Avaliação dos efeitos de uma formulação comercial contendo azadiractina em carpa comum

Abstract

Due to the impact caused by synthetic insecticides in the aquatic environment, natural compounds obtained from natural sources have been used in the attempt of minimizing environmental risks. The commercial product NeenMaxTM, a biopesticide with azadirachtin (Aza) active ingredient, is one of these compounds, utilized in organic agriculture and aquaculture, it has attracted both commercial and research interest. In this sense, the study aimed to investigate the possible behavioral, hematologic, biochemical and histological of the biopesticide NeenMax® effects in various carp tissues (Cyprinus carpio) after 96 h exposure. After a period of acclimation of 10 days in the laboratory, the fish were randomly distributed in 45 L boxes. In article 1, a LC50 was initially determined for carp, estimated at 80 μL/L, thus all further analyses followed the concentrations of 20, 40 and 60 μL/L, corresponding to 25, 50 and 75% of LC50. From the LC50 we investigated behavioral parameters such as travelled distance, absolute turn angle, immobility and immobile episodes through of average and to along 6 minutes. To supplement this study we evaluated a series of hematology parameters, such as red blood count, hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and red cell distribution width. In article 2, we prioritize the assessment on gills because it is a major vital organ of the fish, involved in functions such as respiration and osmoregulation, therefore we evaluated Na+K+-ATPase and assessments related to oxidative stress (reactive substances thiobarbituric acid (TBARS), protein carbonyl (PC), superoxide dismutase (SOD); glutathione S-transferase (GST), catalase (CAT), glutathione peroxidase (GPx), non-protein thiols (NPSH) and ascorbic acid (AsA)), we added the histological analyzes and production of mucus layer (protein and glucose) to supplement our results. In addition in the manuscript, the oxidative stress analyses were performed on the liver, muscle and brain. Thus, we evaluated TBARS, PC, GST, SOD, CAT, NPSH, AsA and AChE. Considering the results obtained, more severe changes were observed in the concentration of 60 μL/L and can highlight changes in motor behavior and locomotion and occurrence of a state of anemia. Nevertheless, the gill system was also impacted by Aza demonstrating inhibition of Na+K+-ATPase and significant histologic changes to the proper functioning of the organ. Still, was observed an increase in the production of glucose and protein, both components of the mucus layer. Thus, the enzymatic antioxidant system and non-enzymatic were also activated in an attempt to detoxify the organism. Through this was possible observe a pattern of more severe damage in proteins than lipids in some organs. Finally, it is important highlight that Aza caused imbalance in the homeostasis of the organism taking into account the concentrations used were sublethal. Thus, further studies with different concentrations and exposure times are necessary for the knowledge of the potential damage that Aza can cause the aquaculture if Aza is used wrongly or empirically.