Basil, tea tree and clove essential oils as analgesics and anaesthetics in Amphiprion clarkii (Bennett, 1830) / Óleos essenciais de manjericão, melaleuca e cravo como anestésicos e analgésicos em Amphiprion clarkii (Bennett, 1830)

Abstract In this study were evaluated the anaesthesia and analgesic effects of clove Eugenia caryophyllata, tea tree Melaleuca alternifolia and basil Ocimum basilicum essential oils (EO) during handling of yellowtail clownfish Amphiprion clarkii. Juveniles (3.70 ± 0.75 cm and 1.03 ± 0.50 g; mean ± standard deviation) were submitted to concentrations of 40, 50, 60, 70 and 80 µl L-1 of clove, 150, 200, 250, 300 and 350 µl L-1 of basil and 200, 300, 400, 500 and 600 µl L-1 of tea tree oils (n=10/concentration), previously defined in pilot tests. Individually and only once, fish from each treatment were placed in a glass recipient containing 1 L of seawater at a temperature of 25 °C, salinity of 35 g L-1 and the specific concentration of diluted EO (stock solution). Control (only seawater) and blank (seawater and ethanol at the highest concentration used to dilute the oils) treatments were also conducted. After reaching the stage of surgical anaesthesia, fish were submitted to biometry and a sensibility test. After that, they were transferred to clean seawater for anaesthesia recovery. The times of induction needed to reach each anaesthesia stage and anaesthesia recovery were recorded. Animals were observed for 72 hours after the procedures. All the EO provoked anaesthesia and analgesic effects in A. clarkii, but basil oil is not recommended because it caused involuntary muscle contractions and mortality in 100% and 12% of fish, respectively. The lower concentrations that promote suitable induction and recovery times are 50 µl L-1 of clove oil and 500 µl L-1 of tea tree oil. However, due to its complementary high analgesic efficiency, clove oil is recommended as the ideal anaesthetic for A. clarkii.

Resumo Neste estudo foram avaliados os efeitos anestésicos e analgésicos dos óleos essenciais (OE) de cravo Eugenia caryophyllata, melaleuca Melaleuca alternifolia e manjericão Ocimum basilicum durante manejo de peixes-palhaços Amphiprion clarkii. Juvenis (3.70 ± 0.75 cm e 1.03 ± 0.50 g; média ± desvio padrão) foram submetidos às concentrações de 40, 50, 60, 70 e 80 µl L-1 de cravo, 150, 200, 250, 300 e 350 µl L-1 de manjericão e 200, 300, 400, 500 e 600 µl L-1 de melaleuca (n=10/concentração), previamente definidas em testes pilotos. Individualmente e somente uma vez, os peixes de cada tratamento foram colocados em recipiente de vidro contendo 1 L de água salgada, em temperatura de 25 °C, salinidade de 35 g L-1 e a concentração específica de OE diluída (solução estoque). Tratamentos controle (apenas água marinha) e branco (água marinha e a maior concentração de etanol utilizada para diluição dos óleos) também foram conduzidos. Após atingirem o estágio de anestesia cirúrgica, os peixes foram submetidos à biometria e teste de sensibilidade. Em seguida, foram transferidos para água marinha limpa. Os tempos necessários para atingir cada estágio anestésico e recuperação foram registrados. Os animais foram observados por 72 horas após os procedimentos. Todos os OE provocaram anestesia e analgesia em A. clarkii, porém o óleo de manjericão não é recomendado, pois causou contrações musculares involuntárias e mortalidade em 100% e 12% dos animais, respectivamente. As menores concentrações que promovem indução anestésica e recuperação em tempos adequados são 50 µl L-1 de óleo de cravo e 500 µl L-1 de óleo de melaleuca. Entretanto, devido à sua alta eficiência analgésica complementar, o óleo de cravo é recomendado como o anestésico ideal para A. clarkii.

Basil, tea tree and clove essential oils as analgesics and anaesthetics in Amphiprion clarkii (Bennett, 1830).

