The influence of organic versus conventional feeding on the growth and survival of gilthead sea bream Sparus aurata L. juveniles

Sparus aurata specimens of 11 months of age (mean weight: 90.2 g, mean length: 18.3 cm) were classified in two diet groups: one control group was fed with conventional diet, and one experimental group was fed with an organic diet. The body and muscle parameters were studied at 0, 41 and 71 days of the experiment. The results showed the highest values of body length and weight as well as the best biological feed conversion rates in the organic group. The transverse area of white muscle, the hyperplasia and the muscle fibres density were also higher in the organic than in the conventional group (P>0.05). In contrast, hypertrophy was greater in the conventional than in the organic group (P<0.05). Survival was 100% in both groups. In conclusion, the organic feeding regime was more favourable for growth than conventional feeding.Versión del edito

Long-term Effects of the Larval Photoperiod on the Subsequent Growth of Shi Drum Umbrina cirrosa L. Specimens and the Fillet Texture at Commercial Size

Three groups of shi drum Umbrina cirrosa L. were reared with different photoperiod regimes: 24L, 12L:12D and 16L:8D (natural photoperiod) during the larval period and then all of them were transferred to a natural photoperiod. At 11.8 and 20 months of age, the body growth and the muscle parameters reached the highest values in the 24L and 12L:12D groups. The 16L:8D group showed the lowest growth. When comparing 24L with 12L:12D, the highest number of white fibres was found in the 24L group, whereas the greatest fibres size was reached in the 12L:12D group. Commercial size (28-30 cm; 290-340 g) was reached at 20 months of age in the 24L and 12L:12D groups, but at 23 months in the 16L:8D group. When comparing the three groups at the commercial stage, the larval photoperiod effect was still observed, such that the highest fibres number was again found in the 24L group, whereas the greatest fibres size was reached in the 12L:12D group. The highest values of textural hardness were observed in the 16L:8D and 24L groups. A nutritional analysis was carried out in the 16L:8D group, which showed the following percentage values: 2.66, 21.2, 74.4, and 1.46 of fat, protein, moisture and ash, respectively.0,591

DATOS BIOMÉTRICOS Y DE COMPOSICIÓN EN LUBINA DE TAMAÑO COMERCIAL (Dicentrarchus labrax L.) CULTIVADA A DIFERENTES TEMPERATURAS

Se estudió el crecimiento y algunos parámetros somatométricos (longitud total, a la horquilla, estándar, cefálica, y de la línea lateral; altura dorsal superior, anal, y dorsal inferior; índice de condición, cefálico, de compacidad, gonadosomático, hepatosomático, digestosomático, bazosomático, grasosomático y fracción comestible), así como la composición corporal, en lubinas de un peso de 350 g mantenidas a diferentes temperaturas desde la fertilización hasta el tamaño comercial. Los dos lotes sólo presentaron diferencias significativas en el contenido en cenizas (P0,05), que fue mayor en la población cultivada a alta temperatura. Se discutieron los resultados en relación con la temperatura. Estos resultados mostraron la escasa influencia del método de cultivo, lo que puede ser de interés por su posible efecto sobre la calidad final del producto.Biometric and composition data in sea bass, Dicentrarchus labrax (Linnaeus, 1758), of commercial size cultivated at different temperatures. Some somatometric parameters (total, fork, standard, head, and lateral line length; superior dorsal, anal, and inferior dorsal height; condition, cranial, compactness, gonadosomatic, hepatosomatic, digestosomatic, spleensoomatic, perivisceral fat and dressing index) and body composition of 350 g sea bass cultured under different temperatures from fertilization to commercial size were studied. We found significative differences (P0,05) between both groups only in ash content which was higher in the fish cultivated at high temperature. The results related to temperature are discussed. These data showed that there is no influence of culture temperature on characteristics and quality of the final product and that this fact can be of interest from the point of view of the aquaculture commercialization.CICYT. Proyecto AGL2000-1738-C03-0

Estudio de la musculatura axial en lubina salvaje y lubina atlántica cultivada, Dicentrarchus labrax L., de talla comercial. I: Estudio en fresco.

En este trabajo se realiza un estudio comparativo de la musculatura de la lubina, Dicentrarchus labrax L., procedente del medio natural (salvajes) y lubina de origen Atlántico cultivada bajo condiciones naturales de temperatura y fotoperiodo y alimentada con dietas artificiales. Se estudiaron un total de 25 ejemplares de tamaño comercial: 14 salvajes y 11 cultivados. Se midieron sus longitudes y pesos y se realizó una sección transversal en la zonal caudal (a nivel de la apertura anal) y en la zona craneal (a nivel del 4º radio de la aleta dorsal) con el fin de estudiar los siguientes parámetros: área transversal del total del miotomo y del músculo blanco, área y número de fibras blancas. Los ejemplares salvajes mostraron un mayor tamaño del área total del miotomo que los mantenidos a temperatura ambiente, aunque estas diferencias no fueron estadísticamente significativas. Asímismo, la constitución interna del miotomo fue diferente entre ambas poblaciones, de tal forma que los ejemplares de lubina salvaje presentaron un mayor número de fibras que los ejemplares cultivados de lubina atlántica (p<0.05). Por el contrario, el área de las fibras fue mayor en lubina atlántica (p<0.05). Este estudio pone de manifiesto que las condiciones medioambientales y el origen genético influyen sobre los mecanismos de crecimiento y la constitución fibrilar, lo que puede incidir en la calidad final del producto.MCYT. Proyecto AGL2000-1738-C03-0

