Weaning of Senegalese sole (Solea senegalensis) postlarvae to an inert diet with a co-feeding regime | Destete de postlarvas del lenguado senegalés (Solea senegalensis) a una dieta inerte utilizando un régimen de coalimentación

The objective of this study was to evaluate the weaning success of Senegalese sole, Solea senegalensis, postlarvae when cofed a compound diet, by means of the analysis of growth parameters (relative growth rate [RGR] and condition factor [K]), survival, protein and lipid content. Total ammonia in the rearing water was also measured. The experiment lasted for 46 days (36 to 82 days posthatching). One group was fed only with enriched Artemia sp. metanauplii (Artemia treatment), whereas in another group, the Artemia sp. metanauplii were gradually replaced by the International Council for the Exploration of the Sea (ICES) diet over a period of 39 days (ICES treatment). Postlarvae were sampled on rearing days 0, 9, 23, 30, 39 and 46 for growth and biochemical analysis. Water was sampled on rearing day 30 during a 24-h cycle in both treatments. Postlarvae from the ICES treatment were weaned, though by the end of the experiment the Artemia treatment exhibited significantly higher values for growth, RGR, K and survival rates (P <0.05). No significant differences were observed concerning total lipid content. Protein content was significantly higher for the Artemia treatment after 46 days of rearing (P < 0.05). The total ammonia nitrogen concentration in the water increased after each meal and remained below a harmless level for postlarvae.El objetivo de este estudio consistió en evaluar el éxito del destete de postlarvas del lenguado senegalés, Solea senegalensis, utilizando un régimen de coalimentación. El estudio se realizó mediante el análisis de parámetros de crecimiento (tasa de crecimiento relativa [RGR] y factor de condición [K]), supervivencia y contenido de proteínas y lípidos. La concentración del amonio total en el agua de cultivo también fue analizada. El experimento se realizó durante 46 días (de 36 a 82 días posteclosión). Un grupo de postlarvas se alimentó únicamente con metanauplios de Artemia sp. enriquecidos (tratamiento con Artemia), mientras que en otro grupo los metanauplius de Artemia sp. fueron gradualmente substituidos por la dieta del International Council for the Exploration of the Sea (tratamiento ICES) durante un periodo de 39 días. Las postlarvas se muestrearon durante los días 0, 9, 23, 30, 39 y 46 de cultivo para el estudio de crecimiento y el análisis bioquímico Las muestras de agua se tomaron el día 30 de cultivo durante un ciclo de 24 h en ambos tratamientos. Las postlarvas del tratamiento ICES fueron destetadas, aunque al final del experimento se registraron valores significativamente mayores en relación al crecimiento, RGR, K y tasas de supervivencia (P < 0.05) en el tratamiento con Artemia. No se observaron diferencias significativas en el contenido total de lípidos. El contenido de proteínas fue significativamente mayor en el tratamiento con Artemia a los 46 días de cultivo (P < 0.05). La concentracion de amonio total en el agua se incrementó después de cada toma de alimento pero se mantuvo por debajo del nivel tóxico para las postlarvas de peces marinos

Weaning of Senegalese sole (Solea senegalensis) postlarvae to an inert diet with a co-feeding regime

The objective of this study was to evaluate the weaning success of Senegalese sole, Solea senegalensis, postlarvae when co-fed a compound diet, by means of the analysis of growth parameters (relative growth rate [RGR] and condition factor [K]), survival, protein and lipid content. Total ammonia in the rearing water was also measured. The experiment lasted for 46 days (36 to 82 days posthatching). One group was fed only with enriched Artemia sp. metanauplii (Artemia treatment), whereas in another group, the Artemia sp. metanauplii were gradually replaced by the International Council for the Exploration of the Sea (ICES) diet over a period of 39 days (ICES treatment). Postlarvae were sampled on rearing days 0, 9, 23, 30, 39 and 46 for growth and biochemical analysis. Water was sampled on rearing day 30 during a 24-h cycle in both treatments. Postlarvae from the ICES treatment were weaned, though by the end of the experiment the Artemia treatment exhibited significantly higher values for growth, RGR, K and survival rates (P < 0.05). No significant differences were observed concerning total lipid content. Protein content was significantly higher for the Artemia treatment after 46 days of rearing (P < 0.05). The total ammonia nitrogen concentration in the water increased after each meal and remained below a harmless level for postlarvae.info:eu-repo/semantics/publishedVersio

