Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 12/22/2015
Publication Date: N/A
Technical Abstract: Common industry practice is to segregate sick pigs; however, the same diet is provided. Due to the higher nutrient demand of the activated immune system, we hypothesized pigs would choose diets differing in nutrient content during an immune challenge when given choices. This study examined pig feed preference changes in response to an oral Salmonella challenge. Pigs (n=30; 6.9+/-0.1 kg body weight) had ad libitum access to water and a common antibiotic-free (AF) phase 1 diet that was provided in 4 feeders within each pen from day 0 to 7 postweaning (pw). On day 7 pw, pigs were provided 4 AF phase 2 diets differing in composition: 1) Control (CON); 2) High Fat (HF; 33.75Kcal/kg>CON; 3) Low Protein (LP; 1.22%CON). Pigs were provided the diets in 4 separate feeders within each pen, with order randomized within and between pens from day 7 to 28 pw. On day 14 pw, pigs were separated into 2 treatments: 1) Salmonella (SAL; n=24) were orally inoculated with 4.8x10^9 colony forming units/pig Salmonella Typhimurium; and 2) Negative control (NC; n=6) were orally administered PBS. Pigs were weighed on days -1, 7, 14, 21, and 28 pw and feeders were weighed daily from days 7 to 28 pw. Prior to analysis, feed disappearance data was summed into 7 day intervals. Feed disappearance data were analyzed as a MANOVA using the GLM procedure in SAS; pen was the subject, treatment was a fixed effect, and significant weekly weight change was included as a covariate. There was a treatment x time interaction (P=0.0003) for weight; SAL pigs weighed less than NC pigs at day 21 (14.0+/-0.3 vs. 16.4+/-0.6 kg) and 28 pw (19.5+/-0.3 vs. 22.3+/-0.6 kg). There was a trend (P=0.135) for an overall treatment x time effect. Specifically, SAL pigs consumed more LCHP diet than NC pigs during day 7 to 14 (P=0.009; 1.4+/-0.1 vs. 0.3+/-0.2 kg) and day 14 to 21 (P=0.017; 1.3+/-0.2 vs. 0.3+/-0.3 kg); SAL pigs consumed less LP diet than NC pigs day 14 to 21 pw (P=0.037; 0.8+/-0.1 vs. 1.5+/-0.3 kg); SAL pigs tended (P=0.0815) to consume more CON diet than NC pigs during days 21 to 28 pw (1.8+/-0.2 vs. 0.9+/-0.4 kg). These data suggest nursery pigs consumed more of a LCHP diet and less of a LP diet during a Salmonella challenge, and consumed more of a CON diet 7 to 14 days post-challenge compared to non-challenged pigs. Further research must be conducted to determine if these diet choices would enhance recovery and performance in pigs exposed to Salmonella.