146 Efficacy of Zinc Glycinate Reducing Zinc Oxide on Growth and Intestinal Health of Nursery Pigs Challenged with F18+Escherichia Coli

Abstract

Abstract The objective of this study was to investigate the effect of ZnGly supplementation reducing ZnO in feeds on growth performance and intestinal health of nursery pigs challenged with F18+Escherichia coli (E. coli). A total of 56 nursery pigs (initial BW = 6.5 ± 0.5 kg) were allotted to 7 treatments based on a randomized complete block design using BW and sex as blocks. Treatment groups were: 1) NC: no-challenged with E. coli; 2) PC: challenged with F18+E. coli; 3) challenged with F18+ E. coli and fed ZnO at 2,500 mg/kg in the diet; (4 to 7) challenged with F18+E. coli and fed ZnGly at 400 mg/kg and ZnO at 0, 700, 1,400, and 2,357 mg/kg in the diets. Pigs were fed for 28 days based on 2 phases (Phase 1: 14 d and phase 2: 14 d) and 48 pigs were orally inoculated with F18+ E. coli (6 × 109 CFU/mL) on d 7. Pigs were euthanized on d 28 to collect tissues to evaluate TNF-α, IL-8, malondialdehyde, protein carbonyl, gene expression of Zn transporters, and mucosa-associated microbiota in the jejunum. Data were analyzed by Mixed procedure of SAS. The E. coli challenge tended to decrease (P = 0.076) ADG (200 to 155 g/d) and (P = 0.055) G:F (0.82 to 0.69) during phase 1, and increased (P < 0.05) fecal score (3.2 to 4.1) of nursery pigs during d 7 to 14. There was no difference on the growth performance during the overall period, although pigs fed with the pharmaceutical level of ZnO had greater (P < 0.05) ADG (343 vs. 256 g/d) than pigs fed with ZnGly at 400 mg/kg during the first week of post-challenge. Supplementation of ZnGly with reducing the levels of ZnO from 2,357 to 0 mg/kg tended to have a quadratic response on the fecal score (maximum 4.2 at 667 mg/kg of ZnO) during post-challenge period. Supplementation of ZnGly with reducing levels of ZnO from 2,357 to 0 mg/kg linearly decreased (P < 0.05) IL-8 (0.94 to 0.58 ng/mg) and malondialdehyde (0.49 to 0.34 μM/mg) in jejunum of the pigs. Supplementation of ZnGly reducing the levels of ZnO from 2,357 to 0 mg/kg linearly increased (P < 0.05) Chao1 (142.2 to 148.7) and decreased (P < 0.05) Shannon (4.08 to 3.99) with quadratic effects (P < 0.05) on relative abundance of Pseudomonadaceae (minimum 6.15% at 1,000 mg/kg) and Streptomycetaceae (minimum 5.91% at 800 mg/kg) at family level in jejunum of the pigs. In conclusion, ZnGly supplementation at 400 mg/kg could effectively reduce the use of ZnO in nursery feeds by having similar effects to the pharmaceutical use of ZnO without negatively affecting growth performance and intestinal health of pigs challenged with F18+E. coli.