Structure, tissue distribution and estrogen regulation of splice variants of the sea bream estrogen receptor alpha gene

Estrogen actions are mainly mediated by specific nuclear estrogen receptors (ERs), for which different genes and a diversity of transcript variants have been identified, mainly in mammals. In this study, we investigated the presence of ER splice variants in the teleost fish gilthead sea bream (Sparus auratus), by comparison with the genomic organization of the related species Takifugu rubripes. Two exon2-deleted ERα transcript variants were isolated from liver cDNA of estradiol-treated fish. The ΔE2 variant lacks ERα exon 2, generating a premature termination codon and a putative C-terminal truncated receptor, while the ΔE2,3* variant contains an in-frame deletion of exon 2 and part of exon 3 and codes for a putative ERα protein variant lacking most of the DNA-binding domain. Both variants were expressed at very low levels in several female and male sea bream tissues, and their expression was highly inducible in liver by estradiol-17β treatment with a strong positive correlation with the typical wild-type (wt) ERα response in this tissue. These findings identify novel estrogen responsive splice variants of fish ERα, and provide the basis for future studies to investigate possible modulation of wt-ER actions by splice variants.

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.

Evolution of the extracellular matrix in deuterostomes and the influence of calcitropic hormones

Tese de dout., Biologia (Biologia Molecular), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010

Recreational shore fishing in southern Portugal: biological and socio-economic aspects and perspectives for management

Although overfishing is a concern for many fish stocks, it was for a long time only associated with commercial fishing exploitation, with less or no attention being given to the recreational fisheries. Recent research has shown however that the impact of recreational fishing on particular species can be considerable, and that the recreational harvest needs to be taken into account if fisheries are to be accurately assessed and effectively managed. In Portugal, the first recreational fishing regulations were only recently implemented. However, mirroring other European countries, regulations lacked scientific support, and specific knowledge of the activity was limited to a few studies with limited coverage. This thesis aimed to characterize the biological and socioeconomic aspects of the recreational shore angling activity in southern Portugal, to investigate whether the regulations in place were adequate and effective, and to provide recommendations for improved management and conservation of the inshore fisheries resources. A combined aerial-roving survey was conducted to gather data on fishing effort, catch, fishing trips and socioeconomic aspects (including anglers’ perceptions of regulations) of the recreational angling activity. The analysis of anglers’ catches suggested that compliance with daily bag limits was high, with less than 0.5% of creels exceeding the 10 kg angler-1 day-1 bag limit. Overall, 11.5% of the retained fishes were undersized, but non-compliance with minimum size limits was found to be high for some species (e.g. seabass, 73% undersized). In terms of the impact of recreational shore angling, the total estimated catches corresponded to less than 1% of the commercial landings for the same period (shared species). However, shore angling catches for white sea bream (Diplodus sargus) were found to be considerable, corresponding to 65% of the commercial landings (39.4% of total catch). In terms of anglers’ perceptions about the recreational fishing regulations in Portugal, the present study has shown that the majority of anglers accepted the existence of some kind of SRF regulations, but in general there was a partial or total disagreement with the recreational fishing restrictions recently put in place. Most anglers perceived themselves as not being involved in the decision-making process and claimed that some restrictions lacked a meaningful rationale (e.g. prohibition of fishing from piers/jetties). Fishers’ awareness with regard to specific aspects of the restrictions (such as the rationale for minimum size limits) was found to be very limited. During the same period, catches from sport fishing competitions were examined to test for differences with the recreational activity in terms of catches, and evaluate long term trends in catch and mean size of fish. Catches of the sport fishing competitions were found to be different from those observed for recreational fishing, being dominated by different species (e.g. garfish, mullets), and suggesting different fishing strategies of the the two types of anglers. High percentages of undersized fish were observed to be captured (and retained) during the competitions (in particular seabass, with 100% undersized), probably as a result of a single allowable minimum size (AMS) of 15 cm for all species in use in competitions. Lastly, catch and release fishing experiments were carried out to assess post-release mortality of three recreationally important species: two banded sea bream Diplodus vulgaris; black sea bream Spondyliosoma cantharus; and gilthead sea bream Sparus aurata. Post-release mortalities were found to be low (0-12%). The main predictor of mortality for Sparus aurata was anatomical hooking location, with 63% of the fishes that died being deeply hooked. The results support the release of fish, either from mandatory (e.g. minimum landing sizes) or voluntary practices. In summary, this thesis has demonstrated that the impact of recreational fishing for particular species is significant and needs to be taken into account for more effective management and stock assessment purposes. It has also highlighted several management issues that should be addressed in order to promote more adequate regulations in the future and prevent noncompliance issues. A periodic monitoring of the recreational fishing activity including all fishing modes (i.e. spear fishing, boat, and shore angling) would also be beneficial to ensure a timely knowledge on the global recreational fishing activity and support future management actions.

