This study evaluated the effects of substituting fish meal with common soybean meal (SBM) or extruded soybean meal (ESBM) on growth, digestion, some nonspecific immune markers, and intestinal morphology in juvenile minnow Rhynchocypris lagowskii. In trial 1, five experimental diets were formulated with SBM replacing 0% (fish meal control; SBM0), 12.5% (SBM12.5), 25.0% (SBM25), 37.5% (SBM37.5), and 50.0% (SBM50) of the fish meal. Rhynchocypris lagowskii (6.81 ± 0.19 g) were randomly stocked in 100-L cylindrical plastic tanks and fed to satiation thrice daily for 56 d. After the feeding trial, there was no significant differences in weight gain ratio (WGR), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER), feed conversion ratio (FCR), and feed intake (FI) of the SBM0, SBM12.5, and SBM25 groups. But compared with the control group, WGR, SGR, and FI of the SBM37.5 and SBM50 groups were significantly decreased, FER and PER of the SBM50 group were significantly decreased, and FCR of the SBM50 group was significantly increased. Providing the SBM37.5 and SBM50 diets can significantly reduce the muscle protein content and protease activity of the hepatopancreas and intestine. Aspartate aminotransferase, alanine aminotransferase, lysozyme, and superoxide dismutase activities in the hepatopancreas decreased with increasing dietary SBM levels. Providing the SBM25, SBM37.5, and SBM50 diets caused atrophy, swelling, and rupture of the intestinal mucosal fold and separation of epithelial mucosa from the lamina propria. In trial 2, five experimental diets were formulated with ESBM replacing 0% (fish meal control; ESBM0), 12.5% (ESBM12.5), 25.0% (ESBM25), 37.5% (ESBM37.5), and 50.0% (ESBM50) of the fish meal. Rhynchocypris lagowskii (6.87 ± 0.02 g) were randomly stocked in 100-L cylindrical plastic tanks and fed to satiation thrice daily for 56 d. After the feeding trial, WGR, FI, SGR, FER, PER, and muscle crude protein content of the ESBM50 group were significantly decreased compared with the control group, and FCR of the ESBM50 group was significantly increased. Meanwhile, the hepatopancreas and intestinal protease activities and the hepatopancreas superoxide dismutase, lysozyme, aspartate aminotransferase, and alanine aminotransferase activities decreased with increasing dietary ESBM levels, and the ESBM50 group was significantly different than the control group. Providing the ESBM37.5 and ESBM50 diets caused atrophy and rupture of intestinal mucosal fold and separation of epithelial mucosa from the lamina propria. These results indicated that SBM could replace 12.5% of fish meal in juvenile R. lagowskii diets, while ESBM could replace 25% of fish meal.

中文翻译：

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用两种豆粕替代鱼粉对幼鱼生长、酶活性和肠道形态的影响

本研究评估了用普通豆粕 (SBM) 或膨化豆粕 (ESBM) 替代鱼粉对幼鱼Rhynchocypris lagowskii 的生长、消化、一些非特异性免疫标志物和肠道形态的影响。在试验 1 中，用 SBM 代替 0%（鱼粉对照；SBM0）、12.5% (SBM12.5)、25.0% (SBM25)、37.5% (SBM37.5) 和 50.0% (SBM50) 配制五种实验日粮的鱼粉。钩鱼(6.81 ± 0.19 g) 随机储存在 100 升圆柱形塑料罐中，每天喂食三次，持续 56 天。饲喂试验后，增重比（WGR）、比生长率（SGR）、饲料效率比（FER）和蛋白质效率比（PER）、饲料转化率（FCR）和采食量没有显着差异（ FI) 的 SBM0、SBM12.5 和 SBM25 组。但与对照组相比，SBM37.5和SBM50组的WGR、SGR和FI均显着降低，SBM50组的FER和PER显着降低，SBM50组的FCR显着升高。提供 SBM37.5 和 SBM50 饮食可以显着降低肝胰腺和肠道的肌肉蛋白质含量和蛋白酶活性。天冬氨酸氨基转移酶、丙氨酸氨基转移酶、溶菌酶、肝胰腺中的超氧化物歧化酶活性随着日粮 SBM 水平的增加而降低。提供 SBM25、SBM37.5 和 SBM50 饮食会导致肠黏膜皱襞萎缩、肿胀和破裂，以及上皮黏膜与固有层的分离。在试验 2 中，用 ESBM 代替 0%（鱼粉对照；ESBM0）、12.5%（ESBM12.5）、25.0%（ESBM25）、37.5%（ESBM37.5）和 50.0%（ESBM50）配制五种实验日粮的鱼粉。钩鱼(6.87 ± 0.02 g) 随机存放在 100 升圆柱形塑料罐中，每天喂食三次，持续 56 天。饲喂试验后，ESBM50组的WGR、FI、SGR、FER、PER和肌肉粗蛋白含量较对照组显着降低，ESBM50组的FCR显着升高。同时，肝胰腺和肠道蛋白酶活性以及肝胰腺超氧化物歧化酶、溶菌酶、天冬氨酸氨基转移酶和丙氨酸氨基转移酶活性随着日粮 ESBM 水平的增加而降低，并且 ESBM50 组与对照组有显着差异。提供 ESBM37.5 和 ESBM50 饮食导致肠粘膜皱襞萎缩和破裂以及上皮粘膜与固有层分离。这些结果表明 SBM 可以替代 12。R. lagowskii饮食，而 ESBM 可以替代 25% 的鱼粉。