Indigenous Gram-Negative Bacteria as Probiotics for Pacific White Shrimp (Litopenaeus vannamei).

Probiotics have been demonstrated to enhance growth performance, immunity, and reproduction in aquaculture species. Probiotics are a strong candidate as new safe solution for antibacterial related antibiotic-resistant pathogenic bacteria. In this study, we conducted a 30-day feeding trial on 10 cfu/g of indigenous Gram-negative bacteria Shewanella algae A3 and Serratia marcescens Van80 UB3 as probiotics using post-larval shrimp at stage 10 (PL-10). The new isolate as a probiotic strain for shrimp aquaculture was establish for a safety profile of antibiotic resistance assessment using phenotypic and molecular approaches. The Pacific white shrimp (Litopenaeus vannamei) exhibited improved growth, enhanced digestive enzyme activities, normal histological structures, increased expression of growth-related genes, and improved immunity when fed diets containing either single or multi-indigenous probiotics. The multi-indigenous probiotic group (C) displayed significantly higher lipase, amylase, and protease activities (P < 0.01) compared to the other groups. Furthermore, growth performance in the multi-indigenous probiotic group (C) was significantly better than that in the single probiotic groups (P < 0.05). Additionally, the expression of growth-related genes, including IGF-1, ecdysteroid, and myosin in the intestines, hepatopancreas, and muscles, was significantly higher in group C (P < 0.05). These findings strongly suggest that enriching the diets of Pacific white shrimp with 10 cfu/g of multi-indigenous Gram-negative bacteria probiotics can significantly improve growth performance, immunity, contribute to sustainable shrimp farming practice, and reduce of antibiotics application in aquaculture.