EVALUATION OF INTESTINAL INFLAMMATORY AND PERMEABILITY MARKERS IN PIGLETS FED MEDICATED TRANSITION DIETS

The aim of this study was to evaluate the inflammatory and intestinal integrity response of piglets fed with or without antimicrobials added to their transition diets. For this purpose, eighty piglets ((LD x LW) x Pietrain) were weaned at 21 d of age (6.4 ± 0.1 kg body weight (BW)) and divided into two groups according to their diet: control diet (C) and control diet with antimicrobials (AMA: 300 ppm amoxicillin, 120 ppm colistin sulfate and 2500 ppm ZnO). Piglets were housed in groups of 5 (n = 8) and fed ad libitum a prestarter diet (weaning to d 14 after weaning (a.w.)) and a starter diet (d 15-42 a.w.). BW and feed intake were measured weekly from weaning until the end of the trial. To evaluate effects of antimicrobials on gut integrity, expression in tight junction protein genes (ZO-1, Occludin, E-Cadherin) and inflammatory markers (IL-1β, IL-8, COX-2, iNOS and TNF-α) was measured in ileal samples, as well as TEER and Isc evaluation in Ussing Chambers. Performance and ex-vivo data were analyzed using a mixedeffect model, and gene expression data were analyzed using Student’s t-test. Performance data did not differ between treatments. The AMA group showed a reduction in ileal mRNA abundance of certain inflammatory markers, such as COX-2 (P < 0.05), compared to the C group. No differences were observed in either the expression of tight junction genes or in TEER and Isc measurements. Antimicrobials may have an intestinal anti-inflammatory effect when added continuously to piglet feed, and they do not modulate zootechnical performance or gut integrity in non-challenging situations.