Rodlet cells changes in Oreochromis niloticus in response to organophosphate pesticide and their relevance as stress biomarker in teleost fishes

Rodlet cells are frequently found in teleost fishes and although their role in organisms is not completely understood. The occurrence of these cells are related to stress and may undergo changes in contaminated environments, thereby allowing their use as biomarkers. This hypothesis is tested in the present study. Thirty specimens of Oreochromis niloticus were divided into three groups, two groups were exposed to organophosphate pesticide methyl parathion at nominal concentrations of 4 mgl-1 and 8 mgl-1 and one group was kept as control. After ten days, the gills were removed for microscopic study and the number and area of the rodlet cells were analyzed and compared with a well-established method of assessing histological damages in fishes. No significant differences were found in the area of the cells, but there were significant differences in the number of rodlet cells among examined concentrations. The present study provides evidence for the use of this new biomarker in teleost fishes and discusses some of the potential confounding factors of this approach

Rodlet cells changes in Oreochromis niloticus in response to organophosphate pesticide and their relevance as stress biomarker in teleost fishes

Rodlet cells are frequently found in teleost fishes and although their role in organisms is not completely understood. The occurrence of these cells are related to stress and may undergo changes in contaminated environments, thereby allowing their use as biomarkers. This hypothesis is tested in the present study. Thirty specimens of Oreochromis niloticus were divided into three groups, two groups were exposed to organophosphate pesticide methyl parathion at nominal concentrations of 4 mgl-1 and 8 mgl-1 and one group was kept as control. After ten days, the gills were removed for microscopic study and the number and area of the rodlet cells were analyzed and compared with a well-established method of assessing histological damages in fishes. No significant differences were found in the area of the cells, but there were significant differences in the number of rodlet cells among examined concentrations. The present study provides evidence for the use of this new biomarker in teleost fishes and discusses some of the potential confounding factors of this approach

Lipidic and proteic absorption in digestive tract of tropical fat snook (Centropomus parallelus, POEY 1860)

The tropical fat snook Centropomus parallelus is a species of recognized ecological importance and with a high economical potential for fisheries and aquaculture. The investigations of digestive tube morphology in association with their feeding abilities are fundamental to improve techniques for aquaculture feeding procedures. Sudan black staining and Perl`s method were used to evaluate their absorption capacity of fat and protein respectively. The Sudan black stain was performed 12 h after the ingestion of lipids. The lipids are intensely absorbed in the ceca epithelium and less intensely in the intestine and rectum. The Perl`s method was performed 12 h after the ingestion of ferritin. The proteins are absorbed only in the rectum. This is the first description of fat and protein absorption ability by the digestive tube of fat snook. These data enhance the possibility of the addition of macromolecules in rations that can show a diversity of physiological effects. The histological implications of each segment of the digestive tube in association with fish biology are further discussed. (C) 2010 Elsevier B.V. All rights reserved.Faculdades Metropolitanas Unidas - FMUFaculdades Metropolitanas Unidas - FM