Effects of a combination of prebiotics, essential oils, and an acidifier on jejunal mucosa microbiota and immune responses in nursery pigs challenged with F18+ Escherichia coli

The objective of this study was to test the hypothesis that supplementation with a combination of prebiotics (inulin and yeast extract), essential oils, and an acidifier (lactic acid) could mitigate the negative impacts of F18⁺ Escherichia coli (E. coli) on intestinal health and growth performance of nursery pigs. Thirty-six nursery pigs (6.8 ± 0.3 kg) weaned at 21 d of age were assigned to 3 treatments in a randomized complete block design with initial body weight and sex as blocks. Pigs were fed for 28 d in 3 phases (d 0 to 10, 10 to 22, and 22 to 28, respectively). Treatments were NC (basal diet, no challenge), PC (basal diet, challenged with F18⁺ E. coli), and POA (basal diet supplemented with a combined mixture of inulin, yeast extract, essential oils, and lactic acid at 0.1%, challenged with F18⁺ E. coli). On d 7 and 8, pigs in the PC and POA were orally inoculated with F18⁺ E. coli with a total dose of 1.1 × 1010 CFU/pig. On d 28, pigs were euthanized to collect jejunal tissue and mucosa. Data were analyzed using preplanned contrasts (NC vs. PC and PC vs. POA) in the MIXED procedure of SAS. The PC increased (P < 0.05) the expression of interferon-γ in the jejunum compared with the NC, whereas the POA decreased (P < 0.05) it compared with the PC. The PC tended to reduce (P = 0.051) the expression of occludin in the jejunum compared with the NC, whereas the POA increased (P < 0.05) occludin compared with the PC. The PC tended to increase interleukin-6 (P = 0.064) and interleukin-8 (P = 0.080) and increased (P < 0.05) protein carbonyl in the jejunal mucosa compared with the NC, whereas the POA reduced (P < 0.05) tumor necrosis factor-α, interleukin-6, and protein carbonyl compared with the PC. The PC reduced (P < 0.05) jejunal villus height, whereas the POA increased (P < 0.05) it compared with the PC. The PC reduced (P < 0.05) overall average daily gain and gain:feed compared with the NC. The POA tended to reduce (P = 0.059) overall average daily feed intake compared with the PC without compromising average daily gain or gain:feed, suggesting that the reduction in feed intake did not negatively affect growth performance. In conclusion, supplementation with a combination of inulin, yeast extract, essential oils, and lactic acid reduced intestinal inflammation and oxidative damage, and improved intestinal integrity and morphology in F18+ E. coli challenged pigs, whereas growth performance remained unaffected.