The oxidative cost of reproduction in female and male Semaprochilodus taeniurus

Long migrations are carried out by animals for various ecological purposes, with reproduction being one of the most important. During this process, the energy demand is increased, requiring adjustments at the physiological level to deal with high energy consumption and the consequent associated oxidative stress. To test the oxidative stress as a physiological cost of reproduction, hematological parameters, antioxidant enzyme and oxidative damage in the heart and liver of female and male Semaprochilodus taeniurus were measured at the end of the reproductive migration after the animals were collected in the Negro River, near the Lake Catalão, Amazon basin. The following haematological parameters were analysed: hematocrit, haemoglobin concentration, number of erythrocytes, corpuscular constants (MCV, HCM, CHCM), plasma glucose and lactate levels. Oxidative stress was indirectly quantified via measurements of the antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase) and directly quantified by measuring markers of oxidative damage using the comet assay, which indicates levels of damage to the DNA molecule, and lipid peroxidation, which indicates damage to lipids of cell membranes. The results showed higher values of mean corpuscular hemoglobin (HCM), glucose, glutathione S-transferase, superoxide dismutase, lipid peroxidation and DNA damage in males compared to females. The number of erythrocytes was high in females. Based on the results, we concluded that oxidative stress was higher in males than in females, suggesting that reproductive migration results in a higher physiological cost for males than for females of this species.