Olfactory sensitivity of the marine flatfish Solea senegalensis to conspecific body fluids.

Chemical communication is better understood in freshwater fish than marine fish. The Senegalese sole (Solea senegalensis) is a marine flatfish wherein one of the problems in aquaculture is the poor reproductive performance of hatchery-bred males. Is chemical communication involved in the reproduction of this species? Urine, intestinal fluid and mucus samples were taken from adult fish (wild-caught and hatchery-bred) over the spawning season (March-May), and assessed for olfactory potency using the electro-olfactogram (EOG). The effect of stimulation of the olfactory system with adult female urine on circulating luteinizing hormone (LH) levels was also tested in males. Intestinal fluid and urine were potent olfactory stimuli for both juvenile and adult conspecifics, evoking large-amplitude, concentration-dependent EOG responses, with thresholds of detection at approximately 1:106 However, the amplitude of the response to urine depended on the sex and state of maturity of both the donor and the receiver. Most olfactory activity could be extracted by C18 solid-phase cartridges. Urine from mature females evoked a slight, but significant, increase in circulating LH levels in mature males 30 min after exposure. Furthermore, the olfactory potency of urine differed between wild-caught and hatchery-bred fish; however, contrary to expectations, urine from wild-caught females was less potent than that from hatchery-bred females. Taken together, these results strongly suggest that faeces- and urine-released odorants are involved in reproduction in the Senegalese sole, and establish a basis for further investigation into pheromonal communication in marine teleosts.

[Estimation of the daily nutrients distribution in the Spanish standard diet]. / ESTIMACIÓN DE LA DISTRIBUCIÓN DIARIA DE NUTRIENTES EN LA DIETA ESTÁNDAR EN ESPAÑA.

Based on the raw data from the Spanish intake, have made the necessary changes and groupings to establish nutritional content per serving as percentages, regarding the total daily intake of each individual surveyed (n = 3000). Also, it was found the effect of the rating factors (sex, age and location) on the distribution of these percentages. The result indicates that individuals below 25 year should be considered as different groups, front those above that age; and locality effect (treated as random factor rather than fixed) causes differences in the distribution of nutrients between food daily intakes. However, the sex was was not relevant to the anecdotal footage found in statistically significant differences. Percentage distribution of individual nutrients between different food outlets is proposed.

A partir de datos de consumo alimentario de España se han realizado las transformaciones y agrupaciones necesarias para establecer los contenidos nutricionales por toma, en forma de porcentajes, respecto a la ingesta total diaria de cada individuo encuestado (n = 3000). Así mismo, se ha comprobado el efecto de los factores de clasificación (sexo, edad y localidad) sobre la distribución de dichos porcentajes. El resultado del estudio estadístico indica que se deben considerar como grupos diferentes los individuos por debajo de 25 años respecto a los que superan esa edad y que el efecto localidad (entendido como aleatorio y no como fijo) ocasiona diferencias en la distribución de nutrientes entre las tomas de alimentos del día. En cambio, el factor sexo no resultó relevante al encontrarse en tomas anecdóticas las diferencias estadísticamente significativas. Se propone una distribución porcentual de nutrientes concretos entre las diferentes tomas de alimentos.

Estimación de la distribución diaria de nutrientes en la dieta estándar en España / Estimation of the daily nutrients distribution in the Spanish standard diet

A partir de datos de consumo alimentario de España se han realizado las transformaciones y agrupaciones necesarias para establecer los contenidos nutricionales por toma, en forma de porcentajes, respecto a la ingesta total diaria de cada individuo encuestado (n = 3000). Así mismo, se ha comprobado el efecto de los factores de clasificación (sexo, edad y localidad) sobre la distribución de dichos porcentajes. El resultado del estudio estadístico indica que se deben considerar como grupos diferentes los individuos por debajo de 25 años respecto a los que superan esa edad y que el efecto localidad (entendido como aleatorio y no como fijo) ocasiona diferencias en la distribución de nutrientes entre las tomas de alimentos del día. En cambio, el factor sexo no resultó relevante al encontrarse en tomas anecdóticas las diferencias estadísticamente significativas. Se propone una distribución porcentual de nutrientes concretos entre las diferentes tomas de alimentos (AU)

Based on the raw data from the Spanish intake, have made the necessary changes and groupings to establish nutritional content per serving as percentages, regarding the total daily intake of each individual surveyed (n = 3000). Also, it was found the effect of the rating factors (sex, age and location) on the distribution of these percentages. The result indicates that individuals below 25 year should be considered as different groups, front those above that age; and locality effect (treated as random factor rather than fixed) causes differences in the distribution of nutrients between food daily intakes. However, the sex was not relevant to the anecdotal footage found in statistically significant differences. Percentage distribution of individual nutrients between different food outlets is proposed (AU)

Effects of graded levels of arachidonic acid on the reproductive physiology of Senegalese sole (Solea senegalensis): Fatty acid composition, prostaglandins and steroid levels in the blood of broodstock bred in captivity.

