Synergistic effects of a brown macroalgae premix extract and Bacillus subtilis on growth performance, haemolymph characteristics, antioxidant responses, and disease resistance in whiteleg shrimp (Litopenaeus vannamei)

The use of functional feed additives is a key strategy for improving growth performance, health status, and disease resistance in shrimp aquaculture. This study evaluated the effects of a brown macroalgae premix extract (MPE), composed of Sargassum ilicifolium, Nizimuddinia zanardini, Padina australis, and Cystoseira indica, in combination with the probiotic Bacillus subtilis (P), on growth performance, haemolymph chemistry, antioxidant capacity, and resistance to Vibrio parahaemolyticus in whiteleg shrimp (Litopenaeus vannamei). A total of ۲,۴۰۰ post-larvae (initial weight: ۱.۲۹ ± ۰.۲۸ mg) were randomly assigned to eight dietary treatments, including a control, MPE alone, probiotic alone at three inclusion levels, and combinations of MPE with each probiotic level, for ۶۰ days. Shrimp fed the MPE+P۲ and MPE+P۳ diets showed significantly higher final weight, weight gain, and specific growth rate than the control and other treatments (p < ۰.۰۵). These groups also exhibited significantly elevated total haemocyte counts, while the MPE+P۲ treatment resulted in the highest haemolymph protein level and the lowest glucose concentration (p < ۰.۰۵). Combined supplementation significantly enhanced superoxide dismutase and glutathione peroxidase activities and improved post-challenge survival against V. parahaemolyticus, with the highest survival rate observed in the MPE+P۲ group. Overall, dietary supplementation with brown macroalgae extracts in combination with B. subtilis exerted synergistic effects on growth performance, immune-related haemolymph parameters, antioxidant status, and disease resistance in L. vannamei.

کلیدواژه ها:

Brown macroalgae extract ، Bacillus subtilis ، Litopenaeus vannamei ، Growth performance ، Haemolymph parameters ، Antioxidant enzymes ، Disease resistance