Fish quality assessment through the application of chemico-physical, sensory and microbiological analyses

The quality of fish products is indispensably linked to the freshness of the raw material modulated by appropriate manipulation and storage conditions, specially the storage temperature after catch. The purpose of the research presented in this thesis, which was largely conducted in the context of a research project funded by Italian Ministry of Agricultural, Food and Forestry Policies (MIPAAF), concerned the evaluation of the freshness of farmed and wild fish species, in relation to different storage conditions, under ice (0°C) or at refrigeration temperature (4°C). Several specimens of different species, bogue (Boops boops), red mullet (Mullus barbatus), sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax), during storage, under the different temperature conditions adopted, have been examined. The assessed control parameters were physical (texture, through the use of a dynamometer; visual quality using a computer vision system (CVS)), chemical (through footprint metabolomics 1H-NMR) and sensory (Quality Index Method (QIM). Microbiological determinations were also carried out on the species of hake (Merluccius merluccius). In general obtained results confirmed that the temperature of manipulation/conservation is a key factor in maintaining fish freshness. NMR spectroscopy showed to be able to quantify and evaluate the kinetics for unselected compounds during fish degradation, even a posteriori. This can be suitable for the development of new parameters related to quality and freshness. The development of physical methods, particularly the image analysis performed by computer vision system (CVS), for the evaluation of fish degradation, is very promising. Among CVS parameters, skin colour, presence and distribution of gill mucus, and eye shape modification evidenced a high sensibility for the estimation of fish quality loss, as a function of the adopted storage conditions. Particularly the eye concavity index detected on fish eye showed a high positive correlation with total QIM score.

Caracterização transcricional dos genes CTR1 e ATP7B no peixe Poecilia vivipara: efeitos do cobre e da salinidade

Em peixes, o cobre (Cu) é absorvido a partir da água, via branquial, e pela ingestão de água e alimento, via gastrintestinal. Para evitar reações não específicas prejudiciais e suprir proteínas dependentes de Cu, existem transportadores específicos, como as proteínas de absorção de alta afinidade ao Cu (CTR1) e as Cu-ATPases (ATP7), que auxiliam na translocação intracelular do metal. No presente estudo, os genes CTR1 e ATP7B foram identificados em Poecilia vivipara e os seus transcritos foram quantificados por RT-qPCR nas brânquias, no fígado e no intestino de guarús expostos (96 h) ao Cu (0, 5, 9 e 20 µg/L) em água doce e salgada (salinidade 24). Foram identificadas novas sequências nucleotídicas dos genes CTR1 (1560 pb, completa) e ATP7B (617 pb, parcial), as quais tiveram altos valores de identidade com as descritas para Fundulus heteroclitus (CTR1=81%) e Sparus aurata (ATP7B=81%). A análise por RT-qPCR indicou níveis de transcrição para CTR1 e ATP7B em todos os tecidos analisados. Em guarús na água doce, a maior expressão da CTR1 e da ATP7B se deu no fígado. Em guarús na água salgada, a maior expressão da CTR1 ocorreu no intestino, enquanto a da ATP7B se deu no fígado e intestino. Na água doce, a exposição ao Cu aumentou o conteúdo branquial e hepático de Cu, diminuiu os transcritos de CTR1 e ATP7B nas brânquias e aumentou os transcritos destes genes no fígado, sem alterar o conteúdo corporal de Cu. Na água salgada, a exposição ao Cu aumentou o conteúdo de Cu e diminuiu o transcrito de ATP7B no intestino, sem alterar o conteúdo corporal de Cu nos P. vivipara. Estes resultados indicam que a homeostasia do Cu em P. vivipara envolve a redução da expressão do CTR1 e ATP7B nas brânquias (água doce) e intestino (água salgada) para limitar a absorção do Cu e o aumento da expressão destes genes no fígado (água doce) para facilitar o armazenamento e desintoxicação do Cu.

