5种等蛋白（约300 g/kg）、等能（15.6 MJ/kg）的日粮,分别饲喂各组草鱼，研究大豆蛋白对草鱼肠道组织及血液主要生化指标的影响。60%大豆蛋白替代组草鱼的前肠、后肠皱襞高度极显著低于对照组（P＞0.05），中肠皱襞高度显著低于对照组（P＞0.05）。同时，45%和60%大豆蛋白替代组前肠和后肠肠道结构组织完整性均被破坏，部分肠绒毛脱落，部分上皮细胞与固有层分离，固有层结缔组织疏松，固有层变宽。各组草鱼血液中血糖、尿素氮、总胆固醇、甘油三酯、总蛋白、白蛋白和球蛋白浓度及谷草转氨酶、谷丙转氨酶活性差异均不显著（P＞0.05）。在本试验条件下，体质量50~100 g草鱼的配合饲料蛋白水平为 300 g/kg，大豆蛋白适宜替代量为45%，过量添加大豆蛋白会使草鱼肠道完整性被破坏。

English. The effects of dietary soybean protein on intestinal morphology and main blood biochemical parameters were investigated to offer basis to optimize the artificially formulated feed of Ctenopharyngondon idellus in this study. A growth trial was conducted on juvenile fish with initial body weight of (50.63±0.43) g for 8 weeks at controlled temperature in single recirculating system. Fish meal and dehulled soybean meal were used as protein source. Five isonitrogenous (300 g/kg) and isoenergetic (15.6 MJ/kg) diets, with dehulled soybean meal replacing level 0% (CK), 15%, 30%, 45% and 60% of fish meal protein, were formulated to feed juveniles to investigate the effects of dietray soybean protein level on intestinal tissue and main biochemical parameters in blood of C. idellus. The results indicated that,when soybean protein replaced fish meal by 60%, the entero-plica height of anterior intestine and posterior intestine significantly decreased (P＜0.01), the entero-plica height of mid-intestine in 60% group was significantly lower than that in control group in C. idellus (P＜0.05). Meanwhile, the intact morphology of anterior intestine and posterior intestine in 45% and 60% group of C. idelluswere damaged. The part of intestinal villi was shed, the part of epithelial cells and proper layer were separated, and the proper layer became wider. In addition, the contents of blood sugar, urea nitrogen, total cholesterol triglyeride, glutamic-oxal (o) acetic transaminase, glutamic-pyruvic transaminase, total protein, albumen and globulin in blood had no significant differences in each group of C. idellus (P＞0.05). Therefore, the protein content was 300 g/kg in the formula of C. idellus (50C100 g) and the proper replacement level was 45%. Over supplementation of soybean protein would damage the structural integrity of epithelial cells.