Effects of replacing fishmeal with dietary wheat gluten meal (WGM) on growth, serum biochemical indices, and antioxidative functions, gut microbiota, histology and disease resistance for juvenile shrimp Litopenaeus vannamei

Abstract

The effect of replacing FM with WGM was assessed when shrimp were fed with varying WGM levels in total diets (TD) at W0 (0%), W2 (2%), W4 (4%), W6 (6%), W8 (8%), W12 (12%), and W16 (16%) on the growth, proximate body composition, serum biochemical indices and antioxidant activities, histology, gut microbiota and disease resistance in juvenile Pacific whiteleg shrimp. Forty shrimp per tank was fed with their respective experimental feed for eight weeks with three replicates for each group. Average initial weight of the shrimp was (0.24 ± 0.00 g). The results from the present study showed that growth performance including weight gain, specific growth rate and feed conversion ratio, were affected among the treatment groups (P < 0.05). Proximate composition in shrimp such as crude protein, moisture, the ash content in the shrimp was also enhanced with the shrimp fed WGM diets but not significantly different from each other groups. Serum acid phosphatase and alkaline phosphatase were affected after shrimp were fed WGM diets (P < 0.05). Serum total antioxidant capacity (T-AOC) first enhanced and later decreased after shrimp were fed various levels of WGM diets. In the histological analysis, villus height and intestinal wall thickness in shrimp mid-gut were affected when FM was replaced with WGM in shrimp diets. Gut microbiota, the total number of valid reads ranged from 39,924 to 52,506. Beneficial bacteria including Proteobacteria dominated the gut bacterial community in the shrimp gut fed WGM diets at phylum level. Cumulative mortality was low when shrimp were fed with WGM diets, with W6 (6%) obtaining the lowest value of 62%. In summary, replacing FM with WGM at 6% in TD could cater for shrimp nutritional needs.