Effect of incubation and rearing temperatures on white muscle growth of the common dentex Dentex dentex (Linnaeus, 1758)

In order to determine the impact of temperature on axial muscle growth of common dentex Dentex dentex (Linnaeus, 1758) eggs from the same spawn were divided into four batches and reared under different temperature combinations. The cross-sectional area of white muscle and the number and average area of the white muscle fibres were quantified at different stages of larval development. Our results show that, in newly hatched larvae, slight changes in incubation temperature (≈ 2 ºC) produced significant differences in the cross-sectional area of white muscle, which was greater in the group incubated at ambient temperature. As the larval development advanced, the muscle growth parameters showed the highest values in larvae maintained in constantly heated water.Se pretende valorar el efecto de la temperatura sobre el crecimiento de la musculatura axial del dentón Dentex dentex (Linnaeus, 1758). Para ello se incubó una puesta distribuida en cuatro lotes que fueron sometidos a combinaciones de temperatura. En distintos momentos del desarrollo larvario se cuantificó el área total del miotomo, el área de las fibras blancas y el número de fibras blancas de la sección transversal. Los resultados han demostrado que modificaciones pequeñas en la temperatura de incubación (≈ 2 ºC) producen diferencias significativas en el área transversal total del músculo blanco de las larvas recién eclosionadas, diferencias que son mayores en los ejemplares incubados a temperatura ambiente. A medida que avanza el desarrollo de las larvas se produce una inversión y pasan a ser mayores los parámetros de crecimiento muscular en las larvas mantenidas siempre en agua que es calentada.Instituto Español de Oceanografí

Influence of the stocking density on the growth, feeding, survival rate and muscle cellularity of juvenile specimens of common name shi drum, Umbrina cirrosa L.

Common name Umbrina cirrosa specimens (mean weight 9.5 g, mean length 9 cm) were categorized in three densities (4, 9 and 15 kg m-3 ) in order to study the influence of stocking density on the growth, survival rate and feed conversion rates. The body and muscle parameters were studied at 0, 43 and 84 days of the experiment. After 43 days, the highest body parameters values (body length and weight) were found in specimens reared at 9 kg m-3 , followed by the specimens reared at 4 kg m-3 , showing the specimens reared at 15 kg m-3 the lowest growth. These results showed a negative effect of high density on the growth, being the intermediate density (9 kg m-3 ) the most favorable density for the growth at this stage. Muscle cellularity was different among the groups, being the hypertrophy values higher at high density of rearing (15 kg m-3 ) than at 4 and 9 kg m-3 . In contrast, the hyperplasia was higher at 4 kg m-3 than in the rest of densities. The group reared at 9 kg m-3 showed intermediate values of hypertrophy and hyperplasia. At 84 days of the experiment, the muscle cellularity was similar at 4 and 9 kg m-3 , this indicating a compensatory hypertrophic growth at 4 kg m3 . The highest values of body weight were reached at 9 kg m-3 . Moreover, the feed conversion rates and the percentage of survival rate were better at 9 than at 4 kg m-3 .S

Effect of the photoperiod on growth, survival and inflation of the swim bladder in dentex (Dentex dentex L.) larvae

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Influence of the stocking density on the growth, feeding, survival rate and muscle cellularity of juvenile specimens of common name shi drum, Umbrina cirrosa L.

Common name Umbrina cirrosa specimens (mean weight 9.5 g, mean length 9 cm) were categorized in three densities (4, 9 and 15 kg m-3 ) in order to study the influence of stocking density on the growth, survival rate and feed conversion rates. The body and muscle parameters were studied at 0, 43 and 84 days of the experiment. After 43 days, the highest body parameters values (body length and weight) were found in specimens reared at 9 kg m-3 , followed by the specimens reared at 4 kg m-3 , showing the specimens reared at 15 kg m-3 the lowest growth. These results showed a negative effect of high density on the growth, being the intermediate density (9 kg m-3 ) the most favorable density for the growth at this stage. Muscle cellularity was different among the groups, being the hypertrophy values higher at high density of rearing (15 kg m-3 ) than at 4 and 9 kg m-3 . In contrast, the hyperplasia was higher at 4 kg m-3 than in the rest of densities. The group reared at 9 kg m-3 showed intermediate values of hypertrophy and hyperplasia. At 84 days of the experiment, the muscle cellularity was similar at 4 and 9 kg m-3 , this indicating a compensatory hypertrophic growth at 4 kg m3 . The highest values of body weight were reached at 9 kg m-3 . Moreover, the feed conversion rates and the percentage of survival rate were better at 9 than at 4 kg m-3

Effect of sodium alginate dietary in body parameters and muscle growth of gilthead sea bream, Sparus aurata L.

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