New insights into canine milk: a multi-omics approach

Abstract Background A mother’s milk is considered the gold standard of nutrition in neonates and is a source of cytokines, immunoglobulins, growth factors, and other important components, yet little is known about the components of canine milk, specifically colostrum, and the knowledge related to its microbial and metabolic profiles is particularly underwhelming. In this study we characterized canine colostrum and milk microbiota and metabolome of several breeds of dogs and examined profile shifts as milk matures in the first 8 days post-whelping. Results Through untargeted metabolomics, we identified 63 named metabolites that were significantly differentially expressed between days 1 and 8 of lactation, whereas the microbial compositions of the colostrum and milk, characterized using 16S rRNA gene sequencing, were, surprisingly, largely similar, with only two differentiating genera. The shifts observed, mainly increases in several sugars and amino sugars over time and shifts in amino acid metabolites, align with shifts observed in human milk samples and track with puppy development. Conclusion Like human milk, canine milk composition is dynamic, and shifts are well correlated with developing puppies’ needs. Such a study of the metabolic profile of canine milk, and its relation to the microbial community, provides insights into the changing needs of the neonate, as well as the ideal profile for optimal functionality. This information will add to the existing knowledge base of canine milk composition with the prospect of creating a quality, tailored milk substitute or supplement for puppies.