Effects of diets, with different levels of n-3 HUFA, designed specifically for gilthead seabream (Sparus auratus L.) broodstock on spawning quality

The effects of dietary lipid levels in the spawning quality has been studied in several cultured fish species. Works like those of Watanabe et al. (1984 a); Mourente et al. (1989); Dhert et al. (1991); Bruce et al. (1993); Navas et al. (1997); Rodriguez et al. (1998); Lavens et al. (1999); Furuita et al. (2002, 2003 b); Mazorra et al. (2003); Fernandez- Palacios (2005) and Aijun et al. (2005) show that lipids and fatty acids are the dietetic components that have more influence in the spawning quality, specially in those species with continuous spawning which display short vitellogenesis periods and are able to incorporate these dietetic components in eggs during the spawning period. Diets for gilthead sea bream (Sparus aurata) broodstock with dietary levels of 2.84% n-3 HUFA, combined with levels of 250 mg/kg vitamine E rasure good spawning quality. Putting so indicative the importance for an effective utilization of essential fatty acids the use of adequate levels of antioxidants.

Harina de erizo de mar (Diadema antillarum) com ingrediente alternativo en piensos para bocinegro (Pagrus pagrus): efecto sobre el crecimiento y utilización de la dieta

[EN]The effect of dietary inclusion of sea urchin meal (Diadema antillarum) on growth and feed utilization was investigated in a growth trial with red porgy (Pagus pagrus) of 208g initial body weight, during 6 month feeding period. High quality fish meal and fish oil diet was used as a control (Diet C); urchin meal was included at 8% and 16% dietary levels (EM8 and EM16). Compared to the control diet higher values for absolute and relative final weight and SGR were obtained either for fish fed EM8 and EM16 diets; for the latter diets values for FCR and final HSI were significantly smaller respect to those for the control diets. No differences were found among diets for the total feed intake, VSI and K factor. Obtained results indicate the suitability of the sea urchin meal as alternative ingredient in diets for the red porgy, improving fish growth and feed utilization. More studies are being done at the moment in red porgy and other fish species in order to better determine the optimum dietary levels taking into account other important culture and quality parameters.

Efecto de la inclusión de harinas de cangrejo de diferente origen en piensos para bocinegro (Pagrus pagrus) sobre la textura, oxidación y composición del filete

[EN]The inclusion of two different crab meals in diets on fillet quality parameters was investigated in a six month growth trial with red porgy (Pagus pagrus). A high quality fish meal and fish oil diet was used as a control (Diet C). Fish meal protein in the control diet was replaced by increasing levels of protein from a river crab meal (Procamburus clarkii) (CR) and a marine crab meal (Chaceon affinis) (CM) at 10% and 20% each of them. The inclusion of both crab meals in diets, either at 10% and 20% substitution levels, did not affect the texture quality parameters of flesh except for the adhesiveness, where animal fed on CR20 showed the smallest value respect to those fed the Diet C. Compared to the control fish, a reduction of the fillet lipid oxidation indicated by the Tbars index was observed for fish fed both crab meal based diets, at the higher inclusion level (20%). Increasing dietary levels of the marine crab meal showed an increment of the monoenoicos, n-9 and oleic fatty acid content in the fillets. Results indicate that both crab meals used in present study are suitable as alternative ingredients for red porgy diets in terms of fish flesh quality.

Captura, aclimatación y maduración en cuatividad de reproductores salvajes de Pseudocaranx dentex en Canarias

[EN]The present work describes the procedures for capture, maintenance and evolution of a Pseudocaranx dentex stock in the Instituto Canario de Ciencias Marinas. Forty fish captured in a commercial off-shore fish farm, were transferred to on land facilities, acclimatation to tanks and inert food was successfully carried out, with 100% survival after 1 year. Initial fish weight (4,15kg) was , followed and sampled to determine individual growth in weight and size. Also, the evolution of its sexual maturity state was evaluated at capture and one year after to determine the maturation of fish for future juvenile production. Fish mature in captivity, but natural spawn was unsuccessful

Engorde de pulpo común Octopus vulgaris en jaulas en la comunidad Canaria [Material gráfico] [Recurso electrónico] : efecto de la dieta y la densidad inicial

Octopus vulgaris on-growing in floating cages is a promising activity implemented in Spain at industrial level, with productions of 16-32 tons/year from 1998. Nevertheless, some aspects of the culture system need to be evaluated to warrantee its profitability. In the present work absolute growth rate (AGR, g/day) and mortality (%) under two initial rearing densities, 10 and 17 kg/m3, were compared under two feeding regimes over 15 weeks. One diet was composed by bogue, supplied as ?discarded? species from local fish farms. The other diet was based on a 40-60% discarded bogue-crab Portunus pelagicus. Half of the reared octopuses were PIT-tagged and two sampling points were established along the experimental period. Regardless of dietary treatment, up to the 11th week, growth was 19 and 13 g./day for the low and high rearing density. On the other hand, up to the 11th week mortality was higher in the control diet fed group (30%), reaching 74-84% by the end of the experiment regardless of rearing density and dietary treatment, which could suggest some nutritional imbalance of the tested diets.

