Coenzyme Q homologs and trace elements content of Antarctic fishes Chionodraco hamatus and Pagothenia bernacchii compared with the mediterranean fish Mugil cephalus

Abstract

Coenzyme Q and trace element contents of two antarctic fishes (Pagothenia bernacchii and Chionodraco hamatus) were investigated and compared with that of one temperate marine fish (Mugil cephalus). In particular, muscle and erythrocyte concentrations of coenzyme Q, vitamin E, selenium, copper and zinc were determined. Antarctic fishes showed, at the level of their muscles, higher levels of selenium, zinc and copper compared with M. cepalus. In antarctic fishes, in the place of Q₁₀, the coenzyme Q form generally observed in temperature fishes, only the homolog coenzyme Q₉ was found. This particular finding has been related to the difference in the crystallization temperature existing between CoQ₁₀ and CoQ₉. Moreover, the high levels of zinc and selenium, observed in C. hamatus, correlate very well with a recent report on the presence, in the liver of this fish, of a zinc-binding protein that, in addition, is characterized by an amino acid sequence closely similar to that of a selenium-containing protein isolated from ovine heart. All together, the results indicate, for the antarctic species, a high level of antioxidant defenses with respect to the mediterranean fish and may be considered as a stimulating basis for further studies on the oxidative metabolism of Antarctic organisms.