Ameliorative effects of melatonin administration and photoperiods on diurnal fluctuations in cloacal temperature of Marshall broiler chickens during the hot dry season

Abstract

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 °C but lowest at day 28 with the value of 30.91 ± 0.80 °C (P < 0.0001). The overall mean hourly cloacal temperature value of 41.51 ± 0.03 °C obtained in the 12L:12D cycle birds was significantly higher (P < 0.001) than the value of 41.16 ± 0.03 °C recorded in the melatonin-treated group but lower than that of 41.65 ± 0.03 °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.

Melatonin MT1 and MT2 Receptors Exhibit Distinct Effects in the Modulation of Body Temperature across the Light/Dark Cycle

“…Clinical studies have shown that exogenous administration of MLT suppresses the physiological increase in T b observed during daytime [32,33] and has hypothermic properties at the dose of 5 mg/kg [34,35,36,37,38]. Similar results have been demonstrated in preclinical studies in diurnal animals in which administration of MLT acted as a hypothermic agent in the active/light phase in fat sand rats and Marshall broiler chickens [39,40]. However, the neurobiological mechanism through which MLT exerts this hypothermic effect, as well as the selective contribution of the three MLT receptor subtypes, are yet to be investigated.…”

Daily rhythms of cloacal temperature in broiler chickens of different age groups administered with zinc gluconate and probiotic during the hot-dry season

“…; Sinkalu et al. ). The high THI may render evaporative cooling mechanism ineffective in the broiler chickens.…”

“…The t cloacal values were recorded as an indicator of the core body temperature (Sinkalu et al. ), with the aid of a digital clinical thermometer (KRAUSE digital thermometer (R) , DK‐5550, Langeskov, Denmark). The t cloacal was measured, concurrently with the thermal environmental parameters for 3 days only, 1 week apart, in order to reduce the adverse effect of stress due to handling on the birds, known to increase the body temperature (Edgar et al.…”

Cloacal temperature responses of broiler chickens administered with betaine and ascorbic acid during the hot-dry season

“…The mechanism of action of AA has been linked to its antioxidant activity (Surai 2007), and ROS are generated in excess in birds exposed to heat stress (Kikusato & Toyomizu 2013). Therefore, it seems likely that AA scavenged the ROS produced in the birds subjected to heat stress (Sinkalu, Ayo, Abimbola, et al 2014;Sinkalu, Ayo, Adelaiye, et al 2014). Betaine, on the other hand, did not significantly alter CT values in broiler chickens, except at 14:00 h. That is, betaine may not be beneficial in reducing body temperature responses in broiler chickens exposed to heat stress.…”

“…CT was obtained (as a measure of core body temperature; Sinkalu, Ayo, Abimbola, et al 2014;Sinkalu, Ayo, Adelaiye, et al 2014) using a digital thermometer (Kruuse Incorporated, Denmark). The thermometer was inserted about 3 cm into the cloaca and tilted to make contact with the wall of the cloaca.…”