Biochemical composition, lipoperoxidation, Na(+)/K(+)ATPase activity and reproduction of Hyalella castroi (amphipoda, dogielinotidae) fed with different diets.

This study compared the effect of different diets on the biochemical composition (lipids, cholesterol, proteins and glycogen) and the levels of lipoperoxidation and activity of Na(+)/K(+)ATPase of Hyalella castroi. We also investigated some patterns of the life cycle including survival, precopulatory mating pairs and number of ovigerous females after 21 days of culture with different diets. These crustaceans live in limnetic environments of the plateau (1,200 m a.s.l.) of the state of Rio Grande do Sul, in southern Brazil. Adult animals were collected in the autumn of 2006 in São José dos Ausentes. In the laboratory, the animals were kept submerged in aquariums, separated by sex, under controlled conditions. They were fed ad libitum for 21 days with different diets, and then some were used for biochemical determinations and others for observations of reproductive aspects. Statistical analysis revealed significant differences in the responses to glycogen, total proteins, lipoperoxidation levels and Na(+)/K(+)ATPase activity in both sexes of these amphipods and total lipids and total cholesterol levels only in females. These diets changed the biochemical patterns of the animals taken from the natural environment, and allowed a high survival rate but did not improve reproduction.