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.

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.

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.

Efecto de la densidad larvaria y secuencial alimentaria en el cultivo larvario de corvina (Argyrosomus regius Asso, 1801) durante el primer mes de vida

Effect of larval density and feeding sequence on meagre (Argyrosomus regius Asso, 1801) larval rearing during the first month of life. In the present work two comparative studies of the effect of larval density and feeding sequence were performed. For such, two initial larval densities, 50 larvae.l-1 and 100 larvae.l-1 were established. In each density three feeding sequences were tested, applying different combinations of rotifers (Brachionus sp.) and Artemia sp. at different larval ages. After 30dah, standard length, dry weight and final survival were determined. Final survival was affected by initial larval density and feeding sequence. Lower density promotes better growth in dry weight and standard length for all the feeding sequences tested. In addition, feeding sequences affects larval growth and survival. Best result in survival (62,81±4,77%) were obtained with high larval density and T2 feeding sequence.

Efecto de la inclusión de harinas de cangrejo de diferente origen en piensos para bocinegro (Pagrus pagrus) sobre el crecimiento, utilización de la dieta y coloración de la piel

[EN] The effect of dietary inclusion of two type of crab meal on growth, feed utilization and skin coloration performance was investigated in a growth trial with red porgy (Pagrus pagrus) of 233g initial body weight, during 6 month feeding period. High quality fish meal and fish oil diet was used as a control (Diet C). Protein of fish meal in the control was replaced by increasing dietary levels of protein derived from a river crab meal (Procamburus clarkii) (CR) and a marine crab meal (Chaceon affinis) (CM) at 10% and 20% each of them. Regarding growth results, fish fed the CM20 diet showed the highest values in absolute final weight and percent of the initial weight. For animals fed the crab meal based diets, the colour result was better than that of fish fed the control one, showing skin redness similar to that of the wild specimens. For both ingredients, increasing dietary inclusions were accompanied for an increment of the colour saturation, being in this case the obtained value for the CR meal higher than those for the CM meal. Present results indicate that crab meals used in this study are suitable as partial replacers for fish meal in diets for the red porgy.

Efecto de tres anestésicos en Haliotis tuberculata coccinea (Gastropoda) y la aplicabilidad del aceite de clavo en el cultivo de abalón

[EN]Three chemical methods for induction of relaxation in H. tuberculata coccinea (50-80mm shell length) were tested: sodium pentobarbital (60mg/l), 2-phenoxyethanol (2ml/l) and clove oil at three concentrations (0.02, 0.05 and 0,5ml/l). The time taken for animals to release from aquaria walls and recover from the anaesthetics was recorded. No mortality was observed after one week from experiment. All anaesthetics made animals release from container walls within 10-30 min, but they were ineffective as muscle relaxants, leaving the foot hard and contracted. The most effective concentration tested for clove oil was 0,5ml/l at 22ºC.

La inclusión de aceites vegetales en el pienso: Efecto sobre algunos parámetros del sistema inmune de juveniles de dorada (Sparus aurata, L.)

[ES] La escasa disponibilidad y el alto coste del aceite de pescado han impulsado a los científicos a buscar fuentes alternativas a este recurso, como por ejemplo los aceites vegetales. En este estudio hemos evaluado el efecto de dos diferentes fuentes lipídicas vegetales (lino y soja) sobre el estado de salud de la dorada. Los resultados indicaron que tanto una elevada (70%) como la total (100%) sustitución de aceite de pescado por aceites vegetales en la dieta de juveniles de dorada influyen negativamente en el crecimiento y conversión del alimento. Todas las dietas, con excepción de la del 70% de sustitución, presentaron un menor crecimiento y un peso final significativamente menor (p< 0,05) que el control. La composición lipídica dietética se reflejó en los ácidos grasos de los macrófagos del riñón anterior, aunque se observó una incorporación selectiva de ARA y EPA. La expresión de Mx en respuesta a ambos estímulos (bacteria y Poli I: C) fue homogénea en todos los grupos, pero los niveles basales fueron más altos en los peces alimentados con dieta vegetal. Este resultado podría indicar un posible efecto beneficioso de los lípidos vegetales sobre el sistema inmune de los peces.

Inmunidad humoral y celular en ganado caprino : uso de calostros alternativos, conservación e higienización del calostro y efecto de la inclusión de ácido linoleico conjugado en la dieta

Programa de Doctorada: Sanidad y patología animal.