Efeitos do óleo de cravo no comportamento da tilápia do nilo
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Data
2020-06-05
Autores
Silva, Dneson Ricardo
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Universidade Estadual Paulista (Unesp)
Resumo
Óleos essenciais com efeitos sedativos vêm sendo usados como potenciais substitutos de anestésicos sintéticos. Nessa linha, o óleo extraído de partes da planta do cravo da Índia (Eugenia caryophyllata)vem ganhando notoriedade como anestésico. Esse óleo vem sendo considerado eficaz, pois induz anestesia rapidamente, e também seguro, pois a recuperação dos reflexos é breve e ocorre baixa mortalidade. Entretanto, não se sabe se há modificações na reatividade a estímulos relevantes e nem se afeta os componentes motivacionais do comportamento. Como os efeitos dos anestésicos se dão no sistema nervoso, é plausível supor tais possibilidades. Neste estudo, utilizando a tilápia-do-Nilo (linhagem Supreme, revertidas sexualmente), um peixe altamente relevante para aquicultura mundial, testamos essa hipótese mencionada anteriormente. Operacionalmente, mensuramos elementos dos comportamentos alimentar e agressivo como meio para inferirmos efeitos na reatividade a estímulos e na motivação. Para isso, utilizando a técnica da exposição em banho, submetemos os peixes a 3 condições diferentes (n = 12 cada): 1) controle negativo (sem anestésico) e duas soluções alcoólica de óleo de cravo diluído em água2) 50mg/L e 3) 100 mg/L. As tilápias foram selecionadas aleatoriamente, removidas do tanque de estoque e inseridas isoladas em banho de solução anestésica em baldes plásticos atóxicos até atingirem o estágio II de anestesia (perda de equilíbrio e reflexo, pouco ou nenhum movimento muscular, mas manutenção das batidas operculares). Quantificamos o tempo para atingir esse estágio e, assim que atingido, os peixes foram removidos do banho e introduzidos em aquários (1 peixe por aquário) para futuras observações do comportamento. Os peixes controle (0 mg/L) foram expostos aos mesmos procedimentos e permaneceram nos baldes até o maior intervalo de tempo para um dos peixes da bateria atingir o estágio II de anestesia. As tilápias foram mantidas nos aquários por 4 dias consecutivos e, enquanto o comportamento alimentar foi avaliado diariamente, o agressivo foi avaliado no segundo e no quarto dia.Nossas evidências indicam que o óleo de cravo não afetou os componentes consumatórios e apetitivos dos comportamentos avaliados. Assim, nossos resultados reforçam o uso seguro de óleo de cravo-da-índia em práticas de aquicultura que requerem anestesia em tilápias.
Essential oils with sedative effects have been used as potential substitutes for synthetic anesthetics in aquaculture. In this context, the oil extracted from parts of the clove plant (Eugeniacaryophyllata) has been gaining notoriety as anesthetic. This oil has been considered effective, because it induces anesthesia quickly, reflex recovery is brief and has low mortality rate. However, it is unknown whether there are changes in stimuli reactivity and behavioral motivational in fish after anesthesia recovery. As the effects of anesthetics are on the central nervous system, it is plausible to assume such possibilities. In this study, using Nile tilapia (Supreme lineage, sexually reversed), a highly relevant fish for world aquaculture, we tested this hypothesis. Operationally, we measured elements of feeding and aggressive behaviors to infer effects on reactivity to stimuli and motivation. For this, using the bath exposure technique, we submitted the fish to 3 different conditions (n = 12 each): 1) negative control (without anesthetic) and two alcoholic solutions of clove oil diluted in water 2) 50mg / L and 3) 100 mg / L. Tilapia were randomly selected, captured from the stock tank and placed isolated in bath of anesthetic solution until they reach stage II of anesthesia (loss of balance and reflex, fewor no muscle movement, but maintenance of opercular beats). We quantified the time to reach this stage and, once reached, the fish were removed from the bath and introduced into test aquaria forbehavior observation. Control fish were exposed to the same procedures and remained into the solutionuntil the longest period for one of the fish in the batch to reach stage II of anesthesia. Tilapia were kept in the aquaria for 4 consecutive days. We evaluated feeding behavior daily and aggressive behavior on the second and fourth days. Our evidencesshowthat clove oil did not affect reactivity to stimuli and motivation regarding these evaluated behaviors. Thus, our results reinforce the safe use of clove oil in aquaculture practices that require anesthesia in fish.
Essential oils with sedative effects have been used as potential substitutes for synthetic anesthetics in aquaculture. In this context, the oil extracted from parts of the clove plant (Eugeniacaryophyllata) has been gaining notoriety as anesthetic. This oil has been considered effective, because it induces anesthesia quickly, reflex recovery is brief and has low mortality rate. However, it is unknown whether there are changes in stimuli reactivity and behavioral motivational in fish after anesthesia recovery. As the effects of anesthetics are on the central nervous system, it is plausible to assume such possibilities. In this study, using Nile tilapia (Supreme lineage, sexually reversed), a highly relevant fish for world aquaculture, we tested this hypothesis. Operationally, we measured elements of feeding and aggressive behaviors to infer effects on reactivity to stimuli and motivation. For this, using the bath exposure technique, we submitted the fish to 3 different conditions (n = 12 each): 1) negative control (without anesthetic) and two alcoholic solutions of clove oil diluted in water 2) 50mg / L and 3) 100 mg / L. Tilapia were randomly selected, captured from the stock tank and placed isolated in bath of anesthetic solution until they reach stage II of anesthesia (loss of balance and reflex, fewor no muscle movement, but maintenance of opercular beats). We quantified the time to reach this stage and, once reached, the fish were removed from the bath and introduced into test aquaria forbehavior observation. Control fish were exposed to the same procedures and remained into the solutionuntil the longest period for one of the fish in the batch to reach stage II of anesthesia. Tilapia were kept in the aquaria for 4 consecutive days. We evaluated feeding behavior daily and aggressive behavior on the second and fourth days. Our evidencesshowthat clove oil did not affect reactivity to stimuli and motivation regarding these evaluated behaviors. Thus, our results reinforce the safe use of clove oil in aquaculture practices that require anesthesia in fish.
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Palavras-chave
Óleo de cravo, Anestesia, Estresse, Bem-estar, Comportamento alimentar, Agressão