# Moult-Induced Changes in Gut Microbiota of African Penguins (Spheniscus demersus)

## TL;DR

African penguins experience significant changes in gut bacteria during moulting, which may affect their health and conservation strategies.

## Contribution

This study reveals how moulting alters gut microbiota in African penguins, identifying vulnerable periods and potential health risks.

## Key findings

- Moulting significantly changes gut microbiota diversity and composition in African penguins.
- Mid- and post-moulting periods show increased harmful bacteria and decreased beneficial ones.
- Functional analysis shows reduced vitamin E biosynthesis and protein glycosylation during moulting.

## Abstract

African penguins (Spheniscus demersus) are critically endangered seabirds that go through a stressful annual moulting period. This study investigated how the microbial structure in their gut changes before, during, and after moulting, as these microbes are vital for health and digestion. The results of high-throughput sequencing showed that moulting significantly changed the diversity and composition of gut microbiota. Before moulting, penguins had more beneficial bacteria, but during and after moulting, the abundances of potentially harmful bacteria increased, making their gut environment more vulnerable. The findings suggest that African penguins are at higher health risk in the mid- and post-moulting stages. This information is helpful for improving the ex situ conservation strategies of seabirds by recommending strategies like reducing stress, allowing natural fasting, and considering nutritional support during moult.

The gut microbiota of seabirds can undergo shifts during the moulting period due to fasting. Understanding the characteristics of gut microbiota in African penguins (Spheniscus demersus) throughout moulting is meaningful for the conservation and management of this critically endangered seabird species. A total of 12 captive African penguins reared in Shanghai Zoo were divided into three sampling stages: (1) pre-moulting (Pre); (2) mid-moulting (Mid); and (3) post-moulting (Post). The 16S rDNA gene sequencing of faecal samples was performed to evaluate differences in diversity, composition, and predicted function of the gut microbiota across the moulting period. The results showed that Firmicutes, Proteobacteria, and Actinobacteria were the predominant bacterial phyla in African penguins throughout moulting. Moulting significantly altered the diversity and composition of gut microbiota in captive African penguins. Pre-moulting penguins exhibited higher abundances of Bacilli and Lactobacillales compared with mid- and post-moulting groups, whereas mid- and post-moulting penguins had increased abundances of several potentially harmful bacteria. In addition, the functional prediction analysis indicated that pre-moulting penguins had a higher abundance of protein N-glycosylation pathway compared with both mid- and post-moulting penguins. The pre-moulting group also exhibited a decreased abundance of the vitamin E biosynthesis pathway compared with the mid-moulting group. The present study has revealed that the gut environment of African penguins is more vulnerable during the mid- and post-moulting periods. The findings provide reference information for improving the management of endangered seabird species during moult.