Complex probiotics can reduce diarrhea by boosting immunity and balancing gut microbiota in weaned piglets.

Purpose: SOLVENS (SLV) is a zootechnical feed additive based on viable spores of and . This study aimed to evaluate the effects of SLV on the intestinal health of weaned piglets.

Methods: A total of 360 healthy 24-day-old weaned Duroc × Landrace × Yorkshire piglets were allocated to three treatment groups based on body weight and sex: T1 (Control, CON), T2 (SLV 200, 6.5×10 CFU per kg feed), and T3 (SLV 400, 1.3×10 CFU per kg feed). Each treatment consisted of 30 replicates with four pigs per replicate, and the experiment lasted 42 days. Piglets were fed mash pre-starter feed (days 1-14) and mash starter feed (days 15-42). Growth performance, fecal microorganisms, serum immunity, and intestinal barrier function were assessed. Experimental data were analyzed using SPSS 27.0 for one-way ANOVA, and multiple comparisons were made using the DUNCAN method.

Results: Compared with the control, SLV 200 and SLV 400 significantly reduced diarrhea rate ( < 0.05). SLV 200 increased fecal and decreased on day 14 ( < 0.05), while SLV 400 elevated on days 14 and 42 and reduced on day 14 ( < 0.05). SLV 200 increased fecal sIgA and serum IgG on day 42 ( < 0.05), whereas SLV 400 elevated serum IgG and IgM on day 14 ( < 0.05) and serum IgA on day 42 ( < 0.05). Additionally, SLV 200 downregulated ileal () and () gene expression ( < 0.05), and SLV 400 reduced expression ( < 0.05).

Conclusion: Dietary supplementation with SLV improved intestinal health by modulating gut microbiota and enhancing immunity in weaned piglets.