Effects of heat-inactivated Lactobacillus acidophilus AC on growth performance and intestinal health of Larimichthys crocea

Abstract

The overuse of antibiotics in aquaculture presents significant challenges, including the emergence of drug-resistant pathogens, environmental contamination, and food safety risks. Probiotics have emerged as a promising alternative, with heat-inactivated probiotics gaining prominence for their enhanced safety and stability. This study investigates the effects of heat-inactivated Lactobacillus acidophilus AC on the growth performance and intestinal health of juvenile yellow croaker, Larimichthys crocea . Heat-inactivated L. acidophilus AC was prepared at two concentrations—1×10 ¹⁰ CFU/g (ABI1 group) and 1×10 ¹¹ CFU/g (ABI2 group)—and incorporated into the basal diet. These were compared to a control group (NC group) in a 56-day feeding trial. The results demonstrated that the intestinal morphology was significantly improved ( P < 0.001). The diversity of the intestinal microbiota community in the ABI2 group showed a decreasing trend ( P < 0.05). Furthermore, the intestinal metabolism was significantly influenced by heat-inactivated L. acidophilus AC. In summary, heat-inactivated L. acidophilus AC has been demonstrated to optimize growth by optimizing the structure of the intestinal microbiota and promoting the production of beneficial metabolites. This study provides a scientific basis for the application of heat-inactivated probiotics in aquaculture.