Study of fermented feed by mixed strains and their effects on the survival, growth, digestive enzyme activity and intestinal flora of Penaeus vannamei

Abstract

Abstract In this study, the mixed strains, including Lactobacillus plantarum (STBL1), Saccharomyces cerevisiae (STBS1), and Bacillus safensis (SQVG18) were applied to the solid-state fermentation of commercial feed for Penaeus vannamei. Firstly, the optimum combination of strain inoculum, optimum fermentation conditions, and nutritional quality of the fermented feeds were investigated. It was noted that the acid-soluble protein and the content of amino acids (lysine, methionine, etc.) were remarkably improved in the feeds by solid-state fermentation with the optimum combination of STBL1: STBS1: SQVG18\xa0=\xa01: 3: 3. Secondly, a six-week feeding experiment was performed using one control diet without probiotics (D0: 0\xa0CFU\xa0g−1) and three fermented diets containing different concentrations of the optimum mixed-strain combination (D1: 107\xa0CFU\xa0g−1; D2: 108\xa0CFU\xa0g−1; D3: 109\xa0CFU\xa0g−1). Shrimps fed D2, and D3 groups exhibited significantly better growth performance and activities of antioxidant enzymes and digestive enzymes than shrimp of other groups (P