Dietary probiotic Aspergillus niger preparation improves the growth performance, health status, and gut microbiota of white shrimp, Penaeus vannamei

Aspergillus niger is a unique fungus with benefits that can help improve the performance of terrestrial and aquatic animals. However, studies on the use of A. niger on aquatic animal species are limited. The present study investigated the effects of A. niger preparation as a dietary supplement on growth, gut microbiota, and immune response of white shrimp, Penaeus vannamei. The experiment was conducted over a 56-day trial period, with shrimps fed a control diet, and three diets containing three doses of A. niger preparation 0.5, 1 and 1.5 g (kg diet)−1) designated as P500, P1000 and P1500, respectively. The results showed that increasing concentrations of A. niger preparation led to higher weight gain and final weight in shrimp. Moreover, increasing levels of A. niger preparation of P1000 and P1500 reduced the mortality rate of shrimp challenged with Vibrio parahaemolyticus. In A. niger groups, PA, RBs, PO and LYS activities of shrimp significantly increased compared to the control group. Microbial analysis revealed significantly higher Vibrio-like counts in the gut of shrimp fed the control diet than in all A. niger-supplemented diets. Shewanella belonging to the dominant phylum Proteobacteria was highly expressed in the microbiota of shrimp fed P1000 diet. Meanwhile, Vibrio was relatively abundant in the control group. Unique genera, such as JGI0000069P2 and Marinicella, promoted bioremediation activities, while Halobacteriovorax aided in the elimination of V. parahaemolyticus infection in shrimp. Notably, a symbiotic relationship between Shewanella and Halobacteriovorax bacteria in the gut jointly boosted the immune responses of shrimp in defense against V. parahaemolyticus infection. These findings suggest that the A. niger preparation, due to its beneficial effects, could potentially be included in the diet to promote growth and a healthy intestinal microbiota, while also serving as a prophylactic treatment and immunological booster for shrimp.