869 resultados para FISH OIL
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10 x 15 cm
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kuv., 20 x 30 cm
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kuv., 20 x 30 cm
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kuv., 20 x 30 cm
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kuv., 20 x 28 cm
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kuv., 14 x 22 cm
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kuv., 10 x 15 cm
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kuv., 10 x 15 cm
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Thousands of tons of pharmaceuticals are consumed yearly worldwide. Due to the continuous and increasing consumption and their incomplete elimination in wastewater treatment plants (WWTP), pharmaceuticals and their metabolites can be detected in receiving waters, although at low concentrations (ng to low μg/L). As bioactive molecules the presence of pharmaceuticals in the aquatic environment must be considered potentially hazardous for the aquatic organisms. In this thesis, the biotransformation and excretion of pharmaceuticals in fish was studied. The main biotransformation pathways of three anti‐inflammatory drugs, diclofenac, naproxen and ibuprofen, in rainbow trout were glucuronidation and taurine conjugation of the parent compounds and their phase I metabolites. The same metabolites were present in fish bile in aquatic exposures as in fish dosed with intraperitoneal injection. Higher bioconcentration factor in bile (BCFbile) was found for ibuprofen when compared to diclofenac and naproxen. Laboratory exposure studies were followed by a study of uptake of pharmaceuticals in a wild fish population living in lake contaminated with WWTP effluents. Of the analyzed 17 pharmaceuticals and six phase I metabolites, only diclofenac, naproxen and ibuprofen was present in bream and roach bile. It was shown, that diclofenac, naproxen and ibuprofen excreted by the liver can be found in rainbow trout and in two native fish species living in the receiving waters. In the bream and roach bile, the concentrations of diclofenac, naproxen and ibuprofen were roughly 1000 times higher than those found in the lake water, while in the laboratory exposures, the bioconcentration of the compounds and their metabolites in rainbow trout bile were at the same level as in wild fish or an order of magnitude higher. Thus, the parent compounds and their metabolites in fish bile can be used as a reliable biomarker to monitor the exposure of fish to environmental pharmaceuticals present in water receiving discharges from WWTPs.
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Multiple factors can be involved in the virulence processes of Aeromonas hydrophila. The objective of the present paper was to verify the presence of aerolysin, hidrolipase, elastase and lipase virulence genes through the polymerase chain reaction (PCR) in A. hydrophila isolates obtained from fish of the São Francisco River Valley, and to evaluate virulence according to the presence of these genes in Nile tilapia fingerlings. One hundred and fourteen isolates from the bacteria were used. DNA was heat extracted and PCR undertaken using specific primers described in the literature. For in vivo tests Nile tilapia fingerlings were used. From the PCR tests, negative isolates for all genes tested were selected, positive isolates for two genes (aerolysin and elastase) and positive for the four genes tested. These were inoculated at a concentration of 10(8) UFC/ml into the tilapias, considered as treatments; another group of animals was used as control (with inoculation of saline solution). In all, 12 distinct standards regarding the presence of virulence factors in isolates from A. hydrophila, were observed. Of the 114 isolates analyzed, 100 (87.72%) presented at least one of the virulence factors under study. The virulence factors were widely distributed among the A. hydrophila isolates. Aerolysin was the most frequent virulence factor present in the isolates analyzed. A. hydrophila led to the mortality of the Nile tilapia fingerlings, regardless of the absence or quantity of virulence genes tested.
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This paper presents a science metric study of parasites of fish farming in Brazil, including a significant review of the literature. The methodology used was based on researching articles in three different databases, carried out on May 2012: ISI (Institute for Scientific Information), SciELO (Scientific Electronic Library Online), and Google Academic. The number of articles on fish parasites is mounting (currently over 110), having much increased since 1995. However, the quantity is still low compared with the amount of papers on parasites of fish from natural environments. In Brazil, the farmed fish that have been studied the most are pacu, tilapia and tambaqui. Monogeneans represent the most prevalent group, followed by protozoa and crustaceans. The regions most researched were the southeast and south, making up 84% of the total literature. The main issue addressed in articles was pathology, followed by treatment and record. In conclusion, the treatment of parasitic diseases of farmed fish in Brazil is still incipient, highlighting the importance and usefulness of management practices to prevent the occurrence of health problems.
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The 2,4-dichlorophenoxyacetic acid, usually named 2,4-D is one of the most widely used herbicides in the world. Acute toxicity of 2,4-D herbicide was investigated through its effects on guppies (Poecilia vivipara Bloch et Schneider 1801). Fish were exposed to the herbicide at concentrations of 10, 20 and 40µl per liter of water for 24 hours to determine its effects on gills and liver epithelia. The estimated LC50 was 34.64µl of 2,4-D per liter of water. Histochemical analyses and Feulgen's reaction were conducted to detect glycoconjugates and DNA, respectively, in gills and liver epithelia. Histochemistry revealed qualitative variations of glycoconjugates present on mucous cells and granules. The four types of mucous cells contained neutral granules, acids, or both. Increasing amounts of syalomucins were observed from the control group to the group exposed to the highest concentration of 2,4-D, suggesting increased mucous viscosity and the formation of plaques that could inhibit gas exchange and osmoregulation. Lamellar fusion observed in the group exposed to 40µl of 2,4-D suggests a defense mechanism. Hepatocytes showed vacuolization in the 10 and 20µl/L groups. The 40 µl/L group showed normal hepatocytes as well as changed ones, many Ito cells, micronuclei, and nuclear swelling. These effects may be associated with toxicity or adaptative processes to cellular stress. The data from this study indicates the importance of assessing similar risks to aquatic species and suggests that Poecilia vivipara is an adequate biological model for analysis of environmental contamination.
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Currently, there is a growing interest in medicinal plants, because of an increased demand for alternate therapies. In this study, the antimicrobial activity and toxicity of the essential oil of Lippia origanoides (L. origanoides) were investigated. The essential oil of L. origanoides was extracted by steam-dragging distillation and its constituents were identified by chromatography coupled with mass spectrometry. Among the 15 compounds identified, the most abundant were carvacrol (29.00%), o-cymene (25.57%), and thymol methyl ether (11.50%). The essential oil was studied in antimicrobial assays to determine the MIC and MBC. The results indicated that a concentration of 120μL/mL of oil was sufficient to inhibit the growth of the following microorganisms: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Salmonella cholerasuis (ATCC 10708). Acute and chronic toxic effects of orally administered oil were investigated in Wistar rats by using standard methods. Doses of 30, 60 and 120mg/kg of the essential oil did not induce significant changes in weight, behavior or hematological and biochemical parameters in the animals. There were no signs of any histopathological changes to the liver, kidneys or heart of the treated rats, suggesting that Lippia origanoides oil is non-toxic after oral administration in acute or chronic toxicity studies. The results obtained in this study show that the essential oil of L. origanoides has a high safety margin, with no detectable toxic effects in rats treated with doses to 120mg/kg. In addition, L. origanoides oil demonstrated potent antimicrobial activity against S. aureus, E. coli and S. cholerasuis. Based on these findings, this essential oil may have practical application as a veterinary antimicrobial.
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This paper presents an ultrasonic method to measure small concentrations of water in lubricating oil. It uses an ultrasonic measurement cell composed by a piezoceramic emitter (5 and 10 MHz), and a large aperture PVDF receiver that eliminates diffraction effects. The propagation velocity, attenuation coefficient and density of several samples of water-in-oil emulsion were measured. The concentrations of water of the samples were in the range of 0 to 5% in volume, and the results showed that these low concentrations can be discriminated within a resolution of 0.2% in the studied range, using the measurement of the propagation velocity.