Effects of an all-natural feed additive on the gut microbiome of weanling pigs experimentally infected with a pathogenic Escherichia coli

Homeostasis of the gut microbial ecosystem is essential for optimal growth performance and disease resistance in post-weaning pigs. A220 is a formulated feed additive that features a blend of a proprietary toxin-adsorbing mineral with a select blend of phytogenics shown to have antibacterial properties against a variety of gram-negative and positive bacterial pathogens. This study aimed to assess the effects of A220 on the gut microbiome and further relate this to changes in growth performance and post-weaning diarrhea outcomes in pigs challenged with an enterotoxigenic Escherichia coli (ETEC). At 21 d of age, 36 piglets were weaned and randomly allocated to 1 of 3 groups: control (CON) or A220 supplemented at 0.25 or 0.5%. After a 7-d adaptation, all pigs were orally inoculated with 10¹⁰ cfu of F18 ETEC once daily from d 0 to d 2 post-inoculation (PI). Fecal consistency was scored twice daily from d 0–21 PI. Microflora in ileal digesta, ileal mucosa and fecal samples were profiled using 16S rRNA sequencing on d −7, 0, 7, and 21 PI. A220 supplementation at both levels increased feed efficiency from d 14–21 PI and reduced diarrhea frequency during the study (P < 0.05). Compared with CON, 0.5% A220 supplementation increased the relative abundance of Firmicutes, but reduced Bacteroidetes and Proteobacteria in feces on d 7 PI (P < 0.05). Within Firmicutes phylum, A220 at both 0.25% and 0.50% increased the relative abundance of Lactobacillaceae on d 7 PI (P < 0.05). A220 at both levels increased the relative abundance of Prevotellaceae and decreased that of Rikenellaceae in ileal digesta on d 21 PI (P < 0.05). A220 at 0.5% increased the relative abundance of Clostridiaceae and Prevotellaceae, and decreased that of Enterobacteriaceae and Succinivibrionaceae in ileal mucosa on d 21 PI (P < 0.05). A220 supplementation modified gut microbiota in favor of promoting a well-balanced gut microbial ecosystem, which may contribute to enhanced disease resistance and improved growth performance in weanling pigs faced with pathogenic challenges.

Key Words: microbiome, enterotoxigenic Escherichia coli (ETEC), post-weaning, pig.

Presented at the 9th Symposium on Gut Health in Production of Food Animals, St. Louis, USA, 2021. For information on the next edition, click here.