Pineal–adrenal–immune system relationship under thermal stress: effect on physiological, endocrine, and non-specific immune response in goats

摘要

The purpose of the investigation was to observe the pineal–adrenal–immune system relationships and their influence on non-specific immune response in female goats under short-term thermal stress. Six female goats had been exposed to 40°C and 60% relative humidity in the psychrometric chamber for 17 days. Blood samples were obtained on days 0 and 10 to establish control and thermal stress effects, respectively. Chemical adrenalectomy was achieved by injecting metyrapone (100 mg/kg body weight) followed by exogenous melatonin treatment (0.1 mg/kg body weight) from 11th to 17th day of experiment. Thermal stress significantly (P ≤ 0.05) altered the physiological responses. Metyrapone and melatonin treatment significantly (P ≤ 0.05) reduced the thermal-stress-induced increase in plasma concentrations of cortisol and corticosterone while significantly (P ≤ 0.05) increased the plasma melatonin on days 11 and 17. Furthermore, these treatments significantly (P 0.05) increased the phagocytic activity of neutrophils as compared to both control and thermal exposure values from 11–17 days of experiment. The data generated from this study help us to understand the functional relationship between pineal, adrenal, and immune system, and how this relationship modifies the non-specific immune response for the well being of goats during thermal stress.