Tissue composition and haemolymphatic metabolites during gonadal development in Aegla platensis (Crustacea, Decapoda) maintained in experimental culture

Abstract

This study describes the variation of tissue composition and haemolymphatic metabolites in the anomuran crab A. platensis, which was maintained for 90, 120, 150, and 180 days under laboratory conditions, and relates the data collected to reproductive aspects of this species. Individuals were collected during the winter from Mineiro Creek, in Rio Grande do Sul, Brazil. Some of the individuals were killed when collected and the remaining animals were maintained in a laboratory for different time periods using a commercial diet. Haemolymph, hepatopancreas and gonads were removed at different times of cultivation to determine their biochemical composition using spectrophotometric methods. Hepatosomatic and gonadosomatic indexes were determined. Statistical analysis revealed significant differences between the sexes in all metabolites except in the proteins levels in the haemolymph. We observed an increase of ovigerous females kept under the same culture conditions between 120 and 150 days and we found an increase in the gonadosomatic index and a decrease in the hepatosomatic index in both sexes for the same times. Results showed that the regular food supply caused an increase in the gonadosomatic index in both sexes during all the time periods when compared to the results of animals from the natural environment. We also observed that the females used part of their hepatopancreatic reserves for vitellogenesis and gametogenesis, but the nutrients obtained from the other tissues and the diet were very important for supporting reproduction. Males used the metabolic reserves for growth, gametogenesis, and reproductive behaviors. This study indicates that reproductive events depend on a regular food supply.