Pre-engorde de pulpo común Octopus vulgaris con 3 dietas basadas en descartes de acuicultura en la comunidad Canaria

On-growing of Octopus vulgaris fed different feeds has shown promising results. Nevertheless, since the minimum legal size for octopus fisheries in spain i sin most of experimental ongrowing of this species an average weight over 750-1000kg was utilized with g (and little research has been conducted in order to evaluate the effect of these diets on smaller individuals. The present work evaluates the effect of 3 diets based on bogue, obtained as ?discarded? species from local fish farms, on ingestion and growth of O. vulgaris weighing 400 g. The 1st diet was composed by discarded bogue, the 2nd diet by a 40-60% discarded bogue-crab Portunus pelagicus and the 3rd diet was presented as a moist diet based on discarded bogue. A triplicate of four octopuses per treatments, male:female 1:1, were kept in circular 400 l tanks and fed each diet for 4 weeks. Absolute growth rate (AGR, g./day), standard feeding rate (SFR, %/day) and feed efficiency (FE) were calculated. The addition of crab to the diet increased SFR which underlines different feeding habits when compared with 0.8-1 kg octopuses. Lower growth and higher FE was recorded with the moist diet, probably due to high disintegration of this kind of feed.

Eficacia de la inducción hormonal con distintas dosis de GnRHa en corvina (Argyrosomus regius)

[EN]The objective of this experiment was to determine the efficacy of different GnRHa doses for the induction of the spawning in meagre broodstock born in captivity. Five experimental groups were established, and one control group that was not injected. Fish were acclimated in six 10 m3 tanks, and in each tank there was 3? and 4? with an average weight of 8.33±0.97 and 8.47±1.09 kg respectively. Throughout the experimental period (April 14- June 2 of 2009), broodstock were induced on a weekly basis. Each time one female and two males from each of the five experimental groups were induced with an injection of GnRHa at the doses of 10, 20, 30, 40 and 50 ?g.kg-1 respectively. No significant differences were found in any of the controlled parameters: % of injected females with spawning, latency period and % of spawns. Although the highest spawning ratio was obtained with the lower doses, a statistically significant negative correlation between the doses and percentage spawning was found.

Evaluación de 2 sistemas de cultivo en pulpos macho Octopus vulgaris: efecto de la talla inicial y de la dieta

[EN]Octopus vulgaris on-growing in floating cages has shown promising results. Nevertheless, some aspects of the culture system need to be evaluated to warrantee its profitability. In the present work individual and group rearing, in PVC net compartments and floating cages respectively, are compared under two dietary treatments. One diet is composed by bogue, supplied as ?discarded? species from local fish farms, and the other is based on a 40-60% discarded bogue-crab Portunus pelagicus. Besides, the effect of initial size is also evaluated. All octopuses were PIT-tagged and the experiment lasted 2 months. Absolute growth rate (AGR, g./day) and mortality (%) were calculated. Control diet generated higher growth rates and lower mortality which suggests different crab requirements at higher rearing temperatures. High mortality recorded in individual rearing could be related with high initial rearing density and temperatures.

Nuevas aportaciones al estudio de la organogénesis en larvas de corvina (Argyrosomus Regius Asso, 1801)

La corvina (Argyrosomus regius) es un teleósteo de la familia Scianidae, que en los últimos años ha despertado un gran interés en acuicultura por su rápido crecimiento y la calidad de su carne. A su vez, se trata de una de las especies denominadas ?nuevas? que no pertenecen a la familia de los espáridos, y permite diversificar la oferta de la piscicultura marina. Las primeras aportaciones al estudio histológico del desarrollo larvario de esta especie fueron realizados por Jiménez et al. (2007). El presente trabajo incrementa la información existente, durante los dos primeros meses de vida de esta especie, lo que permitirá optimizar el cultivo larvario. Para ello se analiza la relación entre el desarrollo de sistema digestivo, la vejiga natatoria y el sistema visual. Los resultado demuestran que la corvina es una especie de rápido desarrollo y muy susceptible a las condiciones de cultivo durante su fase larvaria, condicionando éstas su crecimiento. A su vez el presente estudio ratifica que las características morfológicas y la organogénesis están directamente relacionadas con la longitud de la larva, independientemente de la edad de la misma.

Protocolo de anestesia y recuperación para estudio de morfometría de juveniles de caballito de mar, (Hippocampus hippocampus (Linnaeus, 1758)

Anaesthetic and Recovery Protocol for morfometric study of Atlantic seahorse, Hippocampus hippocampus (Linnaeus, 1758), juveniles. Some morphometric studies in marine organism need anaesthetics in order to avoid animal?s sacrifice and allow its recovery. In this study different natural clove essential concentrations has been tested in Atlantic seahorses, Hippocampus hippocampus (Linnaeus, 1758) aged 13 (trunk length 7,48 ± 1,14 mm) and 22 days (trunk length 9,09 ± 1,62 mm). An inversed relation was observed between anaesthetic concentration and effective time. The concentration allowing measures was 25 ppm. This procedure allowed 100% survival rate.

Efecto de la primera alimentación en la supervivencia y el crecimiento de crías de caballito de mar, Hippocampus hippocampus (Linnaeus, 1758)

[EN]Effects of first feeding on survival and growth of Atlantic seahorse juveniles, Hippocampus hippocampus, (Linnaeus, 1758). In this study, two experimental protocols were tested: a first treatment (RA), in which larvae were fed exclusively on rotifers until day 5, and then on Artemia, and a second treatment (A) where larvae were only fed on Artemia. We attempted to improve survival and growth by comparing different diets in the first days of life. The results showed excellent survival (60% average) and growth in juveniles exclusively fed with Artemia, with better values than those obtained by other authors for this species. In comparison, high mortality and poor growth were observed on the first days in larvae fed rotifers.