Effects of phytase and 1,25-dihydroxycholecalciferol on phytate utilization and the quantitative requirement for calcium and phosphorus in young broiler chickens.
Three experiments were conducted to determine the effects of supplementing 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] and a commercial phytase product on Ca and P requirements of 0- to 21-d-old broiler males. These experiments were conducted with four levels of dietary Ca and P in corn-soybean diets with and without supplementation of 5 micrograms/kg of 1,25-(OH)2D3, 600 units/kg of phytase, and the combination of these supplements. The results show that these levels of phytase and 1,25-(OH)2D3 can replace up to 0.1% of the inorganic P for criteria such as BW, bone ash, and plasma P. Both supplements increased phytate P retention, whereas higher levels of Ca and P decreased phytate P retention. The addition of 1,25-(OH)2D3, but not phytase, reduced Ca requirements and decreased the incidence of tibial dyschondroplasia. The combination of these levels of phytase and 1,25-(OH)2D3 replaced 0.2% inorganic P for criteria such as BW, bone ash, and P rickets. Total dietary P requirements are estimated to be between 0.55 and 0.60% at the levels of phytase and 1,25-(OH)2D3, listed above, or 0.45% when the combination is added. The Ca requirements are estimated to be 0.77% when 1,25-(OH)2D3 is added to the diet and 0.9 to 0.95% when phytase is added.
Mitchell
R D
RD
Department of Poultry Science, University of Georgia, Athens 30602-2772, USA.
Edwards
H M
HM
D010832:6-Phytase / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002645:Chickens; D005527:Food, Fortified; D008297:Male; D009751:Nutritional Requirements; D010758:Phosphorus / Q000172:deficiency; D016226:Phosphorus, Dietary / Q000008:administration & dosage*; D010833:Phytic Acid / Q000378:metabolism*; D011201:Poultry Diseases / Q000517:prevention & control; D012279:Rickets / Q000517:prevention & control / Q000662:veterinary
D002136:Calcium, Dietary; D016226:Phosphorus, Dietary; D010758:Phosphorus; D010833:Phytic Acid; D010832:6-Phytase; D002117:Calcitriol