Dietary yeast hydrolysate improves growth performance, antioxidant capacity, immunity, and intestinal microbiota of juvenile giant freshwater prawn (Macrobrachium rosenbergii)

Abstract

The present study investigated the influence of dietary yeast hydrolysate on growth performance, antioxidant capacity, immunity, and intestinal flora of juvenile giant freshwater prawn (Macrobrachium rosenbergii). Five experimental diets were formulated by incorporating 0%, 0.5%, 1%, 2% and 4% of yeast hydrolysate into the basal diet hereafter referred to as YH₀, YH_0.5, YH₁, YH₂ and YH₄, respectively. The diets were administered to 50 juvenile M. rosenbergii with an initial weight of 0.0451 ± 0.003 g in triplicates for eight weeks. The findings revealed that the prawns fed on YH_0.5 and YH₁ diets increased significantly weight gain and specific growth rate. The prawns fed on the YH₁ and YH₂ diets had significantly higher superoxide dismutase and glutathione peroxidase activities in the hepatopancreas, while decreased malondialdehyde content. Moreover, the prawns fed on the YH₁, YH₂ and YH₄ diets elevated significantly alkaline phosphatase and acid phosphatase activities in the serum. Furthermore, the prawns fed on the YH₁ and YH₂ diets had significantly higher total nitric oxide synthase activity and nitric oxide content, but had lower aspartate aminotransferase and alanine aminotransferase activities in the serum. The prawns fed on YH₀, YH₁ and YH₄ diets were analyzed to explore the changes in intestinal microbiota. The prawns fed on the YH₄ diet had significantly higher Shannon and Chao indices than those fed on YH₁ diet. Feeding the prawns on the YH₀ diet increased significantly Bacteroidetes phylum relative abundance than those fed on the YH₁ and YH₄ diets. Moreover, the prawns reared on YH₀ and YH₄ diets had significantly higher Saccharibacteria phylum relative abundance compared to those fed on the YH₁ diet. Flavobacterium, Lactococcus, Enterobacter and Lysobacter spp. were the dominant taxa in the gut microbiota across all treatments, with Flavobacterium sp. being the most abundant genus in the prawns fed on the YH₀ diet. The amount of dietary yeast hydrolysate required for optimum growth performance, antioxidant capacity and immunity in M. rosenbergii ranged from 0.9% to 2.6%. Collectively, these findings suggest that, moderate dietary yeast hydrolysate supplementation exerts improves growth performance, antioxidant capacity, and immunity in M. rosenbergii. Furthermore, dietary yeast hydrolysate modulates intestinal microbiota composition.