Effects of sodium metabisulfite additives on nursery pig growth

Sodium metabisulfite (SMB)-based feed additive efficacy was evaluated in three nursery pig growth experiments where pigs were fed diets containing low deoxynivalenol (<1.5 mg/kg; DON) concentrations. Pigs were weaned at approximately 22 d of age and randomly allotted to pens with one pen of 27 gilts and one pen of 27 barrows per feeder; thus, feeder was the experimental unit. In experiment 1, a total of 2,268 pigs were used in a 35-d trial with 21 feeders per treatment. Experimental treatments included a control diet or the control with 0.50% SMB-based Product 1 (Defusion; Provimi, Brookville, OH) fed in phase 1 and 0.25% fed in phases 2 and 3, then all pigs were fed a control diet for the last week of the study. Pigs fed Product 1 had greater (P < 0.05) ADG, ADFI, and G:F compared with pigs fed the control diet from days 0 to 28. However, from days 28 to 35, the opposite response was observed with pigs fed the control diet having greater ADG and G:F than pigs previously fed Product 1. Despite this response, pigs fed Product 1 were heavier (P < 0.05) on day 35 than control-fed pigs. In experiment 2, a total of 4,320 pigs were used in a 42-d trial. Pigs were fed a control diet or diets with SMB-based either Product 1 or Product 2 (NutriQuest, Mason City, IA) at different concentrations and durations. Among the various treatments, Product 1 or Product 2 concentrations ranged from 0.50% initially to 0.25%, 0.15%, or none the last week of the study. Overall, pigs fed either of the additives at the highest concentrations and for the longest period of time had greater (P < 0.05) ADG and ADFI compared with pigs fed the control diet, with those fed lower concentrations or shorter durations being intermediate. In experiment 3, a total of 2,808 pigs were used in a 28-d trial with 13 feeders per treatment. All pigs were fed a common diet for 7 d after weaning. Pigs were then fed either a control diet (without any SMB-containing product) or a diet containing Product 1 (0.50% and 0.25% from days 0 to 21 and 21 to 28, respectively) or SMB (0.50% and 0.25% from days 0 to 21 and 21 to 28, respectively) or 0.25% SMB from days 0 to 28. Overall, pigs fed Product 1 or high-SMB diets had greater (P < 0.05) ADG compared with pigs fed low-SMB or control diets. In conclusion, results of these experiments indicate that in diets with low DON concentrations, these SMB-based products increased ADG compared with control diets.