Efecto de la adición de aceite esencial de Myrcia sylvatica (G. Mey.) DC (AEMS) en la dieta de dorada (Sparus aurata) bajo situaciones de estrés crónico producido por densidad

Trabajo presentado en el XV Congreso Nacional de Acuicultura y el I Congreso Ibérico de Acuicultura, celebrados en Huelva del 13 al 16 de octubre de 2015.[ES] Unas condiciones de cultivo inadecuadas (por ejemplo la alta densidad), causan estrés a los peces, afectando el metabolismo de lípidos, hidratos de carbono y proteínas. El objetivo de este estudio fue evaluar los efectos de la adición de aceite esencial de Myrcia sylvatica (AEMS) en la dieta de ejemplares de Sparus aurata en situaciones de baja y alta densidad. Los juveniles de dorada fueron distribuidos y alimentados con tres dietas experimentales durante tres meses: i) control, ii) 1,0 mL AEMS/kg de pienso, y iii) 2.0 mL AEMS/kg de pienso. Transcurrido este tiempo, cada grupo experimental fue dividido en dos nuevas condiciones: baja y alta densidad de carga (BD, 5 kg/m3 y AD, 40 kg/m3, respectivamente) para tener un total de seis grupos experimentales: i) control-BD, ii) control-AD, iii) 1,0 mL-BD, iv) 1,0 mL-AD, v) 2,0 mL-BD, y vi) 2,0 mL-AD). Después de 22 días bajo estas condiciones, 10 individuos de cada tratamiento fueron anestesiados y se extrajeron muestras de sangre e hígado para el análisis de cortisol y metabolitos. Nuestros resultados muestran que la adición de AEMS disminuye los niveles de cortisol en condiciones de BD y AD. Además, se observa que dietas suplementadas con dosis cercanas a 2,0 mL AEMS/kg de pienso originan una reorganización metabólica para poder afrontar la situación de estrés producido por la alta densidad de carga.[EN] Inadequate stocking densities (e.g. high stocking density) activated stress system, affecting the metabolism of lipids, carbohydrates and proteins. The aim of this study was to evaluate the effects of adding essential oil of Myrcia sylvatica (EOMS) in the diet of Sparus aurata juveniles held at different stocking densities. Juvenile specimens were distributed into the three experimental groups, feeding three different diets during three additional months: i) control, ii) 1.0 mL EOMS/kg of feed, and iii) 2.0 mL EOMS/kg feed. After that, each experimental group was divided in two different conditions: low and high stocking densities (LD-5 kg/m3 and HD-40 kg/m3, respectively) constituting a total of six different treatments: i) control-LD, ii) control-HD, iii) 1.0 mL-LD, iv) 1.0 mL-HD, v) 2.0 mL-LD, and vi) 2.0 mL-HD). After 22 days under these conditions, 10 individuals from each treatment were anesthetized and sampled for plasma and liver. These samples were analysed for cortisol and metabolites analysis. Our results shown that EOMS decreased plasma cortisol levels under LD and HD conditions. Moreover, it is observed that diets supplemented with 2.0 mL EOMS/kg of food originates a metabolic reorganization to cope with the stressful situation produced by higher stocking densities.Etiane M. H. Saccol y Y.A. Parrado-Sanabria contaron con el apoyo de becas de doctorado y máster de la Comisión de Formación de Personal de Nivel Superior (CAPES) y a la Asociación Universitaria Iberoamericana de Postgrado (AUIP), respectivamente. Este trabajo ha sido financiado por el proyecto AGL2013-48835-C2-1-R (MINECO, España) concedido a J.M. Mancera.N

Evaluación de la adición de aceite esencial de Myrcia sylvatica (G. Mey.) DC (AEMS) en la dieta y su efecto sobre el crecimiento y fisiología de la dorada (Sparus aurata)

