The effects of citric acid on phytate-phosphorus utilization in young chicks and pigs.

Abstract

Several bioassays were conducted with young chicks and pigs fed phosphorus (P)-deficient corn-soybean meal diets. With diets for chicks containing .62% Ca and .42% P (.10% available P), graded doses of a citric acid + sodium citrate (1:1, wt:wt) mixture (0, 1, 2, 4, or 6% of diet) resulted in linear (P < .01) increases in both weight gain and tibia ash. Relative to chicks fed no citric acid, tibia ash (%) and weight gain (g/d) were increased by 43 and 22%, respectively, in chicks fed 6% citric acid. Additional chick trials showed that 6% citric acid alone or sodium citrate alone was as efficacious as the citric acid + sodium citrate mixture and that 1,450 U/kg of phytase produced a positive response in bone ash and weight gain in chicks fed a diet containing 6% citrate. Varying the Ca:available P ratio with and without citrate supplementation indicated that citric acid primarily affected phytate-P utilization, not Ca, in chicks. Moreover, chicks did not respond to citrate supplementation when fed a P-deficient (.13% available P), phytate-free casein-dextrose diet. Young pigs averaging 10 to 11 kg also were used to evaluate citric acid efficacy in two experiments. A P-deficient corn-soybean meal basal diet was used to construct five treatment diets that contained 1) no additive, 2) 3% citric acid, 3) 6% citric acid, 4) 1,450 U/kg phytase, and 5) 6% citric acid + 1,450 U/kg phytase. Phytase supplementation increased (P < .01) weight gain, gain:feed, and metatarsal ash, whereas citric acid addition increased only gain:feed (P < .05) and metatarsal ash (P < .08). A subsequent 22-d pig experiment was conducted to evaluate the effect of lower levels of citric acid (0, 1, 2, or 3%) or 1,450 U/kg phytase addition to a P-deficient corn-soybean meal diet. Phytase supplementation improved (P < .01) all criteria measured. Weight gain and gain:feed data suggested a response to citric acid addition, but this was not supported by fibula ash results (P > .10). The positive responses to phytase were much greater than those to citric acid in both pig experiments. Thus, dietary citric acid effectively improved phytate P utilization in chicks but had a much smaller effect in pigs.

Valor nutricional da silagem de grãos úmidos de milho com diferentes graus de moagem para leitões na fase de creche

“…Estas respostas talvez estejam relacionadas com uma provável ação favorável do processo de ensilagem sobre as moléculas de fitato, aumentando a disponibilidade do fósforo e do cálcio. Além disso, alguns autores constataram que ácidos orgânicos podem melhorar a utilização do cálcio e fósforo em dietas para leitões desmamados e suínos em terminação (Han et al, 1998;Boling et al, 2000), devido à diminuição do pH estomacal.…”

Effect of microbial phytase and diet fermentation on ileal and total tract digestibility of nutrients and energy in growing pigs

“…Therefore, lowering the pH of gastrointestinal digesta might increase the efficacy of supplemental phytase. Indeed, there are several experiments demonstrating a synergistic effect of diet acidification and phytase supplementation on P availability in pigs (Jongbloed et al, 1996;Kemme et al, 1997;Li et al, 1998) even though it is unclear whether this effect is due to the lower pH or the presence of the acid, mostly citric acid, itself (Han et al, 1998;Boling et al, 2000). Moreover, organic acids are metabolized in the body and intestinal digesta have a relatively strong buffering capacity, which suggests that a significant effect of diet acidification on the gastrointestinal tract pH can hardly be expected.…”

Scientific Opinion on the safety and efficacy of citric acid when used as a technological additive (preservative) for all animal species

“…A linear increase in performance parameters of piglets was reported when citric acid was added to the diet at 15 000 and 30 000 mg/kg (four pens of two animals/treatment) for four weeks (Radcliffe et al, 1998). Boling et al (2000) conducted two experiments (three replicates of three piglets/treatment; duration of study 18-22 days) to evaluate whether the addition of citric acid (30 000 and 60 000 mg/kg feed) to a phosphorus-deficient maize-soybean meal diet would improve phytate phosphorus utilisation in weaned piglets. Significant positive effects on bone mineralisation and on the performance of the animals were reported with the citric acid supplemented diets.…”