Effects of a blend of essential oils and an enzyme combination on growth performance, microbial counts, and ileum morphology in Escherichia coli K88 challenged piglets

This study was conducted to evaluate the effects of nutritional supplement of a blend of essential oils (EO; thymol and cin- namaldehyde) and an enzyme combination (XB; xylanase and β- glucanase) either alone or in combination on the growth per- formance, microbial counts, and morphology in the ileum of weaned piglets challenged with Escherichia coli K88. One hun- dred and ninety-two piglets were weaned at 24 days and allocated to 8 treatments for a 35-d experiment with a 2×4 factorial design comparing oral E. coli challenges [sham (-) or infected (+)] and different dietary treatments [fed the basal diet (CTR) either without or with EO, XB, or their combination (EO + XB)]. On day 8, half of the piglets were orally inoculated with 4 mL E. coli 0149: F4 (K88). On day 35, forty-eight piglets (6 piglets/treatment) were slaughtered. E. coli challenge significantly (P<0.05) impaired the growth performance, induced severe diarrhea, and increased the populations of Clostridia, E. coli and Coliforms. In the unchallenged group, dietary EO reduced the Clostridia popu- lation in the feces on day 14 compared to the CTR group (P<0.05), and dietary XB or EO + XB decreased the E. coli count in the cecum digesta compared to the CTR group (P<0.05). In addition, dietary EO + XB decreased the crypt depth and increased the villus to crypt ratio of piglets compared to the CTR group (P<0.05). In the challenged group, XB and EO + XB sup- plementation improved the feed efficiency when compared to the CTR group during the last week of the trial (P<0.05), and dietary EO + XB reduced fecal consistency compared to the EO and XB groups at 1 day post-infection (P<0.05). Challenged piglets fed EO + XB had less Coliforms populations than the CTR animals in the feces on day 14 and in the digesta of cecum (P<0.05). Moreover, EO + XB piglets had lower crypt depth and higher V:C ratio than the CTR animals (P<0.05). The results suggest that the combination of EO and XB supplementation may improve the gut health status of post-weaning piglets by modulating fecal.