Correlation between intestinal microbiota composition and growth performance in largemouth bass (Micropterus salmoides)

This study aimed to explore the potential correlation between intestinal microbiota and growth performance of largemouth bass (Micropterus salmoides) following a 90-day feeding trial. Based on the final body weight (FBW), 396 fish were divided into four groups: the slow growing (FG) group (FBW: 100–150 g), slow-medium growing (SMG) group (FBW: 150–200 g), fast-medium (FMG) group (FBW: 200–250 g), and fast growing (FG) group (FBW: 250–300 g). Subsequently, the intestinal microbiota of the fish were analyzed. The sequencing results indicated that the genera Cetobacterium, Mycoplasma, and Mycobacterium were predominant, though their abundance varied significantly across the four groups. Furthermore, PICRUSt2 functional prediction analysis indicated that the FG group displayed a significant enrichment of genes associated with amino acid biosynthesis compared to that of the SG group. Finally, redundancy analysis demonstrated a significant positive correlation between intestinal Mycoplasma content and growth performance, suggesting that Mycoplasma may be a key microbe influencing the growth of largemouth bass. Nevertheless, the mechanism by which Mycoplasma affects the growth performance requires further investigation.