Effect of Intermittent Feed Deprivation on Plasma Insulin-Like Growth Factor-I and Tibial Dyschondroplasia in Broiler Chicks

摘要

Two experiments were conducted to evaluate dietary manipulation of growth rate and the subsequent incidence of tibial dyschondroplasia (TD) in broiler chicks. A corn-soybean meal diet which contained 1.15 % calcium and approximately 0.6 % available phosphorus (aP) was fed. In Experiment 1, birds were fed ad libitum or deprived of feed for 8 h during the night either three times per week on Monday, Wednesday and Friday or twice a week on Monday and Friday starting at d 5. In the second experiment, birds were full fed vs depriving feed for 8 h during the day every third day beginning at d 6. Feed deprivation decreased 20-d BW only in Experiment 1 when feed was deprived three times per week. Gain:feed was decreased in both experiments when the birds were restricted fed. The incidence of TD was decreased by 25 to 33 % and the number of severe TD lesions was decreased by 50 to 80 % when feeding time was restricted. Bone ash was not affected in Experiment 1, but was increased in Experiment 2 by feed deprivation. Plasma insulin-like growth factor-I (IGF-I) was decreased by feed deprivation, and returned to control levels after feed was returned. The results indicate that feed deprivation for eight hours at various daily intervals will attenuate the incidence of TD in birds fed a Ca:aP ratio of 2:1. This may be related to temporary reductions in circulating levels of IGF-I.