Interaction of Dietary Phytase and Glutamic Acid on Bone Ash Response in Chicken Thigh

Abstract

The optimum pH of phytase originated from Aspergillus niger is approximately 5.5. In the present study, we tried to modify the intraluminal pH by dietary acidic amino acid to maximize phytase activity. Single Comb White Leghorn male chicks at 7 days of age were fed the experimental diets for 10 days. The experiment was 2×2×2 factorial arrangement of treatments with two dietary amino acid sources (L-glutamine or L-glutamic acid at 50g/kg diet), two levels of dietary phytase (0 or 1,000U/kg diet) and two levels of dietary available P supplementation (0 or 6g/kg diet). The glutamic acid supplementation significantly reduced pH in the crop (5.4±0.2; n=7) compared with the glutamine supplementation (6.0±0.1; n=7). There was a significant interaction between dietary amino acid source and phytase level on bone ash response in the thigh. Dietary phytase significantly increased bone ash content in chicks fed diets containing glutamic acid but not in the glutamine group. These results suggest that the modification of pH in the crop could activate phytase in chickens.

Keywords

• chicken
• phytase
• glutamic acid
• bone ash content