Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3.
Commercial and laboratory-strain crossbred chicks responded (P < .01) markedly to 1alpha-hydroxycholecalciferol (1alpha-OH D3) during the 2nd and 3rd wk of life. Bone-ash responses exceeded 50% when this compound was added at 20 microg/kg to phosphorus (P)-deficient corn-soybean meal diets containing surfeit levels (25 microg/kg) of cholecalciferol (D3). Phosphorus excretion was decreased (P < .01) and, thus, retention was increased (P < .01) when 1alpha-OH D3 was supplemented. A P-deficient (.10% P) casein-amino acid purified diet, devoid of D3, was used to determine whether 15 microg/kg of D3 was sufficient to facilitate optimal absorption of the nonphytate P contained in this diet. Bone ash responded to .075% P addition (KH2PO4), and chicks fed diets with .175% nonphytate P exhibited further bone-ash responses to 15 microg/kg of D3 or 10 microg/kg 1alpha-OH D3. Higher levels of either of these D3 compounds did not produce additional responses. This suggested that 15 to 25 microg/kg of D3 in a P-deficient corn-soybean meal diet (.28% phytate P and .14% nonphytate P) is more than adequate to facilitate optimal absorption of the nonphytate P present in the diet. A P-deficient casein-dextrose diet (.13% nonphytate P and 15 microg/kg D3) was fed in the final chick assay, and chicks fed this diet did not show bone ash responses to 1alpha-OH D3 or to microbial-derived phytase (1,470 units/kg). Thus, with P-deficient corn-soybean meal diets containing at least 15 microg D3/kg, 1alpha-OH D3 supplementation markedly increased weight gain and bone ash because it increased the utilization of phytate P.
Biehl
R R
RR
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
Baker
D H
DH
D000818:Animals; D002645:Chickens / Q000378:metabolism* / Q000502:physiology; D002762:Cholecalciferol / Q000032:analysis / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D005260:Female; D006887:Hydroxycholecalciferols / Q000032:analysis / Q000494:pharmacology; D008903:Minerals / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics*; D016226:Phosphorus, Dietary / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology; D010833:Phytic Acid / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics*; D011897:Random Allocation; D013025:Glycine max / Q000737:chemistry / Q000378:metabolism; D013977:Tibia / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects / Q000502:physiology; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism
D006887:Hydroxycholecalciferols; D008903:Minerals; D016226:Phosphorus, Dietary; D002762:Cholecalciferol; D010758:Phosphorus; C028705:bone ash; D010833:Phytic Acid; C008088:alfacalcidol