Publications by authors named "Sharine Descovi"

The objective of this study was to evaluate the possible relaxing effect of essential oils (EOs) (Aloysia triphylla and Lippia alba) and phytochemicals (citral and linalool) in the gastropod Pomacea canaliculata. Animals were exposed to compounds at the concentrations range of 25-750 µL L-1. Magnesium chloride (MgCl2, 10-50 g L-1) and control group (ethanol 6.

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This study aimed to evaluate the essential oil of Ocimum gratissimum L. (EOOG) for anesthesia and in the transport of Oreochromis niloticus. Experiment I determined the time of anesthesia induction and recovery during anesthesia of O.

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Studies using silver catfish (Rhamdia quelen) as experimental models are often applied to screen essential oils (EO) with GABAergic-mediated effects. However, the expression of GABAa receptors in the silver catfish brain remains unknown. Thus, we assessed whether silver catfish express GABAa receptor subunits associated with sedation/anesthetic process and/or neurological diseases.

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Aeromonosis is a fish disease that leads to haemorrhagic septicaemia and high mortality. The detection of early behavioural changes associated to this disease could be helpful in anticipating the initiation of treatment, increasing the probability of success. The influence of this disease on the hypothalamic-pituitary-interrenal (HPI) axis and on the brain expression of heat shock proteins (HSP) is little known.

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This study aimed to evaluate whether dietary supplementation with diphenyl diselenide (PhSe) would prevent the impaired immune and inflammatory responses elicited by methylmercury chloride (CHHgCl) via protective effects on purinergic signaling in fish immune organs. Tissue and lymphocytic nucleoside triphosphate diphosphohydrolase (NTPDase) activity for adenosine triphosphate (ATP) and adenosine diphosphate (ADP) was downregulated in the head kidney and spleen of grass carp (Ctenopharyngodon idella) exposed to CHHgCl. Concomitantly, adenosine deaminase (ADA) activity was upregulated.

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Mycotoxins are secondary metabolites produced by varieties of fungi that contaminate food and feed resources and are capable of inducing a wide range of toxicity. This problem is extensively aggravated due to the increasing replacement of fish meal by plant-derived proteins. Among the mycotoxins, aflatoxins have received a great deal of attention owing to their great prevalence in plant feedstuffs and to the detrimental effects on animals.

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Pseudomonas aeruginosa is a Gram-negative opportunistic bacterial pathogen in aquaculture systems being associated to extensive liver damage caused by oxidative stress in both marine and freshwater fish. Dietary supplementation with natural antioxidants is considered a rational strategy to prevent hepatic diseases involved with oxidative stress. Bio-residues resulting from the wine industry, such as grape pomace, are potential sources of bioactive phenolic compounds that can be applied as supplement for animal production.

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Recent evidence has revealed the involvement of oxidative stress and oxidative damage with health impairment and mortality in fish exposed to hypoxia. Thus, natural compounds with antioxidant and free-radical-scavenging properties, such as caffeine, might help to prevent or reduce hepatic damage elicited by hypoxia. Thus, the aim of this study was to evaluate whether dietary supplementation with caffeine could prevent or reduce oxidative damage in the livers of Nile tilapia (Oreochromis niloticus) exposed to hypoxia.

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The aim of this study was to evaluate whether rupture on blood-brain barrier (BBB) can be a pathway for trichlorfon-induced neurotoxic effects, and to investigate its implications on oxidative status, cell viability and brain neurotransmitters in silver catfish (Rhamdia quelen). The BBB permeability was increased in fish exposed for 24 h to 22 mg/L of trichlorfon compared to the control group, as well as in those exposed to 11 and 22 mg/L of trichlorfon for 48 h. Compared to the control group, brain reactive oxygen species and lipid peroxide levels were higher when exposed to 22 mg/L of trichlorfon and 11 and 22 mg/L of trichlorfon after 24 h and 48 h, respectively, while the antioxidant capacity against peroxyl radical levels was lower.

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Purinergic signaling is linked to neurodegenerative and proinflammatory damage during pathological conditions such as hypoxia, but involvement of this pathway in brain damage in fish exposed to environmental hypoxia remains unknown, and we propose dietary supplementation with caffeine in order to improve the immune response. Therefore, the aim of the study was to evaluate whether the enzymatic purinergic signaling pathway is associated with inflammatory brain damage in Nile tilapia (Oreochromis niloticus) exposed to environmental hypoxia and whether dietary supplementation with caffeine (5% and 8%) can prevent these changes in purinergic signaling. Animals were randomly divided into six groups (A-F, n = 6 per group, in triplicate), as follows: groups A-C were submitted to normoxia, while groups D-F were submitted to hypoxia.

