Regulatory Effects of Probiotic Complex Formulations on Gut Health of Litopenaeus vannamei and Steady-State of Aquaculture Environment

Abstract

This study assessed three probiotic complexes (PCF1: Bacillus subtilis + Lactobacillus plantarum; PCF2: B. subtilis + Saccharomyces cerevisiae; PCF3: L. plantarum + S. cerevisiae) on Litopenaeus vannamei gut health and intensive aquaculture environment stability over 12 weeks. Four groups (control + PCF-supplemented diets: 1×10⁸ CFU/g) were tested in quadruplicate (300 shrimp/tank, initial weight 0.72±0.06 g). PCF1 showed the most significant effects: gut villus height (+42.3%), epithelial thickness (+35.6%), and digestive enzyme activities (amylase/protease/lipase +38.7%/+45.2%/+32.6% vs. control, P<0.05). It reduced total ammonia nitrogen (52.7%), nitrite nitrogen (58.3%), and COD (36.9%) (P<0.05), enriched gut beneficial bacteria (Lactobacillus, Bacillus), decreased Vibrio, and enhanced water nutrient-degrading microbes. PCF1 also improved shrimp survival (94.2±2.3%) and weight gain (356.8±18.5%) (P<0.05). This study confirms PCF1 as an effective formulation for promoting shrimp gut health and maintaining aquaculture environment steady-state, supporting sustainable intensive shrimp culture.