title: Comparison of dietary 25-hydroxycholecalciferol and cholecalciferol in broiler chickens.
abstract: We conducted a series of 10 feeding trials involving over 36,000 broilers. The effects of various dietary levels of cholecalciferol (vitamin D3) or 25-hydroxycholecalciferol (25-OH-D3) were compared using a "basal" dosage level of 69 micrograms/kg feed, as well as levels ranging from .5 to 1.5 times the basal level. For all 10 studies, average body weight increased by an average of .042 +/- .03 kg (P < .001) and adjusted feed efficiency decreased (improved) by an average of .026 +/- .0046 kg/kg (P < .001) in birds fed 25-OH-D3 in comparison to those fed vitamin D3 at the basal level. Changes in mortality were not detected. Evaluation of different dietary levels of 25-OH-D3 revealed a significant dose-response relationship, with maximal effects on weight gain, feed efficiency, and breast meat yield being observed in the range of 50 to 70 micrograms/kg feed. Preliminary studies with different levels of vitamin D3 suggested no additional benefits on weight gain or feed efficiency with higher dietary levels of vitamin D3. Serum 25-OH-D3 concentrations increased more rapidly in birds fed 25-OH-D3 than in birds fed vitamin D3. There were significant correlations with body weight, feed conversion, and serum 25-OH-D3 concentrations, with no correlations observed between serum 1,25-(OH)2D3 concentrations and these variables.
mesh_terms: D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D002112:Calcifediol / Q000494:pharmacology*; D002645:Chickens / Q000254:growth & development / Q000502:physiology; D002762:Cholecalciferol / Q000494:pharmacology*; D008136:Longevity; D014807:Vitamin D / Q000378:metabolism
chemical_list: D014807:Vitamin D; D002762:Cholecalciferol; D002112:Calcifediol