The Role of Semi-Wild Habitats in the Physical Conditions of Juvenile Alligators: Implications for Conservation.

The number and survival rate of juveniles play a key role in the recovery of Chinese alligators (Alligator sinensis). The differences between artificial and semi-wild environments can directly affect the growth and development of juvenile alligators. This study analyzed the physical conditions (lengths and weights) and cloacal microbial communities of juvenile alligators in both artificial breeding (DJ, ZX) and semi-wild (GJM) environments to reveal the significant effects of environmental pressure on their physiological state and microbiome. The results revealed that the body length (23.15 ± 1.06 cm) and weight (22.8 ± 3.08 g) of juvenile alligators in the GJM were significantly lower than those in the artificial environment (body length = 29.5 cm, weight = 68.6 g; p < 0.01). Moreover, the microbial α diversity (ACE, Shannon) of the GJM was significantly reduced, and the community structure was significantly separated (NMDS analysis), suggesting that the pressure of the semi-wild environment inhibited growth. In terms of microbial composition, the relative abundance of Actinobacteria in the GJM group was significantly, increased, whereas that of Bacteroidetes was decreased, and Microbacteria and Cyanobacteria were unique; at the genus level, environmentally specific marker genera were identified (such as Limnohabitans and Pseudomonas in GJM and Fluviicola and Deinococcus in the artificial environments). LEfSe analysis further elucidated the differential marker microbiota (such as Actinobacteria/Cyanobacteria in GJM). In summary, stress (such as food shortages) in semi-wild environments affects the growth and development of juvenile alligators by changing their microbial communities (such as enriched actinomycetes), This finding provides a microbial ecological basis for optimizing the conservation strategy of the Chinese alligator.