Intestinal bacterial community composition of juvenile Chinese mitten crab Eriocheir sinensis under different feeding times in lab conditions.

Feeding time is an important factor affecting the physiological activity and feeding rhythm of crustaceans. However, little is known about the factors and mechanisms contributing to variations in feeding time in aquatic species or their impacts. Moreover, the gut microbiome largely affects host physiology and is associated with diet. To investigate the effects of different feeding times on the composition of intestinal bacterial communities, high-throughput 16S rRNA sequencing was used to monitor the gut bacteria of the Chinese mitten crab Eriocheir sinensis over a 10-day period under different feeding times: 06:00 h, 12:00 h, 18:00 h, and 24:00 h. Weight gain of the day-fed groups was significantly higher than that of the night-fed groups. Two probiotics, Akkermansia muciniphila and Faecalibacterium prausnitzii, were detected in the intestines of crabs in the 12:00 group. In addition, the diversity and richness of the flora in the 12:00 group were slightly higher than those in the other treatment groups. These results collectively indicate that different feeding times change the intestinal flora composition of Chinese mitten crabs, and further identified specific feeding times associated with a more significant weight gain effect. Our findings provide important insights into improving farming strategies for Chinese mitten crabs.