Route of fecal microbiota transplantation delivery determined the dynamics and predictability of donor microbe colonization

Fecal microbiota transplantation (FMT) and the colonization of delivered donor microbes has been reported to improve the negative effects (decrease in body weight, diarrhea, and gut barrier disruption) associated with weaning in pigs. However, delivery of FMT in pigs is still invasive and predicting the colonization or rejection of donor microbes remains challenging. Therefore, this study developed a non-invasive in-feed delivery of FMT and evaluated the effect of FMT mode of delivery on growth performance, gut physiology, microbiota dynamics, and predictability of colonization or rejection of donor microbes in recipient pigs. Forty weaned piglets (10 per group) were administered FMT through one of three routes; oral, rectal, or amended in-feed. The control group was orally administered sterile saline to simulate handling stress. Pigs in the FMT groups had higher average daily weight gain (ADG) from day 0–2 post-weaning. An increase in community diversity and a shift in the recipient community towards the donor in all FMT groups was observed on day 5. The oral group had the highest colonization (15.12%) and the lowest rejection (19.34%) rates, while colonization was 13.82% and 11.78% in rectal and in-feed group respectively. On day 4, colon crypt depth was increased in all FMT groups but an increase in villus length was only observed in the in-feed group. Colonization and rejection of donor microbes in the recipient animals could be predicted in all routes of administration, but the efficacy of prediction was influenced by the route of delivery. In-feed FMT had the lowest colonization prediction which may have been influenced by the need for voluntary consumption of fecal materials in the in-feed group. The ten most abundant genera (Prevotella, Alloprevotella, Phascolarctobacterium, Lactobacillus, Cloacibacillus, Bacteroides, Lachnoclostridium, Escherichia-Shigella, unclassified Lachnospiraceae sequences, and archaea Methanobrevibacter) in the recipient prior to FMT (background community) was the most important feature in predicting colonization for all routes of fecal microbiota transplant. FMT administered as a lyophilized feed additive shows promise in altering microbiome community structure. While colonization and rejection of donor microbes within the recipient community are predictable, the efficacy of these predictions varies with the route of transplant. This suggests that different prediction models are necessary for each delivery mode of FMT in pigs.