RESUMO
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 6.75 mL L-1, highest concentration used for treatment dilution) were also tested. The EOs, citral and MgCl2 had no relaxing effect at the concentrations range tested, and citral caused aversive behavior (closure of the operculum) from 90 µL L-1. Exposure to linalool at 25, 50, 100, 200 and 400 µL L-1 relaxed 28, 76, 88, 96 and 100% of the animals, respectively. The concentrations of 25, 50 and 400 µL L-1 differed statistically from each other, while 100 and 200 µL L-1 were equal to 50 and 400 µL L-1. All animals recovered up to 40 min, except at of 400 µL L-1. Linalool is effective for relaxing P. canaliculata and can be useful in management techniques that require relaxation. However, further studies are needed to certify whether linalool is appropriate for maintaining animal welfare in invasive procedures that require total insensitivity.
Assuntos
Monoterpenos Acíclicos/farmacologia , Lippia , Caramujos/efeitos dos fármacos , Verbenaceae , AnimaisRESUMO
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. Additionally, we evaluated the brain expression of GABAa receptor subunits in fish sedated with Nectandra grandiflora EO and its isolated compounds, the fish anesthetic (+)-dehydrofukinone (DHF), and dehydrofukinone epoxide (DFX), eremophil-11-en-10-ol (ERM) and selin-11-en-4-α-ol (SEL), which have GABAa-mediated anxiolytic-like effects in mice. The expression of the subunits gabra1, gabra2, gabra3, gabrb1, gabrd and gabrg2 in the silver catfish brain were assessed after a 24h-sedation bath by real time PCR. Since qPCR data rarely describes mechanisms of action, which are usually found through interactions with receptors, we also performed an antagonist-driven experiment using flumazenil (FMZ). Real-time PCR detected the mRNA expression of all targeted genes in R. quelen brain. The expression of gabra1 was decreased in fish sedated with ERM; EO increased gabra2, gabra3, gabrb1 and gabrg2 expression; SEL increased gabrb1, gabrd and gabrg2 expression. EO and compounds DFX, SEL and ERM induced sustained sedation in fish and FMZ-bath prompted the recovery from ERM- and DFX-induced sedation. Our results suggest that the EO, SEL, ERM and DFX sedative effects involve interaction with the GABAergic system. Our findings support the use of the silver catfish as robust and reliable experimental model to evaluate the efficacy of drugs with putative GABAergic-mediated effects.
Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Proteínas de Peixes/metabolismo , GABAérgicos/farmacologia , Óleos Voláteis/farmacologia , Receptores de GABA-A/metabolismo , Animais , Peixes-Gato , GABAérgicos/isolamento & purificação , Expressão Gênica/efeitos dos fármacos , Hipnóticos e Sedativos/isolamento & purificação , Hipnóticos e Sedativos/farmacologia , Lauraceae , Óleos Voláteis/isolamento & purificação , Folhas de Planta , RNA Mensageiro/metabolismoRESUMO
This study aimed to evaluate whether dietary supplementation with diphenyl diselenide (Ph2Se2) would prevent the impaired immune and inflammatory responses elicited by methylmercury chloride (CH3HgCl) 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 CH3HgCl. Concomitantly, adenosine deaminase (ADA) activity was upregulated. Further, nucleotide-binding oligomerization domain-like receptor (NLRP3) inflammasome gene expression was upregulated in the spleen and head kidney of CH3HgCl-exposed grass carp. Dietary supplementation with Ph2Se2 ameliorated these CH3HgCl-mediated alterations on purinergic enzymes, and their activities returned to baseline levels (except NTPDase activity for ADP). Based on these results, purinergic signaling in immune organs and lymphocytes can be considered a pathway linked to pro-inflammatory effects during exposure to environmental CH3HgCl concentrations, which may contribute to mortality of the affected fish. Since dietary supplementation with 3â¯mg Ph2Se2/kg in the feed prevented the CH3HgCl-induced alterations, it can be considered a potential suitable treatment to prevent impaired immune and inflammatory responses caused by Hg.
Assuntos
Derivados de Benzeno/farmacologia , Carpas , Doenças dos Peixes/induzido quimicamente , Rim Cefálico/efeitos dos fármacos , Compostos de Metilmercúrio/toxicidade , Compostos Organosselênicos/farmacologia , Baço/efeitos dos fármacos , Ração Animal/análise , Animais , Dieta/veterinária , Suplementos Nutricionais , Doenças dos Peixes/prevenção & controle , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamassomos/efeitos dos fármacos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Substâncias Protetoras/farmacologia , Transdução de SinaisRESUMO
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. Hepatic reactive oxygen species, lipid peroxidation levels, and xanthine oxidase (XO) activity were higher in fish exposed to hypoxia compared with normoxia. Hepatic catalase, glutathione peroxidase, and glutathione S-transferase activities, as well as the antioxidant capacity against peroxyl radical levels, were lower in fish exposed to hypoxia compared with normoxia. No significant difference between groups was observed regarding hepatic superoxide dismutase activity. Dietary supplementation with 8% caffeine prevented all alterations elicited by hypoxia. Based on this evidence, the use of dietary supplementation with 8% caffeine can be an interesting approach to preventing hepatic lipid damage and impairment of the antioxidant defense system elicited by hypoxia, and this effect can be mediated by protective effects on XO activity.
