Effect of citric acid and microbial phytase supplementation on ileal digestibility of crude protein, apparent metabolizable energy, Ca and total P of broilers

An experiment was conducted to study the effect of microbial phytase supplementation and citric acid on ileal digestibility of some nutrients. A total of 270 Ross 308 male broilers were used in a 3×3 factorial arrangement design with three levels of citric acids (0, 3 and 6%) and three levels of phytase enzyme (0, 500 and 1000 enzyme IU/kg) on a randomized complete block design, with 9 experimental diets, 3 replicates and 10 birds per each replicate. The experimental diets were formulated based upon corn-soybean meal. Ileal digestibility of crude protein, apparent metabolizable energy, total P and Ca of broiler chicken were determined on day 35. The results showed that there was a significant (P<0.01) improvement effect of diet containing 3% citric acid on ileal digestibility of crude protein, apparent metabolizable energy and total P (P<0.01), but had no significant effect on digestibility of Ca. Also, diets having 6% citric acid significantly reduced ileal digestibility of crude protein, apparent metabolizable energy and total P (P<0.01) compared to diets having no acid or 3% citric acid (P<0.01). All different levels of microbial phytase improved nutrients digestibility of diets (P<0.01). The results also strongly showed that there is an interaction between citric acid and microbial phytase and acid has a synergetic effect on phytase efficiency in improvement of nutrients digestibility.