Trabajo presentado en el XV Congreso Nacional y el I Congreso Ibérico de Acuicultura (Acuicultura, cultivando el futuro), celebrado en Huelva del 13 al 16 de octubre de 2015.[ES] Las actividades acuícolas producen situaciones de estrés que disminuyen el bienestar de los peces cultivados. El objetivo de este estudio fue evaluar los efectos de la adición del aceite esencial de Myrcia sylvatica (AEMS), una sustancia que mitiga la activación del sistema de estrés en otras especies de teleósteos, en la dieta de la dorada (Sparus aurata). Los juveniles de dorada fueron proporcionados por los Servicios Centrales de Investigación de Cultivos Marinos (SCI-CM, Universidad de Cádiz), aclimatados durante un mes en tanques de 1000 L y distribuidos en 9 tanques de 80 L (densidad de carga inicial: 2,76 ± 0,013 g/L) que constituyeron los tres grupos experimentales por triplicado: i) control, ii) 1,0 mL AEMS/kg de pienso, y iii) 2,0 mL AEMS/kg de pienso. Tras 90 días, los peces (n = 9 por grupo experimental) fueron anestesiados, medidos y pesados. Posteriormente, se extrajeron muestras de sangre e hígado para el análisis de cortisol y metabolitos. La adición en la dieta de AEMS disminuyó los niveles de cortisol y triglicéridos en plasma, así como del glucógeno hepático. Por tanto, nuestros resultados sugieren que la adición de AEMS en la dieta (dosis entre 1,0-2,0 mL AEMS/kg de pienso) podría mejorar el bienestar animal de esta especie durante su cultivo.[EN] Aquaculture activities promote stress situations that decrease fish welfare. In this sense, the objective of this study was to evaluate the effects of adding essential oil of Myrcia sylvatica (EOMS), a substance that has been used to mitigate activation of stress system in other teleost, in the diet of gilthead sea bream (Sparus aurata). Juveniles specimens were provided by the Servicios Centrales de Investigación de Cultivos Marinos (SCI-CM, University of Cadiz), acclimated for one month in 1000 L-tanks and distributed in 9 tanks of 80 L (initial stocking density: 2.76 ± 0.013 g/L), which constituted the three experimental groups in triplicate: i) control, ii) 1.0 mL EOMS/kg food, and iii) 2.0 mL EOMS/kg food). After 90 days, fish (n = 9 fish per group) were anesthetized measured and weighed. Subsequently, blood and liver samples were extracted for cortisol and metabolites analysis. The addition of EOMS in diet decreased plasma cortisol levels and plasma triglycerides, as well as liver glycogen. Therefore, our results suggest that the addition of EOMS in the diet (doses between 1.0-2.0 mL EOMS/kg food) could promote fish welfare of this specie in culture.Este trabajo ha sido financiado por el proyecto AGL2013-48835-C2-1-R (MINECO, España) concedido a J.M.M.N

Physiological changes in silver catfish (Rhamdia quelen) transported with essential oil of Myrcia sylvatica

Trabajo presentado en el 10º Congreso de la Asociación Ibérica de Endocrinología Comparada, celebrado en Castellón del 23 al 25 de septiembre de 2015.Aquaculture practices include several procedures as capture, handling and transport, which cause stress in fish. Anesthetics or sedative substances have been used to reduce this stress. The aim of this study was to evaluate the effects of essential oil of Myrcia sylvatica (EOMS) in the water on stress system activation in the silver catfish Rhamdia quelen summited to transport. Fish were captured in the production ponds and transferred to a 250-L tanks (density of 54 kg/m3). After 24 hours, 10 fish were caught, euthanized by section of the spinal cord and sampled (basal group). The remaining fish were placed in plastic bags containing 5 L of water (density of 150 kg/m3) with different doses of EOMS (0, 25 or 35 μL/L diluted in 315 μL/L ethanol), in triplicate, and transported for 6 h. After transportation, 10 animals of each group were captured, euthanized and sampled. Cortisol and glucose levels in plasma, as well as hypothalamic corticotrophin-releasing hormone (CRH) and pituitary proopiomelanocortin (POMC) “a” and “b” mRNA expressions were determined. Cortisol levels and CRH expression enhanced after 24h of handling, decreasing during the transport with addition of EOMS. Expression of POMCa was higher in fish transported with 25 μL/L respect to the rest of groups. Therefore, it is suggested the use of EOMS for transporting fish in order to avoid the stress associated with this procedure.Financial Support: FAPERGS/PRONEX, CAPES, CNPq.Peer reviewe

