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Weaned pig responses to Escherichia coli lipopolysaccharide challenge when receiving dietary yeast-based nucleotides
This study investigated the response of piglets receiving a nucleotide-rich yeast extract (NRYE) without or with feed enzymes (ENZ) and antimicrobial growth promoters (AGP) on performance, blood cell profile, serum and ileum cytokines, and gut structure after an Escherichia coli lipopolysaccharide ( LPS) challenge. Thirty-six pigs were allotted to 6 diets including: a non-challenged control (CON); LPS-challenged control (LPS); LPS + AGP; LPS + NRYE; LPS + ENZ; and LPS + ENZ + NRYE. On day 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge (hpc). After 96 hpc, pigs were euthanized to obtain duodenum, jejunum and ileum tissues. Overall (d 1 to 11), NRYE supplementation tended to attenuate LPS-induced reduction in gain/feed ratio (P = 0.096), but LPS + AGP pigs had higher body weight (P = 0.04) and average daily gain (P = 0.03) than LPS + NYRE pigs. At 6 hpc, LPS + NRYE and LPS + ENZ + NRYE pigs had lower (P < 0.05) plasma urea N (PUN) and higher (P < 0.05) platelet count than LPS pigs. At 96 hpc, LPS-induced villus atrophy in the jejunum and duodenum was attenuated (P < 0.05) in LPS + ENZ + NRYE pigs. At 6 hpc, serum TNF-α and IL-10 concentration was reduced (P < 0.05) and increased (P < 0.05), respectively, in pigs receiving AGP, NRYE, and ENZ + NRYE. At 96 hpc, compared with LPS pigs, ileal TNF-α expression was lowered in LPS + NRYE (P = 0.01) and LPS + ENZ + NRYE (P = 0.01) pigs, whereas ileal IL-1β and IL-10 expression was lower in all treatments (P< 0.05). In conclusion, LPS challenged piglets fed diets supplemented with NRYE without or with enzymes expressed similar beneficial responses as those fed diets with AGP in terms of lowering PUN concentration, reducing duodenal and ileal villi atrophy, and downregulating serum and ileal proinflammatory cytokines. This suggests that supplementation of NRYE can promote the health of piglets during early weaning in antibiotic-free feeding regimens.
Keywords:
lipopolysaccharide; nucleotide-rich yeast extract; piglet