Effectiveness evaluation of five probiotics on shrimp and water environment

To solve the aquaculture farmers’ difficulty in choosing suitable probiotics, we evaluated the five-probiotics sold in the market. Here, Bacillus subtilis-based product, compound Bacillus-based product (BC), nitrifying bacteria-based product (NB), photosynthetic bacteria-based product (PB) and aquatic lactic acid bacteria-based product (AL) were sprayed into the aquaculture water for 42 days, and shrimp performance and the water environment were measured. The results showed that NB, PB, and AL significantly increased the shrimp growth performance (p < 0.05). The five probiotics enhanced AMS activity significantly (p < 0.01). BC, PB, and AL reduced MDA, GOT, and GPT activity, while BS increased the Vibrio resistance and SOD, CAT, GSH-PX activity. The 16 s sequencing analysis revealed that compared to the control group, the AL and PB groups had significantly different microbial compositions, fewer unique ASVs, and lower intestinal microbiota abundance. Prevotella_7, Muribaculaceae_unclassified, and Veillonella were negative correlation with growth performance significantly, and Enterobacter, Hafnia-Obesumbacterium, Pseudomonas, and Klebsiella were positive correlation with immunity index (p < 0.05). In the control group, 72 % of the gut microbiota originated from the culture water, and this proportion increased after probiotics were added. All five probiotics improved water quality, especially AL. These data suggested that different probiotics have distinct preferences. AL showed the best overall performance, including high growth, favorable gut microbiota, and improved water quality. BS played a key role in enhancing shrimp resistance to Vibrio and nonspecific immunity. This study helped improve the efficacy assessment of aquatic probiotics and provides a theoretical basis for selecting suitable probiotics.