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Recent evidences have suggested the involvement of phosphoryl transfer, catalyzed by creatine kinase (CK), adenylate kinase (AK) and pyruvate kinase (PK), to metabolic alterations and impairment of bioenergetics homeostasis linked to adenosine triphosphate (ATP) production, and utilization during exposure to pesticides. It is recognized that sublethal concentrations of trichlorfon alter hepatic and branchial metabolism, but the pathways involved in this process remains unknown. Thus, the aim of this study was to evaluate whether phosphoryl transfer network can be a pathway involved in the hepatic and branchial metabolic alterations during exposure to sublethal concentrations of trichlorfon using silver catfish Rhamdia quelen as experimental model.

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It has been recognized that oxidative stress is implicated in the initiation and progression of diseases due to the excessive formation of free radicals and impairment of the antioxidant defense system, contributing to the mortality of affected animals. The occurrence of a disequilibrium between the antioxidant/oxidant status in serum and liver of freshwater fish fed with aflatoxin B (AFB) remains poorly understood and limited to only a few oxidant variables. Thus, the aim of this study was to evaluate whether an AFB-contaminated diet causes disturbance on the antioxidant and oxidant status in silver catfish (Rhamdia quelen) of freshwater.

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In teleost fish, stress initiates a hormone cascade along the hypothalamus-pituitary-interrenal (HPI) axis to provoke several physiological reactions in order to maintain homeostasis. In aquaculture, a number of factors induce stress in fish, such as handling and transport, and in order to reduce the consequences of this, the use of anesthetics has been an interesting alternative. Essential oil (EO) of Lippia alba is considered to be a good anesthetic; however, its distinct chemotypes have different side effects.

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The spleen is an important secondary lymphatic organ that plays a key role in the immune and inflammatory responses of teleost fish. The purinergic signalling has been associated to these types of responses under pathological conditions by the regulation of extracellular adenosine triphosphate (ATP) and its metabolite adenosine (Ado), where both exert potent pro-inflammatory and anti-inflammatory profiles, respectively. The exact pathway involved on the immunotoxic effects of aflatoxin B (AFB) in fish fed with diets containing this mycotoxin remains poorly understood.

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Aflatoxin B (AFB) is an environmental toxicant and neurotoxic compound that induces the production of free radicals, causing oxidative stress. Creatine kinase (CK) is a central controller of energy metabolism in tissues with a large and fluctuating energy demand, and it is highly susceptible to inactivation by free radicals and oxidative damage. Thus, the aim of this study was to evaluate whether a diet for freshwater silver catfish (Rhamdia quelen) containing AFB inhibits cerebral CK activity, as well as the involvement of the oxidative stress on this inhibition.

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It is known that the cytotoxic effects of aflatoxin B (AFB) in endothelial cells of the blood-brain barrier (BBB) are associated with behavioral dysfunction. However, the effects of a diet contaminated with AFB on the behavior of silver catfish remain unknown. Thus, the aim of this study was to evaluate whether an AFB-contaminated diet (1177 ppb kg feed) impaired silver catfish behavior, as well as whether disruption of the BBB and alteration of neurotransmitters in brain synaptosomes are involved.

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The phosphotransfer network system, through the enzymes creatine kinase (CK), adenylate kinase (AK), and pyruvate kinase (PK), contributes to efficient intracellular energetic communication between cellular adenosine triphosphate (ATP) consumption and production in tissues with high energetic demand, such as cerebral tissue. Thus, the aim of this study was to evaluate whether aflatoxin B (AFB) intoxication in diet negatively affects the cerebral phosphotransfer network related to impairment of cerebral ATP levels in silver catfish (Rhamdia quelen). Brain cytosolic CK activity decreased in animals fed with a diet contaminated with AFB on days 14 and 21 post-feeding, while mitochondrial CK activity increased, when compared to the control group (basal diet).

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The antibiotics were frequently used for combating bacterial infections in aquaculture, but this treatment causes antibiotic resistance, negative impact on the environment and on health, and accumulation of residual in edible tissues. Several evidences have considered the dietary supplementation with natural products an interesting alternative to antibiotics, as the use of curcumin, a polyphenol with anti-inflammatory, antioxidant and antimicrobial properties. Thus, the aim of this study was to evaluate whether fish fed with a diet containing 150 mg curcumin/kg feed is able to enhance the resistance of silver catfish to Streptococcus agalactiae infection.

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