Marine microbes suppressed Vibrio and enhanced biological performance of euryhaline rotifer, Brachionus plicatilis

The excessive use of antibiotics in mariculture has surpassed permitted levels, leading to their release into surrounding waters and accumulation in cultured organisms, which poses risks to human health and highlighting the urgent need for alternatives to reduce antibiotic use. Therefore, the present study aimed to test four microbes including Debaryomyces hansenii, Ruegeria mobilis, Lactobacillus plantarum and Bacillus subtilis, on lowering Vibrio, promoting population increase and survival of Brachionus plicatilis. The digestive enzymes activity including α-amylase, lipase and protease, microbial retention and biochemical composition of rotifers were analyzed. Rotifers with a density of 50 ind/mL were distributed into five treatments (four experimental and a control, quadruplicate, repeated thrice). Each microbe's concentration of 10⁸CFU/mL^-1 was applied to the culture condition. L. plantarum and B. subtilis decreased Vibrio and increased the population and survival of rotifers, due to successful colonization, resulting in better nutritional utilization and retention in these groups. Higher enzymatic activity and microbial retention were observed in B. subtilis group. The present findings demonstrate that L. plantarum and B. subtilis could be promising microbes for culture of B. plicatilis to lower Vibrio and ensure higher yields. Identifying a sustainable approach to inhibit Vibrio while enhancing rotifers' performance as the primary food source for marine larviculture is undoubtedly essential.