Abstract
Due to the challenge of weaning pigs and the need to reduce the use of antimicrobials in animal feed, there is a growing need to look for nutraceutical alternatives to reduce the adverse effects of the post-weaning period. We evaluate the effect of different feed nutraceutical additives on the microbial communities, gut health biomarkers, and productivity of pigs during the post-weaning period. The study involved 240 piglets weaned on the 21st day of age and randomized to six different diets: D1-BD commercial standard feed, D2-AGP: D1 + 150 ppm zinc bacitracin, D3-MD: D1 + 550 ppm maltodextrin, D4-FOS: D1 + 300 ppm fructo-oligosaccharides, D5-EO: D1 + 70 ppm Lippia origanoides essential oil, and D6-SH: D1 + 750 ppm sodium humate. On day 30 post-weaning, zootechnical parameters were evaluated, and jejunal samples were taken to obtain morphometric variables, expression of barrier and enzymatic proteins, and analysis of microbial communities. Animals fed D4-FOS and D5-EO had the lowest feed conversion ratio and higher expression of barrier and enzymatic proteins compared to D1-BD, D2-AGP, and D3-MD. The use of the additives modified the gut microbial communities of the piglets. In conclusion, fructo-oligosaccharides and Lippia origanoides essential oil were the best alternatives to zinc bacitracin as antibiotic growth promoters.