Abstract
To study the differences in morphological characteristics, muscle nutrition, and intestinal microbiota of largemouth bass under different farming modes, healthy largemouth bass with an initial body weight of 50.0 (± 2.0) g were selected and reared for 180 d under traditional pond farming (Group A), flow-through farming (Group B), and high-position pond farming (Group C) modes. The results showed that: (1) the condition factor, hepatosomatic index, and visceral somatic index of largemouth bass in Group B were significantly higher than those in Group C (P < 0.05); (2) the crude fat content in muscle of fish in Group B was significantly lower than that in Group A (P < 0.05). However, the crude protein content was significantly higher than that in Group A (P < 0.05). The total amino acid content, total non-essential amino acids, total umami amino acids, and total aromatic amino acids in muscle of fish in Group B were significantly higher than those in Groups A and C (P < 0.05). The monounsaturated fatty acids, polyunsaturated fatty acids, and DHA + EPA contents in muscle of fish in Group B were significantly higher than those in Group A (P < 0.05) and extremely significantly higher than those in Group C (P < 0.01), and; (3) alpha diversity analysis showed that the intestinal microbiota diversity of largemouth bass in Group B was higher than that of the other two groups. At the phylum level, the dominant bacterial phyla in largemouth bass intestines were Fusobacteriota, Firmicutes, Proteobacteria, Bacteroidota, and Actinobacteria. At the genus level, the dominant bacterial genera were Mycoplasma, Cetobacterium, and Acinetobacter. Principal coordinate analysis based on operational taxonomic units indicated that the microbiota distribution of Group B differed slightly from that of Group A and differed significantly from that of Group C. This indicated that the species diversity of the intestinal microbiota of largemouth bass varied under different farming modes. In conclusion, the farming mode affected the growth, muscle nutritional quality, and intestinal microbiota of largemouth bass. This study provides a theoretical basis for understanding the relationships between farming modes, growth performance, muscle nutrition, and intestinal microbiota in largemouth bass.