Characterization of the nutritional interactions between organic acids and inorganic bases in the pig and chick.

Four experiments were conducted to characterize the interactions between fumaric (FA), malic (MA), or citric acid (CA) and NaHCO3. In two experiments, seven diets were formulated containing 2.5% FA, MA, and CA, with or without 2.3, 1.9, or 1.4% NaHCO3, respectively, as well as a control diet (no addition of organic acids or NaHCO3) for 28-d-old pigs (Exp. 1, corn-soy protein concentrate-based diet) and 1-wk-old chicks (Exp. 4, corn-soy-based diet). In Exp. 1, at 2 and 4 wk, the FA+NaHCO3 treatment resulted in greater average daily gain (ADG) and feed intake (ADFI) compared with the control (P < .05). In Exp. 2, 28-d-old pigs were fed corn-soy diets with .9, 1.6, and 2.3% NaHCO3 in addition to 2.5% FA. After wk 2, there was a quadratic response in ADG (P < .08) and ADFI (P < .05) when increasing levels of NaHCO3 were added to the diet. This was true at wk 4 for both ADG and ADFI (P < .05). In Exp. 3, finishing pigs were fed corn-soy diets containing 2.5% FA or 2.5% FA + 2.3% NaHCO3 added to a control diet. No effect (P < .05) of FA or NaHCO3 was observed. In Exp. 4, the combination of CA+NaHCO3 or MA+NaHCO3 was superior to FA+NaHCO3 for ADG (P < .08) and ADFI (P < .05) when fed to young chicks.