Available phosphorus reduction in weaned piglets’ diets containing phytase combined with butyric and benzoic acids

Abstract

This study aimed to evaluate the reduction of available phosphorus (Pa) in the diet of weaned piglets using phytase combined with butyric and benzoic acids. A total of 120 piglets with initial weight of 6.7 ± 0.02 kg were used in a randomized block design with six treatments: control; reduction of 0.15% Pa (Pa red); Phytase + Pa red; Phytase + butyric acid + Pa red; Phytase + benzoic acid + Pa red; Phytase + butyric acid + benzoic acid + Pa red; five replicates, with four animals each. The experimental diets had no influence on the fecal scores, Escherichia coli count, or the pH of the digestive tract. An improved villus:crypt ratio was found when the combination of phytase with butyric and benzoic acids was used. The histomorphometry of the jejunum and of the ileum showed no differences with respect to villus height, crypt depth, and villus:crypt ratio. The bones of the piglets fed with a diet containing reduced levels of available phosphorus showed less resistance to fracture. The levels of calcium in the raw bones were lower in the piglets that received a diet containing phytase and butyric acid. Reduced phosphorus deposition was observed in the bones of animals that received the diet containing phytase, butyric acid, and benzoic acid. It is concluded that the inclusion of phytase and butyric and benzoic acids, and their combination, in the diet of weaned piglets does not affect the pH of the stomach, duodenum, jejunum, ileum, cecum, and colon, and does not change the frequency of diarrhea or the E. Coli count. The association of butyric and benzoic acids with phytase in the diet of piglets after weaning improves the villus:crypt ratio of the duodenum. The use of phytase (1000 UF/kg) allows the formulation of diets for weaned piglets with a 0.15% reduction in the level of available phosphorus without damaging the concentration of calcium and phosphorus in the bones and without altering bone resistance.