Taurine Supplementation Modulates Circadian Rhythms of Heat-associated Cytokines in Male Broiler Chickens Reared under Hot-dry Conditions

An experiment was designed to study the modulatory effects of supplemental taurine on circadian rhythms of heat-associated cytokines in male broiler chickens of different ages under hot-dry conditions. Twenty, 21-day-old Arbor Acre male broiler chickens balanced for weight served as subjects and were assigned ten (10) each to control (Cgp) and treatment (Tgp) groups. The broiler chickens were fed on isonitrogenous and isocaloric commercial diets during the experimental period. Blood samples were collected from the wing veins from 10 chickens in each of the groups at four-hour intervals during a 24-h period on days 28, 35 and 42 of age. Harvested serum from blood samples were analysed for heat-shock protein 70 (HSP70), tumour necrosis factor-alpha (TNF-α) and interleukin 1-alpha (IL-1 α). Data obtained were fitted into the single cosinor application. The results showed that HSP70, TNF- α and IL-1α exhibited clear circadian rhythmicity in both groups. Taurine significantly (P < 0.05) decreased the overall mesors of HSP70, TNF- α and IL-1α. The acrophases in both groups were restricted to the photophase, however, taurine advanced the acrophases of TNF-α and IL-1α during the early photophase. It was concluded that taurine modulated the rhythms of the cytokines; influencing the rhythms of: HSP 70, TNF- α and IL-1α. Taurine modulated the rhythms by increasing the body temperature in young broiler chickens during the early photophase (low ambient temperature) and ameliorated heat-stress by combating oxidative stress and therefore, immunosuppression in broiler chickens during hot-dry condition.