Weaning transition, but not the administration of probiotic candidate Kazachstania slooffiae, shaped the gastrointestinal bacterial and fungal communities in nursery piglets

Authors: HARLOW, KALYNN - US Department Of Agriculture (USDA); SUMMERS, KATIE LYNN - Former ARS Employee; Oliver, William; Wells, James - Jim; FERGUSON, MARTINE - Food And Drug Administration(FDA); Crouse, Matthew; Neville, Bryan; Rempel, Lea; Rivera-Colon, Israel; Ramsay, Timothy; Davies, Cary

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2023
Publication Date: 1/11/2024
Citation: Harlow, K., Summers, K., Oliver, W.T., Wells, J., Ferguson, M., Crouse, M.S., Neville, B.W., Rempel, L.A., Rivera-Colon, I., Ramsay, T.G., Davies, C.L. 2024. Weaning transition, but not the administration of probiotic candidate Kazachstania slooffiae, shaped the gastrointestinal bacterial and fungal communities in nursery piglets. Frontiers in Veterinary Science. 10. Article e1303984. https://doi.org/10.3389/fvets.2023.1303984.
DOI: https://doi.org/10.3389/fvets.2023.1303984

Interpretive Summary: Weaning is a stressful time for piglets, and often results in reduced growth and performance. Traditionally, in-feed antibiotics were administered to promote growth. However, such practices are now limited, and alternatives are needed. The role of bacterial microbiota members in host health is relatively well established, but less attention has been paid to fungal members of the gastrointestinal tract (GIT) community, or mycobiome. Human studies indicate that the mycobiome plays a critical role in health, and fungal probiotics which modulate gut microbiota may benefit piglet health. Here, we test Kazachstania slooffiae, a piglet gut commensal, as a probiotic candidate in the weanling pig, and also describe fungal and bacterial communities along the GIT. This is the first characterization of mucosal fungal communities at multiple times points in the developing piglet. Although no effect was observed on the growth or global health of piglets after K. slooffiae administration, diet, sow, and the environment did shape fungal and bacterial GIT populations. Together, these data provide a strong foundation for future studies which target the piglet mycobiome and ultimately contribute to the design of effective therapeutics which target the piglet gut to improve health.

Technical Abstract: As in-feed antibiotics are phased out of swine production, producers are seeking alternatives to facilitate improvements in growth typically seen from this previously common feed additive. Kazachstania slooffiae is a prominent commensal fungus in the swine gut that peaks in relative abundance shortly after weaning and has beneficial interactions with other bacteriome members important for piglet health. In this study, piglets were supplemented with K. slooffiae to characterize responses in piglet health as well as fungal and bacterial components of the microbiome both spatially (along the entire gastrointestinal tract and feces) and temporally (before, during, and after weaning). Litters were assigned to one of four treatments: no K. slooffiae (CONT); one dose of K. slooffiae 7'days before weaning (day 14; PRE); one dose of K. slooffiae at weaning (day 21; POST); or one dose of K. slooffiae 7'days before weaning and one dose at weaning (PREPOST). The bacteriome and mycobiome were analyzed from fecal samples collected from all piglets at day 14, day 21, and day 49, and from organ samples along the gastrointestinal (GI) tract at day 21 and day 49. Blood samples were taken at day 14 and day 49 for cytokine analysis, and fecal samples were assayed for antimicrobial resistance. While some regional shifts were seen in response to K. slooffiae administration in the mycobiome of the GI tract, no remarkable changes in weight gain or health of the animals were observed, and changes were more likely due to sow and the environment. Ultimately, the combined microbiome changed most considerably following the transition from suckling to nursery diets. This work describes the mycobiome along the piglet GI tract through the weaning transition for the first time. Based on these findings, K. slooffiae administered at this concentration may not be an effective tool to hasten colonization of K. slooffiae in the piglet GI tract around the weaning transition nor support piglet growth, microbial gut health, or immunity. However, diet and environment greatly influence microbial community development.