The gut microbiomes of Antarctic penguins are important for the fitness of the host birds and their chicks. The compositions of microbial communities in Antarctic penguin guts are strongly associated with the birds’ diet, physiological adaptation and phylogeny. Whilst seasonal changes in food resources, distribution and population parameters of Antarctic penguins have been well addressed, little research is available on the stability or variability of penguin stomach microbiomes over time. Here, we focused on two Pygoscelis penguin species breeding sympatrically in the maritime Antarctic and analysed their stomach contents to assess whether penguin gut microbiota differed over three austral summer breeding seasons. We used a high-throughput DNA sequencing approach to study bacterial diversity in stomach regurgitates of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins that have a similar foraging regime on Signy Island (South Orkney Islands). Our data revealed significant differences in bacterial alpha and beta diversity between the study seasons. We also identified bacterial genera that were significantly associated with specific breeding seasons, diet compositions, chick-rearing stages and sampling events. This study provides a baseline for establishing future monitoring of penguin gut microbiomes in a rapidly changing environment.

Bacteriophages and lipids in human milk may benefit preterm infant health by modulating gut microbiomes. Here, we present a protocol for analyzing the phageome and lipidome in preterm milk using shotgun metagenomics and untargeted lipidomics approaches, respectively. We describe steps for extracting phages and lipids in low-volume milk, characterizing phageome using an in-house bioinformatic pipeline, and statistical analysis to correlate the phageome and lipidome. Finally, we detail an in vitro assay to examine the associations between fatty acid chain length and phage morphotype. For complete details on the use and execution of this protocol, please refer to Yew et al.¹.