Effect of Long-Term Feeding of Graded Levels of Deoxynivalenol to Grower-Finisher Pigs

The prevalence of deoxynivalenol (DON) concerns swine producers in Western Canada. There has been extensive research into the effects of DON in pigs, much of which targets young animals and/or in short-term studies. The objectives of this thesis were to determine the effects of long-term exposure to DON-contaminated diets on growth performance, carcass characteristics, and health in finisher (Exp. 1) and grower-finisher (Exp. 2) pigs. In experiment 1, 200 pigs were housed in groups of 5 pigs/pen (n=10 pens/treatment) for a 6-wk feeding trial. In experiment 2, 240 pigs housed in groups of 6 pigs/pen (n=10 pens/treatment) were used in an 11-wk feeding trial. Pigs were fed a control diet without DON (CONT) or the basal diet with 1, 3, or 5 ppm DON (DON1, DON3, and DON5, respectively). Weekly pig BW and pen-wise feed intake was recorded to determine average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). Blood samples were collected on d 0, 14, and 42 for Exp. 1 and d 0, 14, and 42 and on d 42, 56, and 84 for Exp. 2. Serum was analyzed for liver and kidney health and immune response to a vaccine challenge. Carcass data was collected at the end of Exp. 2. In both studies, nitrogen (N)-balance was conducted to determine the effect of DON on N-utilization. In Exp. 1, pigs fed DON3 and DON5 had consistently reduced (P 0.05) on ADFI, ADG, and G:F. N-retention was reduced (P 0.05) but ADFI during the first week was lower (P 0.05) on G:F. Finisher N-balance results showed no impact of DON intake on N-retention (P > 0.05), however, N-retention was reduced in the grower pigs fed DON3 and DON5 diets (P 0.05) on carcass traits, health, or immune response. The lack of effect on G:F suggests negative effects of DON on growth performance are largely due to impaired feed intake. Overall, the performance was less affected in the grower-finisher study relative to the finisher study. Further, regardless of age, there was evidence that pigs can adapt to DON over the long-term. This information will allow producers to adjust feeding programs to account for reduced performance due to dietary DON