High-glucose feeding of gilthead seabream (Sparus aurata) larvae: effects on molecular and metabolic pathways

Nutritional programming has begun to arouse interest as a novel tool to alter specific metabolic pathways or functions in farmed animals. The aim of the present study was to explore the potential of early glucose stimuli to induce changes in nutrient metabolism of gilthead seabream. Nutritional conditioning was performed by delivering glucose-rich feed at three distinct recurrent periods of larval feeding regime: during first-feeding with rotifers (3 days after hatching, DAH) and mid-feeding with Artemia metanauplii (20DAH) and the beginning of inert diet feeding (30DAH), called the Recurrent treatment (REC). As opposed, the control treatment (CTRL) did not experience any glucose stimuli. At post-larval stage (from 50 to 60DAH), both treatments were challenged with a high-carbohydrate diet (50%). The immediate response to the early stimuli was assessed through gene expression of metabolic markers and by nutrient metabolism using [C-14] tracers. Each dietary stimulus induced metabolic changes on REC larvae, shown by altered expression of some genes, including those involved in glycolysis, and by a different pattern of glucose utilization. However, none of the molecular adaptations (except G6PDH gene) were persistent in the viscera and muscle of challenged post-larvae from REC group. In contrast, the glucose metabolism of challenged REC post-larvae revealed a shift towards a higher catabolism and lower glucose retention in tissues, compared to the CTRL group, suggesting an improvement of glucose oxidation pathways. In addition, the REC group showed a higher bio-conversion of glucose into lipids, indicating enhanced hepatic lipogenesis. The early stimuli did not affect the relative retention or use of amino acids or the growth and survival of challenged fish, up to 60DAH. In summary, although not substantiated at a molecular level, our data reveal that a recurrent high-glucose stimulus during larval stages affects the short-term modulation of pathways for glucose utilization in gilthead seabream. (C) 2015 Elsevier B.V. All rights reserved

Improving growth performance of Senegalese sole postlarvae

Tese dout., Aquacultura, Universidade do Algarve, 200

Type of hormonal treatment administered to induce vitellogenesis in European eel influences biochemical composition of eggs and yolk-sac larvae

Egg biochemical composition is among the main factors affecting offspring quality and survival during the yolk-sac stage, when larvae depend exclusively on yolk nutrients. These nutrients are primarily embedded in the developing oocytes during vitellogenesis. In aquaculture, assisted reproduction procedures may be applied enabling gamete production. For the European eel (Anguilla anguilla), reproductive treatment involves administration of pituitary extracts from carp (CPE) or salmon (SPE) to induce and sustain vitellogenesis. In the present study, we compared the influence of CPE and SPE treatments on offspring quality and composition as well as nutrient utilization during the yolk-sac stage. Thus, dry weight, proximal composition (total lipid, total protein), free amino acids, and fatty acids were assessed in eggs and larvae throughout the yolk-sac stage, where body and oil-droplet area were measured to estimate growth rate, oil-droplet utilization, and oil-droplet utilization efficiency. The results showed that CPE females spawned eggs with higher lipid and free amino acid contents. However, SPE females produced more buoyant eggs with higher fertilization rate as well as larger larvae with more energy reserves (estimated as oil-droplet area). Overall, general patterns of nutrient utilization were detected, such as the amount of total lipid and monounsaturated fatty acids decreasing from the egg stage and throughout the yolk-sac larval stage. On the contrary, essential fatty acids and free amino acids were retained. Notably, towards the end of the yolk-sac stage, the proximal composition and biometry of surviving larvae, from both treatments, were similar

Daily oxygen consumption rhythms of Senegalese sole solea senegalensis (Kaup, 1858) juveniles

