75 Diet acid-binding capacity-4 influences nursery pig performance and fecal dry matter

A total of 360 pigs (initial body weight = 5.9 kg) were used to evaluate the effects of increasing acid-binding capacity-4 (ABC-4) of the diet on nursery pig performance and fecal dry matter (DM). At weaning, pigs were allotted to 1 of 6 dietary treatments. There were 5 pigs/pen and 12 replications/treatment. Pigs were fed experimental diets in two phases with phase 1 from d 0 to 10 post-weaning followed by phase 2 from d 10 to 23. Diets were formulated with increasing ABC-4 levels ranging from 150 meq/kg (diet 1, low ABC-4) to 312 meq/kg (diet 5, high ABC-4) in phase 1 and 200 meq/kg (diet 1, low ABC-4) to 343 meq/kg (diet 5, high ABC-4) in phase 2. For diet 1, low ABC-4 diets were formulated using specialty soy protein concentrate (AX3 Digest; Protekta; Newport Beach, CA) at 12.5 and 10.0% of the diet in phase 1 and 2, respectively. The low ABC-4 diet also utilized fumaric and formic acid at 0.50 and 0.48% of the diet, respectively, for both phase 1 and 2. For diets 2 (medium low), 3 (medium), 4 (medium high), and 5 (high), increasing dietary ABC-4 was achieved by progressively decreasing the level of acidifiers and replacing specialty soy protein concentrate with enzymatically treated soybean meal (HP 300; Hamlet Protein; Findlay, OH) on an SID Lys basis. Diets 1 through 5 were formulated without the addition of pharmacological levels of Zn from ZnO. For diet 6, a positive control diet was used which had the same formulation as the highest ABC-4 diet but with the addition of 3,000 and 2,000 mg/kg of Zn from ZnO in phase 1 and 2, respectively. Following phase 2, all pigs were fed a common diet until d 38 of the study. In the experimental period and overall, there was a quadratic response observed (P ≤ 0.030) where body weight (BW) and average daily gain (ADG) were greatest for pigs fed the medium low and medium ABC-4 diets (Table). During the experimental period, increasing ABC-4 decreased (linear, P = 0.002) gain to feed ratio (G:F). For overall G:F, a quadratic response was observed (P = 0.023) where G:F was most improved for pigs fed the medium low and medium ABC-4 levels. For fecal DM, increasing ABC-4 decreased (linear, P ≤ 0.036) fecal DM on d 10 and 17, with no differences on d 23. Pigs fed the diet with pharmacological levels of Zn from ZnO had increased (P ≤ 0.038) ADG compared with pigs fed diets without ZnO during the experimental period and overall. In summary, a dietary ABC-4 level of 203 and 247 meq/kg for phase 1 and 2, respectively, was most beneficial to improve both growth performance and fecal DM in weanling pigs.