Size-dependent effects of the intestinal microbiota in juvenile Chinese alligators: implications for species protection.

Increasing the quality of offspring to optimize population reproductive efficiency represents a viable approach for increasing population size. The population of Chinese alligators has a growing age structure, but the high mortality rate of juveniles is a serious problem that needs to be solved. We investigated the relationship between the weight of juvenile Chinese alligators and the microbiota to improve the survival rate and provide better protection for Chinese alligators. The results revealed significant differences in body weight among the selected individuals. Among the 35 most abundant microbial genera in the different weight groups, four genera (Stenoxybacter, Gracilibacteria, Absconditabacteriales_(SR1) and Saccharimonadales) were significantly positively correlated with weight. These genera can help the host shape the anaerobic environment of the intestine, degrade organic acids and proteins, and promote the production of growth-promoting factors. This study provided valuable insights into the relationship between the microbiota and weight, along with theoretical guidance for improving the survival rate of juvenile Chinese alligators.