Assuntos
Cafeína/farmacologia , Ciclídeos , Dieta/veterinária , Suplementos Nutricionais , Hepatopatias/veterinária , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Biomarcadores , Cafeína/administração & dosagem , Catalase/metabolismo , Estimulantes do Sistema Nervoso Central/administração & dosagem , Estimulantes do Sistema Nervoso Central/farmacologia , Relação Dose-Resposta a Droga , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos , Fígado/enzimologia , Hepatopatias/etiologia , Hepatopatias/prevenção & controle , Estresse Oxidativo , Peróxidos , Espécies Reativas de Oxigênio , Superóxido Dismutase/metabolismoRESUMO
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. Thus, the aim of this study was to evaluate whether dietary supplementation with grape pomace flour (GPF) was able to prevent or reduce the hepatic oxidative damage of grass carp, Ctenopharyngodon idella, experimentally infected by P. aeruginosa. Hepatic reactive oxygen species (ROS), metabolites of nitric oxide (NOx), thiobarbituric acid reactive substances, and protein carbonylation levels were higher in fish experimentally infected by P. aeruginosa compared to the control group. Hepatic superoxide dismutase and catalase activities and antioxidant capacity against peroxyl radical levels were also higher in fish experimentally infected by P. aeruginosa compared to the control group. Dietary supplementation with 300â¯mg/kg GPF prevented all alterations elicited by P. aeruginosa, with the exception of protein carbonylation levels. The dietary supplementation with 150â¯mg/kg GPF was not able to avoid alteration of the analyzed variables, being results similar to those infected (positive control). Based on these results, dietary supplementation with 300â¯mg/kg GPF prevented P. aeruginosa-induced liver damage in grass carp, and this protective effect occurred through prevention on excessive ROS and NOx production, as well as via prevention of lipid damage. Moreover, 300â¯mg/kg GPF exerted its hepatoprotective effects by improving enzymatic and non-enzymatic antioxidant defense system. In summary, this supplementation can be an interesting approach to prevent P. aeruginosa-induced liver damage.
Assuntos
Antioxidantes/administração & dosagem , Dietoterapia/métodos , Doenças dos Peixes/terapia , Hepatopatias/veterinária , Estresse Oxidativo , Infecções por Pseudomonas/veterinária , Vitis/química , Animais , Carpas , Catalase/análise , Doenças dos Peixes/patologia , Farinha , Hepatopatias/patologia , Hepatopatias/terapia , Óxido Nítrico/análise , Carbonilação Proteica , Infecções por Pseudomonas/patologia , Infecções por Pseudomonas/terapia , Espécies Reativas de Oxigênio/análise , Superóxido Dismutase/análise , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Resultado do TratamentoRESUMO
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. Groups A and D received the basal diet, while groups B and D and groups C and F received a diet containing 5% and 8% caffeine, respectively, and fed with their respective diets for 21 days. After 21 days, aeration was disconnected (groups D-F) and the dissolved oxygen levels were maintained as follows: group A (6.55 ± 0.23 mg/L), group B (6.51 ± 0.24 mg/L), group C (6.58 ± 0.22 mg/L), group D (1.23 ± 0.11 mg/L), group E (1.20 ± 0.15 mg/L), and group F (1.18 ± 0.13 mg/L). Cerebral triphosphate diphosphohydrolase (NTPDase) using adenosine triphosphate (ATP) as a substrate and 5'-nucleotidase activities decreased in fish exposed to 72 h of hypoxia compared with the normoxia group, while adenosine deaminase (ADA) activity and levels of nitric oxide (NOx) metabolites were higher. Dietary supplementation with 5% and 8% caffeine prevented all alterations elicited by hypoxia, with the exception of ADA activity in the case of 5% caffeine. Based on this evidence, our findings reveal that nucleotide/nucleoside hydrolysis is modified in the brains of fish exposed to 72 h of hypoxia, contributing to inflammatory damage, which apparently is mediated by excessive ATP content in the extracellular medium and by excessive NOx production. Also, the use of a diet containing 5% and 8% caffeine prevented these alterations (except 5% of dietary caffeine on ADA activity) and can be considered an interesting approach to preventing the impairment of immune and inflammatory responses elicited by hypoxia, principally the inclusion of 8% caffeine.