Combined Addition of Microalgae and Probiotic Enhances Bacterial Community Network Stability, Water Quality, and Fish Growth in Micropterus salmoides Aquaculture

CFU/L), their combined addition, and a control. Our results indicated that the combined addition significantly improved fish growth performance and reduced total and inorganic nitrogen concentrations than single additions. Moreover, the combined addition enhanced nitrogen- and carbon-related metabolic functions in FL fraction and increased host-associated functions in PA community. Taxa assigned with the classes Bacilli, Bacteroidia, Gammaproteobacteria, and Alphaproteobacteria showed predominant explanations for variations in nitrogen and phosphorus. Furthermore, the combined addition enhanced potential interactions among taxa across lifestyles and strengthened the bacterial community network complexity and stability. These findings provide new insights into the microbial mechanisms underlying microalgae-probiotic synergism and offer a scientific basis for sustainable microbial management in freshwater aquaculture.