The effect of sodium bicarbonate or potassium bicarbonate on acid-base status and protein and energy digestibility in swine

Abstract

Three experiments were conducted to evaluate the effects of Na or K on acid-base status and nutrient utilization in young growing pigs. These studies were carried out to develop a better understanding of the growth response to alkaline salts of these minerals that have been observed in lysine-deficient swine. In experiment 1, a 2×2 factorial arrangement of 2.2 g/kg vs. 7.4 g/kg Na and ad libitum vs. meal feeding regimens was used to evaluated the effects of Na on blood acid-base variables. Na was supplemented as the alkaline salt, NaHCO 3. For each treatment regimen, blood samples were collected via indwelling vena cava catheters every 2 hr for 28 hr. Sodium supplementation increased (P<0.05) blood HCO 3 − and base excess and tended (P<0.07) to increase pH. Plasma urea N was depressed (P<0.05) by the meal feeding regimen. In experiment 2, the effect of NaHCO 3 (1.3% or 2.6%) or KHCO 3 (3.0%) on apparent nutrient digestibility and nitrogen balance was investigated utilizing pigs fitted with simple T cannulas in the ileum near the ileocecal junction. A 4×4 Latin square design was used. KHCO 3 or 2.6% NaHCO 3 increased (P<0.05) urinary volume and increased (P<0.05) urine pH. NaHCO 3 had no effect (P<0.05) on apparent digestibility of lysine, tryptophan, nitrogen or energy or on nitrogen balance. KHCO 3 decreased (P<0.05) energy digestibility. In experiment 3, the effect of 2.6% NaHCO 3 on gastrointestinal pH was studied. No effects (P>0.05) were observed in the stomach, duodenum, jejunum, ileum, cecum or colon. NaHCO 3 or KHCO 3 alter the acid-base balance of the pig. However, their growth-promoting effects in lysine-deficient pigs are not due to enhanced lysine or protein digestibility