Branchial tissue intermediate metabolism of the crayfish Parastacus varicosus (Decapoda: Parastacidae) in Rio Gravataí Basin, Rio Grande do Sul State, Brazil

Abstract

Specialized literature has demonstrated, in Decapods, that anterior gills are morphologically and physiologically adapted for gas exchange and breathing, while the posterior gills are specialized for osmorregulation. The goal of this work was to analyze the seasonal variations of the intermediate metabolism of the gills of Parastacus varicosus, relating variation of these metabolites with ecological and behavioral factors of the animal and abiotics factors. Crayfishes were collected from June/2004 until May/2005 in Gravataí, Rio Grande do Sul State, Brazil. Gills were removed and separated in anterior and posterior parts for determination of the levels of glycogen, proteins and lipids. The results were analyzed with ANOVA followed by Bonferroni test. For the comparision between males and females and anterior and posterior gills was used the two-way ANOVA test. Both tests were made with a significant level of 0.05 in the Statistical Package for the Social Sciences (SPSS-11.5) software. The results showed a bigger consumption of the glycogen and lipids in the males in relation to the females for anterior gills. This pattern can be related to the agonist behaviors of the males and the increase of the activity of exploration of the environment mainly in search of reproductive partners. The gills of P. varicosus act in different way in relation to its position (anterior and posterior) and sex, showing a clear seasonal variation. The storage and the consumption of the metabolites in each season differ between the sexes and the localization of the gills. These differences can be occurring due to environmental factor, behavioral or the addition of both of these factors.