Indicators of oxidative stress in leukocytes isolated from bottlenose dolphins (Tursiops truncatus) in response to a proinflammatory challenge

Few studies have analyzed the indicators of oxidative stress in marine mammals following exposure to lipopolysaccharides (LPS); sex and maturity-related differences have not been explored. The objective of this study was to compare the indicators of oxidative stress following exposure to LPS for 24 and 48 h in isolated Pacific bottlenose dolphin (Tursiops truncatus; N = 12) leukocytes in relation to sex and maturity stage, using spectrophotometry. Following 48 h under experimental conditions (10 μg LPS mL⁻¹), the leukocytes from males (n = 5) produced significantly more superoxide radical (O₂^•-; F (1, 8) = 13.965, p = 0.006) and displayed significantly greater activities of catalase (CAT; F (1, 8) = 9.465, p = 0.015) and glutathione S-transferase (GST; p = 0.028) compared to the leukocytes from females (n = 7). Following 48 h under experimental conditions, maturity-stage did not significantly influence the indicators of oxidative stress. Mature bottlenose dolphins (n = 7) had a significantly higher average daily dietary intake compared to immature bottlenose dolphins (n = 5; F (1, 10) = 5.825, p = 0.036). These results suggest that sex-related strategies for coping with a proinflammatory challenge may be present within the leukocytes from bottlenose dolphins, while potential maturity stage-related strategies require further investigation.