Gut microbiota is closely associated with the development of the host. The microorganisms that survive within the gastrointestinal tract were actively selected by the host. The gut microbiota also has great effects on its hosts (e.g. the maintenance of homeostasis, activation of immune system). Interactions between the gut microbiota and host have been a hot topic in the field of gut microbiota.

By using the high through-put sequencing approaches, scientists from the Research Group of Taxonomy and Ecology of Protozoa at Institute of Hydrobiology (IHB) of Chinese Academy of Sciences studied the temporal variations of gut microbial community of gibel carp (Carassius auratus gibelio), one of the key freshwater aquaculture fish species in China. 

They found that the gut microbial diversity increased significantly once host hatched (after three days post-hatching). The clustering analysis revealed a “stage-specific” succession of the gut microbial communities that resolved three discrete clusters, 3–33, 38–51, and 58–365 DPH (days post-hatching). However, this “stage-specific” pattern in the gut microbial succession was not significantly correlated with the developmental stages of the host. 

By using the net relatedness index (NRI) to analyze the ecological process during the succession of microbial community, scientists found that selective pressures from the host drive the assembly of gut microbiota. However, the influence of the host-associated deterministic processes tends to weaken over with the gibel carp development.

These findings shed new light on further studies of the fish gut microbial community composition and function. This study was published in Microbial Ecology, and was supported by the National Natural Science Foundation of China.