In this study were evaluated the anaesthesia and analgesic effects of clove Eugenia caryophyllata, tea tree Melaleuca alternifolia and basil Ocimum basilicum essential oils (EO) during handling of yellowtail clownfish Amphiprion clarkii. Juveniles (3.70 ± 0.75 cm and 1.03 ± 0.50 g; mean ± standard deviation) were submitted to concentrations of 40, 50, 60, 70 and 80 µl L-1 of clove, 150, 200, 250, 300 and 350 µl L-1 of basil and 200, 300, 400, 500 and 600 µl L-1 of tea tree oils (n=10/concentration), previously defined in pilot tests. Individually and only once, fish from each treatment were placed in a glass recipient containing 1 L of seawater at a temperature of 25 °C, salinity of 35 g L-1 and the specific concentration of diluted EO (stock solution). Control (only seawater) and blank (seawater and ethanol at the highest concentration used to dilute the oils) treatments were also conducted. After reaching the stage of surgical anaesthesia, fish were submitted to biometry and a sensibility test. After that, they were transferred to clean seawater for anaesthesia recovery. The times of induction needed to reach each anaesthesia stage and anaesthesia recovery were recorded. Animals were observed for 72 hours after the procedures. All the EO provoked anaesthesia and analgesic effects in A. clarkii, but basil oil is not recommended because it caused involuntary muscle contractions and mortality in 100% and 12% of fish, respectively. The lower concentrations that promote suitable induction and recovery times are 50 µl L-1 of clove oil and 500 µl L-1 of tea tree oil. However, due to its complementary high analgesic efficiency, clove oil is recommended as the ideal anaesthetic for A. clarkii.

A review of spawning induction, larviculture, and juvenile rearing of the fat snook, Centropomus parallelus.

The fat snook, Centropomus parallelus, is a commercially valuable marine fish species with potential for aquaculture. This paper describes the development of technology for mass production of fat snook juveniles at the Experimental Fish Hatchery of the Universidade Federal de Santa Catarina, focusing on research about reproduction, larviculture, and juvenile rearing. Induced spawning of wild fat snook was first achieved in 1991 with a single injection of human chorionic gonadotropin (hCG). There was a substantial increase in egg quality when broodstock was conditioned in maturation rooms and induced to spawn. Different dosages of luteinizing hormone-releasing hormone analogue (LHRHa) with saline injection and colesterol implant were also tested. As fat snook exhibits group-synchronous oocyte development, females could be induced to spawn (with 35-50 mug kg(-1) of LHRHa) once a month, resulting in up to four consecutive spawnings. Results of larval culture were highly variable at the beginning; survival rates were frequently around 1% until the juvenile stage. Several experiments were conducted to evaluate the effect of environmental factors and feeding quality on survival and growth. With the improvement of the spawning induction technique and better larviculture practices, survival rates increased to 10-30%. Studies on the particular requirements of juveniles in terms of stocking density, feeding, nutrition, and environmental factors were also performed in order to improve growth rates and feed utilization. The present study demonstrates the feasibility of mass production of fat snook juveniles. However, further research is needed to develop cost-effective grow-out technology.

The significance of cortisol on acclimation to salinity in pejerrey Odontesthes bonariensis

The role of cortisol on the osmoregulation of pejerrey Odontesthes bonariensis at different salinities was investigated in adult fish injected with 0.7mg hydrocortisone per 100g body weight of fish, and transferred to 0, 5 and 20ppt of NaCl. Blood cortisol was 566ng/ml at the beginning of the experiment (0h) but surged to 1250ng/ml within 3h in cortisol-injected fish. Cortisol levels were influenced not only by treatment but also by time, being higher at 3h compared to 24h. Salinity level, time of exposure and their interaction, but not cortisol treatment, significantly affected plasma osmolality and the concentration of ions Cl- and Na+. This study showed that exogenous cortisol does not seem to play a significant role on the regulation of plasma osmolality and concentration of individual ions in pejerrey

Investigou-se a participação do cortisol na osmoregulação de peixe-rei Odontesthes bonariensis, em diferentes salinidades, em peixes adultos injetados com 0,7mg hidrocortisona por 100g de peso corporal, e transferidos para 0, 5 e 20ppt de NaCl. No inicio do experimento (0h), o cortisol encontrado no plasma foi de 566ng/ml, aumentando para 1250ng/ml em 3h em peixes injetados com cortisol. A concentração de cortisol foi influenciada não somente pelo tratamento, mas também pelo tempo, sendo maior 3h após a inoculação, comparada à 24h. A salinidade, o tempo de exposição e a interação desses dois fatores, mas não o tratamento com o cortisol, afetaram significativamente a osmolaridade e a concentração dos íons Cl- e Na+ do plasma. Este estudo mostrou que, o cortisol exógeno não influi significativamente na regulação da osmolaridade e da concentração de íons Na+ e Cl- no plasma em peixe-rei