Previous studies on Senegalese sole (Solea senegalensis) indicated that cultured broodstock (first generation, G1) have lower tissue levels of arachidonic acid (20:4n-6, ARA) than wild counterparts. ARA is metabolized to form prostaglandins (PGs) that are involved in steroid production and follicle maturation in fish. In the present study the effects of different dietary levels of ARA on blood lipid and fatty acid composition, prostaglandin (PGF2α, PGF3α, PGE2 and PGE3) levels and plasmatic steroid levels (11-ketotestosterone, 11-KT, testosterone, T and estradiol, E2) in G1 Senegalese sole were studied. For this purpose, 12 groups of ten fish (1:1 male and female), were fed six diets (each diets was fed to two groups) with different dietary ARA levels over nine months (diets A=0.7, B=1.6, C=2.3, D=3.2, E=5.0, F=6.0% ARA). ARA and CHOL levels in blood showed a significant increase in an ARA dose related manner (P<0.05) whereas EPA and EPA/ARA ratio were reduced. In males, steroid (11-KT and T) levels increased significantly with increasing dietary ARA in a dose dependent manner, whereas in females E2 did not show any change related to dietary ARA content. Plasma concentration of 3-series PGs (i.e., PGE3 and PGF3α) were reduced in parallel to increased ARA levels in blood (P<0.05) and levels of PGs 3-series were always higher than 2-series PGs (PGE2 and PGF2α). In conclusion there is an effect of dietary ARA on steroid production of Senegalese sole males, which might have important consequences in the reproduction of cultured fish.

Reproductive development, GnRHa-induced spawning and egg quality of wild meagre (Argyrosomus regius) acclimatised to captivity.

The objective of the study was to acclimatise wild-caught meagre (Argyrosomus regius) to captivity to produce viable eggs for aquaculture production. Twelve meagre (3 males and 9 females, mean weight = 20 ± 7 kg) were caught and transported to a land-based facility on 26 October 2006. During, March to June 2007, all three males were spermiating and five of the nine females were in vitellogenesis with mean maximum oocyte diameter ≥550 µm. No spontaneous spawning was observed. Two hormone treatments, either a single injection of gonadotropin-releasing hormone agonist (GnRHa, 20 µg kg(-1) for females and 10 µg kg(-1) for males) or a slow-release implant loaded with the same GnRHa (50 µg kg(-1) for females and 25 µg kg(-1) for males), were used to induce spawning on three different dates on 26 March 2007, 4 May 2007 and 18 April 2008. From each spawning event, the following parameters were determined: fecundity, number of floating eggs, egg size, fertilisation and hatching success, unfed larval survival, and proximal composition and fatty acid profile of the eggs. In 2007, two females that were injected on 26 March and 4 May spawned a total of 5 times producing 9,019,300 floating eggs and a relative fecundity of 198,200 eggs kg(-1) and two different females that were implanted on the same dates spawned 14 times producing 12,430,000 floating eggs and a relative fecundity of 276,200 eggs kg(-1). In 2008, a pair that was implanted spawned five times producing a total of 10,211,900 floating eggs and a relative fecundity of 527,380 eggs kg(-1). The latency period was 48-72 h. Parameters were compared between hormone treatments, date of hormone induction and parents determined by microsatellites. Percentage hatch and egg size were 70 ± 0.3% and 0.99 ± 0.02 mm, respectively, for GnRHa-implanted fish and were significantly higher (P < 0.05) compared to 30 ± 0.3% and 0.95 ± 0.03 mm, respectively, for injected fish. Few differences were observed in proximal composition and fatty acid profile and for all spawns mean (% dry weight) lipid content was 17.3 ± 3.0%, carbohydrate was 4.4 ± 1.9% and protein was 31.5 ± 6.4% and the essential fatty acids: Arachidonic acid (ARA, 20:4n-6) ranged between 0.9 and 1% (of total fatty acids), eicosapentaenoic acid (EPA 20:5n-3) 7.7-10.4% and docosahexaenoic acid (DHA 22:6n-3), 28.6-35.4%. All good quality spawns were obtained in the second and/or third spawn after GnRHa treatment, whereas all bad quality spawns were obtained either on the first spawn or after the fifth spawn. Both spawning protocols gave commercially viable (1,000,000+) numbers of good quality eggs that could form the basis of a hatchery production.