Senegalese sole is known to be a species with pronounced nocturnal feeding behaviour. However, as for most fish species, there is a lack of knowledge concerning the influence of such biological rhythmon metabolic rate. The aim of this study was to determine whether individual variation in routine and fed metabolic rate was affected by daily light–dark rhythms in juveniles of Senegalese sole. The individual oxygen consumption measurements in Senegalese sole juveniles were determined by flow-through respirometry, at fasted conditions and after the fish were fed a single meal, the meal time started at 0930 h and fish fed ad libitum for 30 min. The measurements were made during 22 h, of which 8 h was in the light and 14 h in the dark, and started immediately after transfer to the respiratory chambers at 1100 h. The results suggest an influence of light–dark cycles in routine metabolism. It was observed that oxygen consumption increased during the dark phase in fasted fish (FAST) but was higher during the light phase in fed fish (FEED). However, when feed is provided during the light phase, juveniles are capable of shifting oxygen consumption rhythms to respond to the energetic demands of digestion and growth. These results suggest that routine metabolism varies according to the species natural habits as Senegalese sole is known to be nocturnal. The findings of this study underline the importance of understanding the biological rhythms of the species under study before metabolic data are interpreted

Pigmentation abnormalities in juveniles sole Solea senegalensis Kaup, 1858

The Senegalese sole, Solea senegalensis Kaup, 1858, has a high market value, and is therefore considered a potentially valuable new species for aquaculture. To attain its potential, it is necessary to improve the production of juveniles, so that production of market-size fish can get fully underway. The mass production of sole in aquaculture will only be possible when hatcheries begin to be able to produce juveniles for ongrowing. Several studies have been conducted to improve sole production (Dinis, 1986, 1992; Dinis et al., 1999), and some pigmentation abnormalities were reported, which require further study. The present paper describes the principal abnormalities found in sole pigmentation. Studies indicate that 11 % of juveniles present pigmentation problems, which could be considered a problem insofar as mass production is involved, because such fish would be difficult to market.El lenguado Solea senegalensis Kaup, 1858 es una especie de valor comercial elevado y está considerada de interés potencial para la acuicultura. En consecuencia, existe una creciente necesidad de desarrollar el cultivo larval de esta especie a escala industrial y producir juveniles para engorde en las piscifactorías. Se han realizado diversos trabajos con el objetivo de mejorar la metodología en la producción de S. senegalensis (Dinis, 1986, 1992; Dinis et al., 1999) y se señalan algunas limitaciones: entre ellas, las anomalías de pigmentación. Se describen aquí las principales anomalías en la pigmentación del lenguado a partir de puestas naturales de reproductores salvajes mantenidos en cautividad. El porcentaje total de alevines mal pigmentados fue del 11 %, lo que puede constituir un problema cuando se pretende la producción a gran escala, pues entraña un obstáculo para su comercialización, con el consiguiente descenso de la rentabilidad.Instituto Español de Oceanografí

Nutrition, quality and performance in marine fish larvae

O cultivo de larvas de peixes marinhos é caracterizado por altas mortalidades e por problemas de qualidade, nomeadamente malformações esqueléticas. A solução de parte destes problemas passa por uma melhor compreensão dos requisitos nutricionais. Este trabalho pretende fazer uma revisão de trabalhos recentes que demonstram como os aminoácidos, os ácidos gordos e a vitamina K, mas também o regime alimentar, podem influenciar a qualidade e a performance das larvas de peixes marinhos

Hormonal induction of Atlantic dusky grouper (Epinephelus marginatus) broodstock

Immature fish and young females were sex reversed using hormonal induction in two consecutive years. In the first year one permanent male was obtained. Collected sperm of both years ranges from 30 μl to 300 μl and cell concentration varies from 3 to 6.5 x109 spermatozoa/ml. Atlantic dusky grouper can successfully be induced to functional males with 17α-methyltestosterone implants

Effect of variable levels of dietary cholesterol and plant sterols on the growth performance and bone metabolism in gilthead seabream (Sparus aurata) juveniles

Cholesterol is found in all animal tissues and is an important component of biological cell membranes with functions such as precursor to bile acids, hormones and vitamins. Fish meal and fish oil are cholesterol-rich ingredients. Replacement of these marine-derived ingredients by plant proteins and vegetable oils tends to reduce dietary cholesterol levels