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Aiming to study the changes in the diet of Astyanax altiparanae in the early developmental stages, in the presence of Eichhornia crassipes (EC) and Lemna sp. (LM), larvae of Astyanax altiparanae were stocked in eight tanks of 900 L (500 ind. tank-1), four with EC and four with LM covering 50% surface. Tanks were inoculated with plankton and received 3.0 g inorganic fertilizer (NPK-7:14:8) and 1.5 g every week. At every three days, three larvae were taken from each tank, fixed in 4% formaldehyde and grouped into four age classes (I: 6 to 12 days, II:15 to 21 days, III:24 to 30 days; IV:33 to 39 days). The analysis of dominance and frequency of occurrence (FO) of food items indicated that, at this stage, A. altiparanae is generalist. In class I, there was a greater dominance and FO of Lecane bulla and Alona sp. in digestive tracts in the presence of both EC and LM, respectively; and larvae started to consume larger organisms, such as Chironomidae, in other age classes with EC. In the presence of LM, Alona sp. was dominant in class II; Chironomidae, in class III and Centropyxis sp., in class IV. Diatoms have greater FO both in EC and in LM. In class III, with EC, Chironomidae had higher FO, as well as Arcella sp. and Scenedesmus spp. with LM. The highest FO in class IV was found for L. bulla and Scenedesmus spp., with EC and LM, respectively. It can be concluded that EC and LM influenced the diet of Astyanax altiparanae, with alterations according to the availability of organisms and increase in age.

Made available in DSpace on 2022-04-29T11:52:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-01 The aim of this study was to estimate copper sulfate acute toxicity and to determine death percentage and environmental risk on guppy fish (Phallocerus caudimaculatus), zebrafish (Brachydanio rerio), mato grosso (Hyphessobrycon eques), and pacu (Piaractus mesopotamicus). Fish were exposed to 0.01, 0.03, 0.05, 0.07, 0.10, and 0.30 mg L-1(guppy), 0.05, 0.07, 0.10, and 0.30 mg L-1(zebrafish), 0.07, 0.10, 0.20, and 0.30 mg L-1(mato grosso) and 9.5, 10.0, 10.5, 11.0, 11.5, and 12.0 mg L-1(pacu) of copper sulfate, with triplicate control. The estimated 50% average lethal concentrations (LC50; 96 hours) were 0.05 (guppy), 0.13 (zebrafish); 0.16 (mato grosso) and 10.36 mg L-1(pacu). Copper sulfate was extremely toxic for guppy, highly toxic for zebrafish and mato grosso and lightly toxic for pacu and presents environmental risk of high adverse effects on the guppy, zebrafish and mato grosso and moderate adverse effect to the pacu. Therefore, the guppy fish, zebrafish, and mato grosso are important alternatives for copper sulfate toxicity evaluation in waterbodies. Núcleo de Estudos e Pesquisas Ambientais em Matologia Universidade Estadual Paulista ‘Júlio de Mesquita Filho’, Via de acesso Paulo Donato Castellane, s/n Núcleo de Estudos e Pesquisas Ambientais em Matologia Universidade Estadual Paulista ‘Júlio de Mesquita Filho’, Via de acesso Paulo Donato Castellane, s/n

Effect of larvae of Astyanax altiparanae (AA), Piaractus mesopotamicus (PM), Leporinus obtusidens (LO) and Prochilodus lineatus (PL) on plankton communities and water quality were evaluated. Twenty 500 L tanks were used into a completely randomized design with five treatments and four replications, containing 350 individuals of each species per tank. One treatment control had no larvae (CT). Every six days, were collected periphyton and water to determine the concentrations of chlorophyll and total phosphorus. Plankton samples (20 mm mesh net) were taken every three days. Fish affected plankton communities, which showed lower densities of total zooplankton in AA tanks than in LO tanks. Increased density of rotifers and reduced density of copepods were found in AA, PM and PL tanks in relation to the CT. Higher density of testate amoebae was observed in AA, PM and LO tanks. As to biovolume, higher values for total plankton were registered in the CT and LO tanks compared with AA, PM and PL tanks; higher values for rotifers were observed in PL tanks than in the CT. Copepod biovolume was higher in CT and LO tanks. Biovolume of cladoceran and testate amoebae were not affected. Plankton´s chlorophyll concentration was higher in tanks with fish. Higher concentrations of dissolved oxygen were found in AA and PM tanks. It can be concluded that juveniles of these fish species differently affect the plankton community and chemical parameters of the water.

