The progression of deoxynivalenol-induced growth suppression in nursery pigs and the potential of an algae-modified montmorillonite clay to mitigate these effects
H. L.Frobose, J. A. Erceg, S. Q. Fowler, M. D. Tokach, J. M. DeRouchey, J. C.Woodworth, S. S. Dritz and R. D. Goodband
Two experiments were conducted to characterize the progression of deoxynivalenol(DON)-induced growth suppression and to investigate algae-modified montmorillonite clay (AMMC) as a means to alleviate the effects of DON in nursery pigs. In both experiments, naturally DON-contaminated wheat was used to produce diets with desired DON levels. In Exp. 1, 280 barrows and gilts (10.0 ±0.2 kg BW) were used in a 28-d experiment arranged in a 2 × 2 + 1 factorial design with 8 replicates per treatment. The 5 treatments consisted of 2 positive control (PC) diets with DON below detection limits and with or without 0 or 0.50% AMMC and 3 negative control (NC) diets with 5 mg/kg of DON and containing 0, 0.25, or 0.50% AMMC. No DON × AMMC interactions were observed. Overall, pigs fed DON had decreased (P < 0.001) ADG and final BW regardless of AMMC addition. Feeding DON-contaminated diets elicited the most severe depression (P < 0.001) in ADFI and G:F from d 0 to 3, remaining poorer overall (P < 0.01) but lessening in severity as exposure time increased. Pigs fed DON diets had greater (P < 0.05) within pen BW variation (CV) on d28. Although the addition of 0.50% AMMC to diets restored (P < 0.05) ADFI from d 14 to 21 to levels similar to the PC, no other differences were observed for AMMC inclusion. In Exp. 2, 360 barrows (11.4 ± 0.2 kg BW) were used in a 21-d experiment with 9 dietary treatments arranged in a 3 × 3 factorial design with DON and AMMC inclusion as main effects. There were 8 replicate pens per treatment. Treatments consisted of 3 PC diets without DON, 3 low-DON (1.5 mg/kgDON) NC diets, and 3 high-DON (3 mg/kg DON) NC diets with 0, 0.17, or 0.50% AMMC incorporated at each DON level. No DON × AMMC interactions were observed. As DON level increased, ADG and final BW decreased (quadratic, P < 0.05), driven by decreased (quadratic, P < 0.01) ADFI and poorer (quadratic; P <0.05) G:F. At both 1.5 and 3 mg/kg DON, reductions in ADG were most marked fromd 0 to 7 (15 to 22% lower) and were least distinct from d 14 to 21 (5 to 6%lower). Incorporating AMMC at increasing levels had no effect on ADG, ADFI,G:F, or final BW. Overall, these experiments reinforce DON effects on feed intake but also indicate that the effects of DON on G:F may be more severe than previously thought. Furthermore, some pigs appear to develop tolerance to DON, as effects on ADFI and G:F lessen over time. However, the addition of AMMC did not offset the deleterious effects of DON.