Effects of diet complexity, antibiotics, and benzoic acid on nursery pig growth performance

Abstract Text: Two 28-d experiments were used to determine the effects of diet complexity, antibiotics, and benzoic acid on nursery pig (PIC 327 × 1050) growth performance. Both experiments were arranged as 2 × 2 factorials with main effects of benzoic acid (Vevovitall, DSM Nutritional Products, Parsippany, NJ) and diet complexity (Exp. 1) or antibiotics (Exp. 2). Each experiment had 6 or 7 pigs per pen and 10 pens per treatment. In Exp. 1, 280 pigs (initially 7.0 kg) were used. Benzoic acid levels were 0 or 0.5% fed from d 0 to 28. Diet complexities (simple or complex) were fed from d 0 to 14 followed by a 14-d common diet.  Complex diets contained 10% dried whey, 1.25% select menhaden fish meal, 1.25% spray-dried blood cells, and 0.25% zinc oxide and simple diets did not contain lactose, zinc oxide, or specialty protein sources. No interactions were detected between diet complexity and benzoic acid and no benzoic acid main effects were observed. From d 0 to 14, pigs fed simple diets had decreased (P<0.001) ADG (186 vs 277 g), ADFI (304 vs 381 g) and G:F (0.612 vs 0.726). From d 14 to 28, pigs previously fed simple diets tended to have increased (P<0.06) ADG (585 vs 567 g) and increased (P<0.003) G:F (0.679 vs 0.651). Overall (d 0 to 28), pigs fed simple diets had decreased (P<0.001) ADG (386 vs 417 g) and ADFI (581 vs 626 g). In Exp. 2, 240 pigs (initially 7.3 kg) were used. Benzoic acid levels were 0 or 0.5% fed from d 0 to 28. Antibiotic (carbadox) levels were 0 or 55 ppm from d 0 to 14 and 0 or 27.5 ppm from d 14 to 28. From d 0 to 14, pigs fed diets without antibiotic tended to have increased (P<0.07) G:F (0.736 vs 0.710). From d 14 to 28, pigs fed diets without antibiotic had decreased (P<0.01) ADG (553 vs 603 g), ADFI (857 vs 903 g), and G:F (0.646 vs 0.668). Overall (d 0 to 28), pigs fed diets without antibiotic had decreased (P<0.02) ADG (422 vs 449 g) and ADFI (626 vs 662 g). No main effects of benzoic acid were observed. In conclusion, pigs fed complex diets or antibiotics had improved growth performance, but no differences were observed from including benzoic acid in the diets.

Keywords: benzoic acid, diet complexity, pig