Oxidative stress associated with paternal care in smallmouth bass (Micropterus dolomieu)

In species that provide parental care, care for offspring is often accompanied by an increase in locomotor activity and a decrease in feeding opportunities which can negatively impact endogenous energy reserves. Depletion of parental energy stores and declines in nutritional condition can cause physiological disturbances, such as an imbalance between free radical production and available antioxidants, known as oxidative stress. Using the teleost smallmouth bass (Micropterus dolomieu) as a model, we tested if the energetic challenge associated with sole paternal care was associated with oxidative stress. Blood samples from parental males were collected throughout parental care, during egg, embryo, and larval stages of offspring development, and assayed for both antioxidant capacity and oxidative damage. A reduction in oxygen radical absorbance capacity was observed during the parental care period, indicating a decrease in resistance to oxidative stress. Although no change was observed in the reduced:total thiol ratio, a significant increase in the concentration of both oxidized and total thiols occurred during the parental care period. No increase in the oxidative stress markers 8-hydroxy-2-deoxyguanosine, protein carbonyls and lipid peroxides was observed. We concluded that oxidative stress did not occur as a result of parental care in the male smallmouth bass. This study provides evidence that participation in energetically taxing activities, such as parental care, can result in a decrease in antioxidant resources, but may not always result in oxidative stress.