Overall evaluation of the replacement of fermented soybean to fish meal in juvenile white shrimp, Litopenaeus vannamei diet: growth, health status, and hepatopancreas histomorphology

This study was conducted to determine the effect of replacing fishmeal (FM) with fermented soybean meal (FSBM) for 12 weeks on the growth performance, feed utilization, immunological parameters, antioxidant enzyme assays and lipid peroxidation, digestive enzymes, and histopathological analysis of juvenile Litopenaeus vannamei (L. vannamei). By substituting 0.0%, 20%, 30%, and 40% FSBM for fishmeal (w/w), four isonitrogenous diets were generated. A total of 300 juvenile L. vannamei (1.59 +/- 0.01 g) were randomly allocated to the experimental fiber tanks at a rate of fifteen shrimp per tank, with three replicates for each treatment. Growth performance and feed utilization decline considerably (P < 0.05) with increasing amounts of FM replacement with FSBM in diets. In comparison to the juveniles fed the other experimental diets, the diet containing a moderate level of FM replacement (20% FSBM) considerably enhanced growth performance and feed consumption during the feeding trial. The 20% FSBMfed group had the highest protein content. In contrast, raising FSBM levels significantly increased lipid content (P < 0.05) compared to the control. However, there were no statistically significant differences (P > 0.05) across FSBM treatments. Hemolymph plasma total protein (TP) concentration and lysozyme activity were substantially greater (P < 0.05) in 20% FSBM compared to 40% FSBM (P < 0.05). In addition, 20% FSBM exhibits a substantial (P < 0.05) increase in the activity of antioxidant enzymes (CAT SOD, GPX, and GR). In contrast, the control and 30% FSBM groups had considerably more lipid peroxidation markers (MDA) than the 20% and 40% FSBM groups. Hepatopancreas amylase activity was considerably elevated (P < 0.05) in the control group and with 40% FSBM. In addition, hepatopancreas and intestinal protease and lipase activity increased significantly by 20% FSBM. Considerably, more B cells were present in the 40% FSBM diet than in the control diet; however, they were significantly less prevalent in the 20% and 30% FSBM diets (P < 0.05).