Gut and milk-associated microbiota

Microorganisms living in the gut are necessary for maintaining homeostasis. Microorganisms colonize the gut during early life, help with developing mucosal immunity, establish a population that inhibits growth of pathogens, and in humans, they synthesize vitamins B and K. Our diets have huge impacts on which microorganisms are present in the gut and in turn, those microorganisms can be beneficial or detrimental to our metabolism. In mammals, gut microorganisms are somehow transferred to the mammary glands and live within the milk and suspected to be transferred to offspring and colonize the offspring gut along with maternal antibodies. Milk is a powerful part of mammalian evolution and its quality is highly dependent on maternal diet and condition.

For my master’s work I conducted with Dr. Wendy Hood at Auburn University, I examined how dietary protein intake impacted milk microorganisms and fecal microbiota of lactating rats, and cecal microbiota of the rat dams and her pups (Warren et al. 2019). We determined that the bacterial community in milk is different than what was in the gut of the mother and her pups which suggest that the milk microbiota includes microbes from the teat skin or offspring’s mouth.

Adapted Figure 2 from Warren et al. 2019. Dam milk contains a bacterial community that is compositionally different than the dam’s and pup’s cecum. Dams were fed either a high-protein (20%) or low-protein (10%) diet. Samples were clustered using Bray-Curtis and the stress of the plot was 0.07.