Protective Effect of Phytogenic based Additives in Enterotoxigenic Escherichia Coli Challenged Piglets

Post Weaning Diarrhea (PWD) is the most important multifactorial gastroenteric disease of the weaning in pig livestock. Phytogenic (PHY) natural extracts are largely studied as alternatives to antibiotic treatments in combating the global concern of the antimicrobial resistance. The aim of this study was to evaluate the protective effect of innovative phytogenic premix with or without short and medium chain fatty acids (SCFA and MCFA) in O138 E. coli challenged piglets. Twenty-seven weaned piglets were allotted into four groups receiving different diets according to the following experimental doses: PHY1 (n=7) fed basal diet supplemented with 0.2% of phytogenic premix, PHY2 (n=7) fed basal diet supplemented with 0.2% of phytogenic premix added with 2000 ppm of SCFA and MCFA. After 6 days of feeding experimental diets, animals were challenged (day 0) with 2x109 CFU/dose of E. coli and CTRL group fed basal diet was divided at day 0 into positive (CTRL+; n=6) and negative control group (CTRL-; n=7). Body weights were recorded at -14, -6, 0, 4 and 7 days and the feed intake was recorded daily. E. coli shedding was monitored for 4 days post-challenge by plate counting. Fecal consistency was registered daily by a four-point scale (0-3; diarrhea >1) during the post-challenge period. Tissue samples were obtained for gene expression and histological evaluations at day 7 from four animals per group. Lower average feed intake was observed in CTRL+ compared to PHY2 and CTRL during the post-challenge period. Infected groups showed higher E. coli shedding compared to CTRL- during the 4 days post-challenge (p<0.01). PHY2 showed lower frequency of diarrhea compared to PHY1 and CTRL+ from 5 to 7 days post-challenge. No significant alterations among groups were observed in histopathological evaluation. Duodenum expression of occludin tended to be lower in challenged groups compared to CTRL- at 7 days post-challenge (p=0.066). In conclusion, dietary supplementation of PHY plus SCFA and MCFA revealed encouraging results for diarrhea prevention and growth performance in weaned piglets.