The Effect of Dietary Cholecalciferol, 25-Hydroxycholecalciferol and 1,25-Dihydroxycholecalciferol on the Development of Tibial Dyschondroplasia in Broiler Chickens in the Absence and Presence of Disulfiram

Abstract

Four experiments were conducted to determine the effect of dietary cholecalciferol (vitamin D3), 25-hydroxycholecalciferol (25-OHD3) and 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) on the changes in growth, feed efficiency and bone ash, and the incidence, severity and number of #3 scores of tibial dyschondroplasia caused by the addition of disulfiram to the diet. The basal diet used was low in calcium and high in phosphorus and chlorine and known to promote a high incidence of tibial dyschondroplasia in broiler chickens. The chickens in all experiments received enough ultraviolet radiation from fluorescent lights in the pens to nearly satisfy their need for vitamin D. The addition of disulfiram to the diet caused an increase in most of the measurements indicating development of tibial dyschondroplasia in all of the experiments, and caused a decrease in bone ash in two of the experiments and a decrease in growth and gain:feed in one experiment. The addition of D3 to a diet containing no D3 caused higher bone ash and lower incidence of tibial dyschondroplasia in the absence or presence of disulfiram. The effects of the addition of 25-OHD3 to diets containing approximately five times the requirement of D3 in the absence and presence of disulfiram caused variable results. The addition of 1,25-(OH)2D3 to the D3-supplemented diet in the absence or presence of disulfiram caused dramatic increases in bone ash and a decrease in most of the criteria used to measure development of tibial dyschondroplasia. There was no indication of interaction of the effects of D3, 25-OHD3 and 1,25-(OH)2D3 with the action of disulfiram.