Integrated endocrine-oxidative-metabolic and trace element responses to heat and cold stress in dromedary camels...

The dromedary camel (Camelus dromedarius) possesses remarkable physiological adaptations to withstand harsh desert conditions, including heat stress and drought. This study aimed to evaluate the effects of heat and cold stress on oxidative stress biomarkers, hormones, lipid, and mineral concentrations in dromedary camels. A total of 45 apparently healthy adult male dromedary camels were included in the study. Blood samples were collected, plasma and serum were separated for the determination of oxidative stress biomarkers, hormones, metabolic, and trace mineral parameters.

During heat stress, cortisol, zinc, and copper concentrations increased significantly (p < 0.05), whereas total antioxidant capacity (TAC), triiodothyronine (T3), glucose, and triglyceride concentrations decreased significantly (p < 0.05). In contrast, cold stress was associated with significant (p < 0.05) increases in catalase (CAT), malondialdehyde (MDA), T3, glucose, and cortisol concentrations, while TAC, triglycerides, and copper concentrations decreased significantly (p < 0.05). Strong positive (p < 0.01) correlation between T3 and thyroxine (T4), whereas a strong negative (p < 0.01) correlation was observed between zinc and cholesterol. Positive (p < 0.05) correlations were also detected between glucose and MDA, cortisol and CAT, and copper and TAC. Conversely, negative (p < 0.05) correlations were found between triglycerides and CAT, triglycerides and T4, triglycerides and cortisol, zinc and triglycerides, cholesterol and glucose, and copper and MDA. During summer, positive correlations were observed between glucose and MDA, T3 and T4, as well as between cholesterol and both T3 and T4. In contrast, glucose showed negative correlations with both T3 and T4, while zinc was negatively correlated with copper. During autumn, positive correlations were detected between CAT and TAC, T3 and T4, and glucose and zinc. Conversely, negative correlations were observed between triglycerides and TAC, cortisol and T4, glucose and cholesterol, and zinc and cholesterol. During winter, T3 was positively correlated with zinc but negatively correlated with TAC.

Cold stress exerted a more pronounced effect on oxidative balance and metabolic activity in dromedary camels than heat stress. Regular monitoring of these parameters is recommended for the early detection of physiological disturbances during the cold season.