Dietary impact of shrimp diets containing a mixture of nucleotides, β ‐glucan, and mannan oligosaccharides on the growth performance, innate immunity, gene expression, and histology

This experiment investigated the impact of Hilyses, a fermented Saccharomyces cerevisiae ‐based supplement containing bioactive nucleotides, β‐glucans, and mannan oligosaccharides (MOS), on the performance and physiology of whiteleg shrimp, Litopenaeus vannamei (initial weight 4.47 ± 0.07 g). Shrimp were fed diets with 0, 0.30, or 0.50 g/kg Hilyses for 60 days. Growth rate and feed utilization improved significantly with increasing Hilyses inclusion. Dietary Hilyses at 0.30 and 0.50 g/kg enhanced total and differential hemocyte counts, phagocytic and respiratory burst activities, and lysozyme, acid, and alkaline phosphatase (ALP) enzyme levels. Antioxidant enzymes, including catalase, glutathione, and superoxide dismutase, were markedly enhanced, while lipid peroxidation declined across the hepatopancreas, gills, and intestines of shrimp fed 0.30 and 0.50 g/kg Hilyses. Prophenoloxidase , penaeidin‐3 , and hemocyanin gene expression increased following supplementation at both doses. Histological analysis revealed normal gills and hepatopancreas structures with abundant blister (B) cells, indicating that Hilyses supplementation at 0.30 and 0.50 g/kg may promote the conversion of fibrillar (F) cells to B cells, improving intracellular digestion and nutrient absorption, and enhancing shrimp growth. Collectively, Hilyses at 0.30–0.50 g/kg enhanced antioxidant and immune functions and supported healthier tissue morphology, demonstrating its value as a functional dietary additive for L. vannamei culture.