Microbiomic analysis reveals the intestinal microbiota characteristics of crayfish (Procambarus clarkii) in different sizes and its potential impact on growth

Intestinal microbiota is symbiotic with the host and play an important role in immune response, digestive physiology, and regulation of body functions. Besides, it is also well documented that the intestinal microbiota of aquatic animals was closely related to their growth rate. However, whether it results in the different sizes of crayfish in rice-crayfish co-culture model remains vague. Here, we analyzed the intestinal microbiota characteristics of crayfish in three different sizes in the same typical rice-crayfish co-culture field by 16S rDNA high-throughput sequencing and investigated the relationship between crayfish intestinal microbiota structure and the living water and soil sediments. The results showed that there were significant differences in the dominant intestinal microbiota of crayfish between the three different sizes (BS, NS, SS), including Bacteroides and Candidatus_Bacilloplasma, which were more abundant in BS. Correlation networks showed that differences in intestinal microbiota made more susceptible in SS to water and sediment, where BS was more stable. Function prediction indicated that Bacteroides and Candidatus_Bacilloplasma contribute to the growth of crayfish by facilitating food digestion through cellulolysis, producing some beneficial metabolites that can promote better digestion and absorption. This might be one of the potential factors affecting the difference in crayfish sizes. These findings revealed the intestinal microbiota characteristics of crayfish in different sizes and its potential impact on growth, which is valuable for managing and manipulating the crayfish intestinal microbiota to achieve high productivity in practice.