Comparative analysis of muscle quality, intestinal morphology and microbial composition in two cultured frogs species

In order to investigate the muscle quality, intestinal morphology and microbial composition of Hoplobatrachus tigerinus and Lithobates catesbeiana, we monitored the muscle nutritional components of two cultured frogs species by national food safety standard measurement method, and evaluated their muscle quality in addition with analysis of muscle texture and microstructure. Besides, we applied high-throughput sequencing and histological section technology to analyze the microbial community composition and microstructure of their gut. The results show that there was no significant difference in the total amino acids between H. tigerinus and L. catesbeiana (P>0.05). The unsaturated fatty acids content of L. catesbeiana were significantly higher than those of H. tigerinus (P<0.05). In addition, the muscle hardness, chewiness and gumminess of L. catesbeiana were significantly higher than those of H. tigerinus (P<0.05). The analyses of intestinal microbial communities show that the Shannon, Ace and Chao1 indexes of H. tigerinus were significantly higher than those of L. catesbeiana (P<0.05). At phylum level, the abundance of Firmicutes in L. catesbeiana was significantly higher than that in H. tigerinus (P<0.05), while the abundance of Actinobacteriota was significantly lower (P<0.05); At genus level, the abundance of Lactococcus and Escherichia-Shigella in H. tigerinus was significantly higher than that in L. catesbeiana (P<0.05), while Lactobacillus and Leuconostoc were significantly lower (P<0.05). The results show that there are differences in muscle quality between H. tigerinus and L. catesbeiana, but both have high nutritional value; high-throughput sequencing analyses show that there are differences in the composition of intestinal microbial communities between the two species.