title: Effects of particle size on the biological availability of calcium and phosphorus in defluorinated phosphate for chicks.
abstract: A total of 576 d-old, male, broiler chicks were used in two trials 1) to determine the range of Ca and P levels over which the response in bone characteristics is linear and 2) to determine the influence of particle size of defluorinated rock phosphate (DFP) on the bioavailability of Ca and P in DFP. Six treatments were used in Experiment 1 in which varying percentages of added Ca (.00, .06, .12, .24, .36, and .48%) and added P (.00, .05, .10, .20, .30, and .40%) were evaluated in a corn-soybean meal diet containing 23% CP, .47% Ca, and .39% P (.14% available P). Weight gain, feed intake, and tibia breaking strength increased (P less than .001) with increasing levels of dietary Ca and P. Treatments in Experiment 2 consisted of: 1) Diet 1, a corn-soybean meal basal diet (23% CP, .50% Ca, .46% P, .21% available P), 2) Diet 1 with .12% added Ca from calcium carbonate (CC) and .07% added P from monosodium phosphate (MSP), 3) Diet 1 with .24% added Ca from CC and .14% added P from MSP; and 4 to 8), Diet 1 with .24% added Ca and .14% added P from five particle sizes of DFP. Feed intake, weight gain, and tibia breaking strength and ash percentage increased linearly (P less than .01) and feed:gain ratio decreased quadratically (P less than .10) with increasing percentages of added Ca and P in Diets 1 to 3.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
authors.forename: T W
authors.initials: TW
authors.lastname: Burnell
authors.forename: G L
authors.initials: GL
authors.lastname: Cromwell
authors.forename: T S
authors.initials: TS
authors.lastname: Stahly
mesh_terms: D000818:Animals; D001682:Biological Availability; D002118:Calcium / Q000493:pharmacokinetics*; D002645:Chickens / Q000378:metabolism*; D004435:Eating; D008297:Male; D008863:Microspheres; D010316:Particle Size; D010710:Phosphates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010758:Phosphorus / Q000493:pharmacokinetics*; D011897:Random Allocation; D012044:Regression Analysis; D012995:Solubility; D015430:Weight Gain
chemical_list: D010710:Phosphates; D010758:Phosphorus; D002118:Calcium