The Time Reliable Effect of Probiotic Clostridium butyricum on the Growth of Spotted Sea Bass (Lateolabrax maculatus).

Probiotic Clostridium butyricum has been demonstrated to enhance the growth of spotted sea bass (Lateolabrax maculatus). However, the time reliable effect of C. butyricum application for L. maculatus growth promotion is poorly understood, limiting our ability to make informed decisions about when the C. butyricum should be added and why. To address this, we employed multidisciplinary approach to investigate the growth response (including growth performance, intestinal morphology, digestive enzyme activities, and gut microbiome) of L. maculatus to C. butyricum supplementation throughout the entire breeding cycle (from juvenile to marketable size). The C. butyricum supplementation significantly increased the weight of L. maculatus during its early life stages. Correspondingly, 16S rRNA sequence showed that C. butyricum addition increased probiotic bacteria (including Lactobacillales), decreased pathogenic bacteria (including Enterobacterales, Burkholderiales, and Fusobacteriales), and reduced bacterial virulence processes (including quorum sensing, biofilm formation, and bacterial secretion systems) of gut microbiota in L. maculatus. Concurrently, C. butyricum supplementation increased intestinal villus height (up to 32.1%), muscle thickness (up to 115.8%), and digestive enzyme activities (up to 77.8%). Nevertheless, during the later stages of incubation, treatment with C. butyricum did not result in further improvements or even showed similar outcomes to the non-supplemented treatment. These findings emphasize that C. butyricum supplementation during the early breeding stage can significantly benefit L. maculatus growth, rather than adding it during later stages. This study provides evidence on the appropriate timing for C. butyricum supplementation in L. maculatus culture, offering timely information and technical support for its culture management.