Maternal programming of piglet microbiomes

Abstract

Understanding how maternal factors in early life influence piglet microbiomes is key to unlocking the potential for manipulation of these factors to positively influence pig health and production without the need to resort to individualized interventions such as dietary antimicrobials later in life. The objective of this thesis was to investigate the manipulation of several different maternal factors in swine production systems in early life and their influence on the development of piglet microbiomes and immunity. The first study involved the manipulation of sanitation levels in the maternal farrowing environment and their effects on piglet gut and nasal microbiome colonization and assembly. Disinfection was associated with decreased microbial exposures at birth, decreased microbial diversity in piglet gut and nasal microbiomes at birth, and altered microbiome assembly patterns from birth to weaning. The second study investigated the effects of maternal parity on sow and offspring microbiomes at weaning, as well as the effects of potential interactions between maternal parity and a dietary prebiotic on gut microbiomes of nursery pigs. The gut microbiomes of primiparous mothers and offspring displayed greater microbial diversity and altered composition at weaning when compared to multiparous animals. The effects of maternal parity lasted throughout the post-weaning period, with effects exacerbated for pigs fed a dietary prebiotic in the form of Aspergillus oryzae. Lastly, the third study investigated the effects of manipulation of maternal diet during late gestation and lactation through supplementation with a live yeast (Saccharomyces cerevisiae) feed additive on the development of piglet microbiomes and immunity. Live yeast supplementation at an inclusion rate of 0.1% was associated with reduced abundances of potentially pathogenic bacteria in sow colostrum and piglet gut microbiomes at weaning, as well as altered microbiome composition from birth to weaning. Overall, these studies provide evidence that maternal delivery environment, reproductive history, and diet can all influence the microorganisms colonizing piglet microbiomes at birth and in early life. Additionally, these studies indicate maternal characteristics inherent to the sow are a major driver of piglet microbiome assembly and development, with lasting implications for piglet microbiome composition and physiology.