256 - Effect of Functional Amino Acid Supplementation in Salmonella-challenged Weaned Pigs Fed Either Animal- or Plant-based Nursery Diets

Abstract: Feeding plant based (PB) nursery diets may aggravate the effects of disease in pigs, which may be attenuated by functional amino acid (FAA) supplementation. The objective was to determine the effects of nursery dietary protein source and FAA supplementation in pigs subsequently challenged with Salmonella (ST). Thirty-two pigs (8.7 ± 0.23 kg) were assigned to 1 of 4 diet programs for 4 wk post-weaning in a 2 × 2 factorial with dietary protein source [PB vs. animal-based (AB)] with basal (FAA–) or supplemented FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements). Pigs were then placed onto a common grower diet and, after a 7-d adaptation period, were inoculated with ST (3.0 × 10⁹ CFU/mL) and monitored for 7 d post-inoculation. Growth performance, fecal score, gut health, ST shedding, intestinal colonization and translocation were measured pre- and post-inoculation. Nursery fecal score was decreased in AB-FAA+ pigs compared with the other groups (0.42 vs. 0.68±0.06 score; P< 0.05) and post-inoculation fecal score was increased in PB compared to AB pigs (1.12 vs. 0.95±0.15 score; P< 0.05). Overall ST shedding (2.20 vs. 2.42±0.22 score), cecal (1.69 vs. 2.50±0.36 score) and colonic ST colonization (2.05 vs. 2.83±0.36 score), and cecal myeloperoxidase (1.92 vs. 2.65±0.37 µU/mL) were reduced in AB compared with PB pigs (P< 0.05). Translocation of ST to spleen was decreased by FAA+ compared with FAA- (0.88 vs. 1.50±0.36 score; P< 0.05). Post-inoculation, AB pigs had greater weight gain compared with PB-FAA- (0.72 vs. 0.52±0.07 kg/d; P< 0.05). Pigs fed AB-FAA- had increased feed intake compared with PB-FAA- (1.45 vs. 1.17±0.08 kg/d; P< 0.05). Gain:feed was increased in AB-FAA+ compared with PB-FAA- pigs (0.54 vs. 0.44±0.05 kg/kg; P< 0.05). Pigs fed PB nursery diets were more susceptible to a subsequent ST challenge, and FAA supplementation attenuated the negative effects of PB diets in ST-challenged pigs.