Effects of Replacing Fishmeal by Raw or Lactobacillus acidophilus-Fermented Soybean Meal on Growth, Intestinal Digestive and Immune-Related Enzyme Activities, Morphology, and Microbiota in Turbot (Scophthalmus maximus L.)

This study was performed to investigate the fermentation efficiency of Lactobacillus acidophilus and compare effects dietary soybean meal (SM) or L. acidophilus-fermented SM (LASM) on turbot. Two hundred seventy juvenile turbots ( 13.50 ± 0.13 g ) were randomly divided into three treatments fed with a fishmeal-based diet (CNT) two experimental diets 45% fishmeal protein replaced by LASM for 8 weeks. The results showed that significantly improved essential amino acid profile, increased lactic content, reduced antinutritional factor level in SM. Inferior growth fish observed group after feeding trial, while exhibited comparable performance CNT group. Activities intestinal digestive enzymes (trypsin diastase) immune-related (alkaline phosphatase, lysozyme) decreased group, no significant reduction found compared Dietary alleviated SM-induced pathological disruption higher villus normal lamina propria width. positively regulated microbiota, making overall profile more coherent Spearman’s correlation analysis revealed altered microbiota closely linked enzyme activities. Collectively, this indicated nutritional quality relieved adverse turbot, terms growth, activities, morphology, microbiota.