Because the data did not meet the parameters of normality and
homoscedasticity, non-parametric statistical analyses were performed,
eliminating from the database those extreme values that
were identified as outliers through Grubbs' test. To probe for significant
differences in the concentrations of trace elements, oxidative
damage and antioxidant enzyme activity between tissues (muscle,
liver and kidney) and between sexes Kruskal–Wallis tests and median
test were applied (Durán et al., 2003). Spearman correlation matrices
were used to analyze potential relationships between trace element
concentrations and oxidative stress indicators. All statistical analyses
were performed using Statistica