Effect of different rotifers enrichment formula feed on growth and survival of sea bream larvae ("Sparus aurata")

Universidad de Las Palmas de Gran Canaria. Facultad de Ciencias del Mar. Final assignment for the Marine Science Degree ; 2013-2014

Combined levels of carotenoids and vitamin E in diets for gilthead seabream broodstocks (Sparus aurata L.): effect on the quality of egg spawning and composition

Watanabe et al. (1991 a,b) state that, vitamin E and carotenoids perform an essential role on the quality of egg spawning. Vitamin E is one of the main nutrients for the reproduction of fish (Izquierdo et al., 2001), and it has been proved that its inclusion in diets for broodstocks favors the quality of egg spawning in several species of fish (Watanabe and Takashima,1977; Takeuchi et al., 1981; Watanabe et al., 1985, 1991 a,b; Sutjaritvongsanon, 1987; Watanabe, 1990; Schimittou, 1993; Mushiake et al., 1993; Dube, 1996; Shiranee and Natarajan, 1996; Izquierdo et al., 2001; Morehead et al., 2001; Fernández- Palacios et al., 2005). On the other hand, the carotenoids which also perform an antioxidizing function (including the protection of lipids from oxidation), have been involved in the reproductive processes of marine organisms: crustaceans (Liñan-Cabello et al., 2002), marine fish (Watanabe y Kiron, 1995; Verakunpiriya et al., 1997 a,b; Vassallo-Agius et al., 2001 a,b,c, 2002; Watanabe and Vassallo-Agius 2003) and fresh water fish (Ahmadi et al., 2006). The results of this study suggest that the recommended levels of n-3 HUFA in diets for gilthead sea bream broodstocks could be increased up to 3,5 % when supplemented jointly with carotenoids from paprika oleoresin and vitamin E, thus favoring the quality of spawning.

Efecto del contenido de DHA en el enriquecimiento de rotíferos sobre la aparición de deformidades esqueléticas en la dorada Sparus aurata (Linnaeus, 1758)

Since sudden mortalities and increased skeletal deformities in gilthead seabream juveniles are currently found in production hatcheries, this study aimed to evaluate the contribution of essential fatty acids, particularly DHA over early feed quality, larval growth, survival and the apparition of skeleton abnormalities in highly commercial interest specie such as Sparus aurata. Sea bream larvae were reared under intensive conditions and fed rotifers enriched with two different enrichment emulsions differing in DHA content. Thus, essential fatty acid composition of rotifers, showed fatty acid profile of enrichment emulsions. The increase in rotifers DHA (10.0 to 25.4% TFA) were also reflected in a higher DHA content in the FA composition of larval fed this rotifers (13.0 to 20.4% TFA) when these preys were the main source of food (14dah). Survival at 50 days after hatching (13.9±4.3) and growth evolution from 3dah until day 50, were similar in both treatments, whereas bone malformations, particularly opercula reduction, and jaw deformities were higher in higher DHA rotifers fed larvae.

Identification of formalin-preserved eggs of red sea bream (Pagrus major) (Pisces: Sparidae) using monoclonal antibodies

Catches of important commercial fish such as red sea bream, flat fish, and yellowtail are decreasing in Japan. In order to sustain these species it is especially important that their distribution and biomass at all life stages are known. However, information on the early life stages of these species is limited because identifying the eggs and larvae of such fish is sometimes extremely difficult.

