Effect of added calcium carbonate without and with benzoic acid on weanling pig growth performance, fecal dry matter, and blood Ca and P concentrations.

The objective of these studies was to determine the effects of increasing levels of calcium carbonate (CaCO 3 ) with and without benzoic acid on weanling pig growth performance, fecal dry matter (DM), and blood Ca and P concentrations. In experiment 1, 695 pigs (DNA Line 200 × 400, initially 5.9 ± 0.02 kg) were used in a 28 d study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens and then pens were allotted to one of five dietary treatments. Treatment diets were fed from weaning (day 0) to day 14, with a common diet fed from days 14 to 28. Dietary treatments were formulated to provide 0%, 0.45%, 0.90%, 1.35%, and 1.80% added CaCO 3 at the expense of ground corn. From days 0 to 14 (treatment period), average daily gain (ADG) and G:F decreased (linear, P  ≤ 0.01) as CaCO 3 increased. From days 14 to 28 (common period) and for the overall experiment (days 0 to 28), there was no evidence of differences in growth performance between treatments. For fecal DM, there was a trend (quadratic, P  = 0.091) where pigs fed with the highest CaCO 3 diets had the greatest fecal DM. Experiment 2 used 360 pigs (DNA Line 200 × 400, initially 6.2 ± 0.03 kg) in a 38 d study. Upon arrival to the nursery facility, pigs were randomly assigned to pens and then pens were allotted to one of six dietary treatments. Dietary treatments were fed in three phases with treatment diets fed from days 0 to 10 and days 10 to 24, and a common phase 3 diet fed from days 24 to 38. Dietary treatments were formulated to provide 0.45%, 0.90%, and 1.35% added CaCO 3 with or without 0.5% benzoic acid (VevoVitall, DSM Nutritional Products, Parsippany, NJ) added at the expense of ground corn. There was no evidence ( P  > 0.05) for any CaCO 3 by benzoic acid interactions. For the experimental period (days 0 to 24), there was a tendency for benzoic acid to increase ADG ( P  = 0.056), average daily feed intake (ADFI; P  = 0.071), and gain-to-feed ratio (G:F; linear, P  = 0.014) as CaCO 3 decreased. During the common period (days 24 to 38), pigs previously fed benzoic acid had increased ( P  = 0.045) ADG and marginally increased ( P  = 0.091) ADFI. For the overall study, pigs fed benzoic acid had increased ADG ( P  = 0.011) and ADFI ( P  = 0.030), marginally increased G:F ( P  = 0.096) and final body weight ( P  = 0.059). Serum Ca decreased (linear, P  < 0.001) as CaCO 3 decreased in the diet. These data show that decreasing the CaCO 3 content in the nursery diet immediately after weaning may improve ADG and G:F. Dietary addition of benzoic acid may also provide beneficial effects on ADG and ADFI, regardless of dietary Ca level.