Changes of gut microbiota diversity and stability over the reproduction process in captive female Gentoo penguins (Pygoscelis papua)

Homeostasis of gut microbiota is critical for growth and health of animals. However, the impact of reproduction on penguin gut microbiota remains unclear, despite penguins being sentinel species of the marine environment. Through high-throughput sequencing of 16S rRNA gene, we examined changes in gut microbiota structure and function in captive female Gentoo penguins during the reproductive process, and also assessed the community stability and assembly mechanism. We found that gut microbiota alpha diversity decreased significantly in captive female Gentoo penguins after egg laying. Based on the comparison of gut microbiota compositions and their predicted functions, the Fusobacteria and pathogenicity increased after laying eggs, while Bacteroidetes and carbohydrate metabolism decreased. After laying eggs, the diversity of the gut microbiota decreased continuously until chicks left the nest. The co-occurrence network analysis revealed that the gut microbiota of captive female Gentoo penguins was less complex and more stable after egg laying. On the basis of the null model, deterministic processes drove the gut microbiota assembly in gravid Gentoo penguins, whereas reproductive processes elevated the contribution of stochastic processes. Our study provides insights into the reproductive physiology and gut microbiota assembly in penguins.