Effect of niacin additions to corn-soybean meal diets on performance of pigs from weaning to finishing.

An experiment was conducted to study the effect of adding crystalline niacin to low-protein diets on pig performance from weaning to market weight. Niacin was added at 0, 3, 9, 27, or 81 ppm to a low-protein test (LPT) diet fortified with crystalline amino acids and at 0 or 81 ppm to a positive control (PC) diet. Pens (four pigs/pen) were the experimental units with 12 and 8 pens per treatment during the 35-d nursery and 98-d growing-finishing phases, respectively. Niacin supplementation did not affect (P > .10) ADFI, ADG, gain:feed ratio, hair and skin condition, or the incidence of toe cracks and lameness during the nursery or the growing-finishing phases. There were no linear, quadratic, or cubic responses (P > .20) with increasing concentrations of added niacin in the LPT diets for the production criteria measured. Also, there were no interactions (P > .20) between niacin (0 or 81 ppm) and protein level (LPT or PC diets) for any of the criteria studied. Pigs fed the PC diets had greater (P < .05) ADFI, ADG, and gain:feed ratios over the entire experiment than pigs fed the LPT diets that contained 0 or 81 ppm of added niacin. In conclusion, the addition of niacin to low-protein or positive control corn-soybean meal diets did not improve pig performance criteria from weaning to market weight.