Natural insecticides derived from plant extracts have been used as an alternative to synthetic products in order to reduce environmental contamination. The present study aimed to examine the effects of Fumydro®, a natural insecticide based in the tobacco plant Nicotiana tabacum, on the Nile tilapia (Oreochromis niloticus) by determining the 48-h LC50 and evaluating their effects on hematological variables. Adult specimens of O. niloticus were exposed to four Fumydro® concentrations (200, 300, 400 and 500 μL L-1). The 48-h LC50 of Fumydro® was determined as 370 ± 50 μL L-1. Surviving fish showed increasing in the red blood cells, hemoglobin concentration, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The thrombocytes did not change but the percentage of neutrophils increased. These results indicated that the insecticide Fumydro® is toxic to Nile tilapia and the changes of the erythrocyte variables suggested hypoxemia induction with low effect on the immune system. Natural insecticides from plant extracts represent an alternative to the highly toxic synthetic products in order to reduce environmental contamination; however some might also be toxic for non-target organisms. The present study determined the 50% lethal concentration (48h; LC50) for adults Nile tilapia (Oreochromis niloticus) exposed to the natural insecticide Fumydro®, based on the tobacco plant (Nicotiana tabacum), and evaluated its effect on hematological variables. After preliminary tests, adult specimens of O. niloticus were exposed to four Fumydro® concentrations (200, 300, 400 and 500 μL L-1). The 48h; LC50 of Fumydro® was determined at 370 ± 50 μL L-1. The surviving fish after exposure to Fumydro® showed an increase in the number of red blood cells, hemoglobin concentration, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The number of thrombocytes and leukocytes has not changed, unlike the differential leukocyte count that presented an increased percentage of neutrophils. The results indicated that the insecticide Fumydro® is highly toxic to Nile tilapia and changes in erythrocyte variables suggested the induction to hypoxemia with low effect on the immune system.

A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12) and in two alternative culture media, NPK (20-5-20) and macrophyte (Eichhornia crassipes) + NPK, in three different types of recipients (fiberglass, carboy and plastic bag). First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1) in a fiberglass recipient. However, highest density (p < 0.01) was reported in medium CHU12 (122.87 x 105 cells mL-1) in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05) in culture media in the three recipients. Protein and fiber were similar (p > 0.05) in the treatments, but lipids were higher (p < 0.05) in NPK. Nitrate, ammonia, total phosphorus and orthophosphate contents were over 1 mg L-1 in NPK (p < 0.01). Results show that alternative media, such as NPK and macrophyte + NPK, are possible for large-scale culture of A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the laboratory. A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12) and in two alternative culture media, NPK (20-5-20) and macrophyte (Eichhornia crassipes) + NPK, in three different types of recipients (fiberglass, carboy and plastic bag). First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1) in a fiberglass recipient. However, highest density (p < 0.01) was reported in medium CHU12 (122.87 x 105 cells mL-1) in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05) in culture media in the three recipients. Protein and fiber were similar (p > 0.05) in the treatments, but lipids were higher (p < 0.05) in NPK. Nitrate, ammonia, total phosphorus and orthophosphate contents were over 1 mg L-1 in NPK (p < 0.01). Results show that alternative media, such as NPK and macrophyte + NPK, are possible for large-scale culture of A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the laboratory.