Myrcia sylvatica essential oil in the diet of gilthead sea bream (Sparus aurata L.) attenuates the stress response induced by high stocking density

The effects of diet supplemented with Myrcia sylvatica essential oil (EOMS) on growth and stress tolerance to different stocking densities were assessed in Sparus aurata. Initially, three experimental groups were established: (i) control, (ii) 1.0 and (iii) 2.0 ml EOMS/kg dry feed. After 90 days, nine fish per group were anaesthetized, weighed and sampled for metabolic analysis. The remaining fish were divided into two different conditions: low (LD—5 kg/m3) and high (HD—40 kg/m3) stocking densities, constituting a final experimental setup with six treatments. After 22 days, 10 individuals per treatment were anaesthetized and sampled for biochemical analysis. EOMS feeding for 90 days did not interfere with growth, although it was effective in reducing cortisol levels and the activation of lipid and carbohydrate metabolism. The HD interfered in growth performance, increased the lactate levels in the control group, reducing also hepatic glycogen levels without dependence on diet supplementation. The 2.0 ml EOMS + LD group increased the growth parameters and decreased the cortisol and triglycerides levels. Additionally, metabolism adjustment was observed to provide energy during LD and HD conditions, indicating that diets supplemented with EOMS produce metabolic reorganization to maintain body homeostasis, suggesting its use as a beneficial supplement in fish.Spanish Ministry of Science and Education, Grant/Award Number: AGL2013-48835-C2-R and AGL2016-76069-C2-1-R; Spanish Ministry of Education, Economy and Competitiveness (MINECO); CAPES (Ministry of Education of Brazil, Brazil); PDSE-CAPES (Programa Institucional de Bolsas de Doutorado Sanduíche no Exterior, Grant/Award Number: 5055/14-8); CNPq research fellowshipPeer reviewe

Myrcia sylvatica essential oil mitigates molecular, biochemical and physiological alterations in Rhamdia quelen under different stress events associated to transport

The effects of pre-transport handling and addition of essential oil of Myrcia sylvatica (EOMS) during transport on stress pathways activation in Rhamdia quelen were investigated. Fish (n = 400, 25.2 ± 2.9 g) were captured in production ponds and transferred to 100-L tank (density 100 g L− 1). After 24 h, 10 fish were sampled (before transport group). The remaining fish were placed in plastic bags (n = 30 or 32 fish per bag, density 150 g L− 1) containing 5 L of water (control), ethanol (315 μL L− 1, vehicle) or EOMS (25 or 35 μL L− 1), in triplicate, transported for 6 h and sampled (n = 10 animals per group). Indicators of stress and metabolism, as well as mRNA expression of brain hormones were evaluated. Previously, full-length cDNAs, encoding specific corticotropin-releasing hormone (crh) and proopiomelanocortins (pomca and pomcb), were cloned from whole brain of R. quelen. Crh expression increased after 24 h of capture and handling, whereas cortisol and glucose plasmatics enhanced their values in the control group. Transport with EOMS reduced plasma cortisol and lactate levels, while ethanol and EOMS groups increased Na+/K+-ATPase gill activity compared to control. Gene expression of crh, pomcb, prolactin and somatolactin mRNAs were lower after transport with EOMS compared to control. EOMS was able to mitigate the stress pathways activation caused by transport, maintaining a balance in body homeostasis. Thus, EOMS is recommended as sedative in procedures as transport and the pre-transport handling requires greater attention and use of tranquilizersWe would also like to thank the financial support received by CAPES (Ministry of Education of Brazil, Brazil) through the program PDSE-CAPES (Programa Institucional de Bolsas de Doutorado Sanduíche no Exterior - Process: 5055/14-8) awarded to E.M.H.S.; the CNPq research fellowship awarded to B.B., project ADAPTA II (process number 465540/2014-7 CNPq) and the project AGL2013-48835-C2-R (Ministry of Science and Education, Spain) awarded to J.M.M. J.A.M-S is currently funded by a Postdoctoral Research Fellowship (Juan de la Cierva-Formación, Reference FJCI-2014-20161) from the Spanish Ministry of Education, Economy and Competitiveness (MINECO).Peer reviewe