Effects of Dietary Supplement of Probiotic on Intestinal Microbiota and Barrier Structure, Immune Function, and Antioxidant Capacity of Soft-Shelled Turtle .

inhabits animal gastrointestinal tracts and has been demonstrated to benefit livestock and poultry, but its effects on soft-shelled turtles remain unexplored. The present work investigates the effects of probiotic on intestinal microbiota and barrier structure, immune function, and antioxidant capacity of the soft-shelled turtle. Twenty-four juvenile were divided into two groups: control (fed a basal diet) and treatment (fed a diet supplemented with , 3.3 × 10 CFU/g feed), over a period of 6 weeks. We found that did not promote the growth of turtles at the present feeding level, but the treatment resulted in significant alterations in the intestinal microbial community structure, with increased abundance of , , and , and a reduction in (  < 0.05). notably enhanced villus height/crypt depth, villus width, and villus density in the intestine. The treatment group exhibited a 1.50-fold increase in goblet cells count and a 1.18-fold higher in the muscular layer thickness compared to the control group. also improved the immune function, with an increase in the ratio of plasma neutrophils and lymphocytes to the total number of leukocytes after feeding probiotics, and upregulation of the levels of toll-like receptor 4 (TLR 4), lysozyme, interleukin 1 (IL-1), tumor necrosis factor (TNF-), and immunoglobulin A (IgA) in the intestine, as well as the level of hepatic immunoglobulin M (IgM). Additionally, supplementation boosted antioxidant capabilities, including a significant increase in catalase (CAT) and glutathione peroxidase (GPx) activity and reduced glutathione (GSH) levels in the intestine and GSH levels in the spleen. Our study demonstrates the beneficial effects of supplemental on the intestine and overall health of soft-shelled turtles, particularly in enhancing their immune function and antioxidant capacity.