LAUSR

Pharmacological zinc (2,000-3,000 ppm) is commonly fed to nursery pigs to improve health and growth due to its antimicrobial and anti-inflammatory properties. The objective was to test if pharmacological zinc at time of oral Salmonella vaccination impeded vaccine efficacy. Sixty-four weaned pigs (5.1±0.7 kg BW) were used in a 2 x 2 factorial design. The diets were control (CON) or zinc (3,000 ppm for 1 week, 2,000 ppm for 2 weeks, and no additional zinc for 1 week [ZN]). On d 2 pigs were orally vaccinated for Salmonella with 1 of 2 commercially available vaccines, resulting in 4 treatments (CON1, CON2, ZN1, ZN2; n = 16/treatment). On d 28, n = 8 pigs/treatment were randomly selected and enrolled in a S. Typhimurium challenge study. On d 35 post-weaned, all pigs were inoculated with 108 cfu of a field S. Typhimurium isolate. Pig performance, febrile response, fecal shedding and serology was assessed over a 7-d challenge period. On dpi 7 all pigs were euthanized, and colon contents and ileocecal lymph nodes were collected for culture. The effect of nursery diet, vaccine and their interaction was assessed. Pigs were confirmed Salmonella culture positive at dpi 2 and 6 pigs were culture positive from the ileocecal lymph nodes at dpi 7. Salmonella-specific antibody titers (S/P) increased (P < 0.001) from dpi 0 (0.31) to 7 (2.01), and a time-by-vaccine interaction was reported (P < 0.05). Irrespective of diet and vaccine, core temperatures increased from 39.5°C (dpi 0) to 39.7°C (dpi 2) before decreasing (P = 0.02). Over the challenge period, ADG did not differ (0.67, 0.64, 0.61, 0.62 kg/d, CON1, CON2, ZN1, ZN2, respectively, P = 0.654). Furthermore, ADFI and G:F did not differ by diet or vaccine (P >0.05). In conclusion, pharmacological Zn did not inhibit efficacy of oral Salmonella vaccines.