期刊
INTERNATIONAL JOURNAL OF BIOMETEOROLOGY
卷 59, 期 1, 页码 79-87出版社
SPRINGER
DOI: 10.1007/s00484-014-0826-4
关键词
Diurnal variations; Hot dry season; Broiler chickens; Photoperiods; Melatonin
Experiments were performed with the aim of determining the effect of melatonin administration on diurnal fluctuations in cloacal temperature (CT) of Marshall broiler chickens during the hot dry season. Birds in group I (12L:12D cycle) were raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation, while those in group II (LL) were kept under 24-h continuous lighting, without melatonin administration. Broiler chickens in group III (LL + melatonin) were raised under 24-h continuous lighting, with melatonin supplementation at 0.5 mg/kg per os. The cloacal temperatures of 15 labeled broiler chickens from each group were measured at 6:00, 13:00, and 19:00 h, 7 days apart, from days 14-42. Temperature-humidity index was highest at day 14 of the study, with the value of 36.72 +/- 0.82 A degrees C but lowest at day 28 with the value of 30.91 A +/- 0.80 A degrees C (P < 0.0001). The overall mean hourly cloacal temperature value of 41.51 A +/- 0.03 A degrees C obtained in the 12L:12D cycle birds was significantly higher (P < 0.001) than the value of 41.16 A +/- 0.03 A degrees C recorded in the melatonin-treated group but lower than that of 41.65 A +/- 0.03 A degrees C obtained in the LL birds. Mortality due to hyperthermia commenced at day 28 in both 12L:12D cycle and LL broiler chickens but was delayed till day 42 in LL + MEL broiler chickens. In conclusion, melatonin administration alleviated the deleterious effects of heat stress on broiler chickens by maintaining their cloacal temperature at relatively low values.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据