Characterisation of antioxidant defences in three Antarctic notothenioid species from Terra Nova Bay (Ross Sea)

Oxidative challenge is an important factor affecting the adaptive strategies of Antarctic fish, but data on antioxidant defences in these organisms remain scarce. In this investigation, individual antioxidants and the total oxyradical scavenging capacity (TOSC) were characterised in three notothenioid species, Trematomus bernacchii, Trematomus hansoni and Trematomus newnesi; seasonal fluctuations were further analysed in T. bernacchii sampled during different periods of the reproductive cycle, ice melting and phytoplanktonic blooms. The overall results revealed only limited differences between the three notothenioids, with greater TOSC values in T. hansoni and T. newnesi. The capacity for decomposing hydrogen peroxide via catalase was not particularly enhanced in these fish, in contrast to the prominent role of the enzyme in Antarctic invertebrates. An alternative antioxidant strategy, based on the efficiency of low molecular mass scavengers was suggested, especially for T. bernacchii which had higher lev...