Differences in the fecal microbiota due to the sexual niche segregation of captive Gentoo penguins Pygoscelis papua

The Gentoo penguin (Pygoscelis papua) is the most abundant penguin species in Antarctica and the sub-Antarctic islands due to its generalist foraging ecology. Previous studies indicate that the broad diet in Gentoo penguins mainly result from sexual niche segregation caused by its foraging ecology. However, differences in food metabolism and absorption between Gentoo penguins of different genders has been ignored. Gut microbiota of animals plays a vital role in the digestion, absorption, and metabolism of nutrients from diets. Here, captive Gentoo penguins were used to reveal the sexual niche segregation of gut microbiota. The results showed that both the composition and function of gut microbiota composition between male and female Gentoo penguins were significantly distinct. Moreover, a higher degree of individual differences in gut microbiota were found in female Gentoo penguins than in males and a greater impact of sexual maturity on gut microbiota was also observed in females. The family of Lachnospiraceae and C5-branched dibasic acid metabolism were more abundant in the gut microbiota of male Gentoo penguins, indicating a higher carbohydrate metabolic capacity in males. In contrast, Fusobacteriaceae and the D-alanine pathway were enriched in females, suggesting that female Gentoo penguins have a greater capacity to metabolize proteins. Because the captive Gentoo penguins were living in the same environment and feeding on consistent diets, the gender-related differences in gut microbiota observed in the present study could be a genetic characteristic of this species.