Wadge Bank trawl fishery studies. Pt. 4. An analysis of the length frequency measurements of the sea bream (Lethrinus nebulosus) made in 1949 and 1953 to 1958

Length frequency distributions of the sea bream collected during the period 1953 to 1958 have been analysed. The increase in average sizes of the sea bream with depth suggests a movement to deeper waters with increase in size. By numbers, the sea bream is more abundant between 21 and 30 fathoms than in deeper areas. The recruitment was continuous and regular. There is no sign of entry or progression of a dominant brood throughout the period under study. Length frequency distribution shows three distinct modes. The first mode occurs regularly but does not progress beyond 40cm, recruitment being balanced by natural and fishing mortality. The other two which are not regular are probably the result of fishing outside regular areas. Short sections of “growth” lines which fit into one another when extrapolated, are evident. The larger lines obtained by extrapolation are parallel to one another. These tentative "growth lines" indicate that this species which enters the fishing grounds, when 15 cm or larger in length are exploited by the trawl fishery for a period of three to four years. This species appears to be six months old when it enters the fishing grounds and increases in length by about 37.5 cm in the next 30 months. Later growth slows down. The average size of the specimens sampled continued to get smaller from 1953 till 1957. It is shown that this reduction in size is due to increased fishing effort.

Influences of dietary lipid and phosphorus levels on retention and excretion of phosphorus and nitrogen in fingerlings red sea bream, Pagrus major

A laboratory based 2x3 factorial experiment was conducted for 12 weeks to investigate the influences of dietary lipid and phosphorus (P) levels on retention and excretion of phosphorus and nitrogen (N) in fingerling red sea bream. Two levels of lipid (210 and 260 g/kg) and three levels of phosphorus (17, 14 and 12 g/kgˉ¹) in the dry diets were tested. Duplicate groups of 25 red sea bream (average weight 3.74±0.07 g) per 60L glass tank were fed experimental diets three times a day near to satiation level at 22 to 28°C water temperature. A reduction in dietary fish meal from 500 to 300 g/kg dry diet, corresponding to a supplementation in both dietary lipid and P resulted in significant increase in both P and N retention which resulted in the reduction of their excretion by red sea bream. The overall results of the present study demonstrated that both lipid and phosphorus supplementation are necessary for developing less-polluting feed which in turn, reduce fish meal level in the diet of fingerling red sea bream. Further studies in this regard with different size and age groups of red sea bream are warranted.

Cadmium toxicity to embryonic-larval development and survival in red sea bream Pagrus major

At 18 degrees C and 33 psu, 24 and 48 h LC50 values of cadmium (Cd) for red sea bream Pagrus major embryos were 9.8 and 6.6 mg l(-1), respectively, while 24,48, 72, and 96 h LC50 values for larvae were 18.9,16.2, 8.0, and 5.6 mg l(-1), respectively, indicating that embryos were more sensitive to Cd toxicity than larvae. Cd concentrations at >= 0.8 mg l(-1) led to low hatchability (0-90% in >= 0.8 mg l(-1) solutions vs. 97-100% in lower ones), delay in time to hatch, high mortality (38-100% vs. 1-10%), morphological abnormality (42-100% vs. 1-10%), reduced length (3.55-3.60 vs. 3.71-3.72 mm) in the embryos and larvae. They were Cd concentration dependent and potential biological significant endpoints for assessing the risk of Cd to aquatic organisms. Heart beat and yolk absorption of the larvae were significantly inhibited at some high concentrations but they were not as sensitive as other endpoints to Cd exposure. (C) 2008 Elsevier Inc. All rights reserved.

Preliminary studies on the vitrification of red sea bream (Pagrus major) embryos

The objective was to identify an appropriate cryoprotectant and protocol for vitrification of red sea bream (Pagrus major) embryos. The toxicity of five single-agent cryoprotectants, dimethyl sulfoxide (DMSO), propylene glycol (PG), ethylene glycol (EG), glycerol (GLY), and methyl alcohol (MeOH), as well as nine cryoprotectant mixtures, were investigated by comparing post-thaw hatching rates. Two vitrifying protocols, a straw method and a solid surface vitrification method (copper floating over liquid nitrogen), were evaluated on the basis of post-thaw embryo morphology. Exposure to single-agent cryoprotectants (10% concentration for 15 min) was not toxic to embryos, whereas for higher concentrations (20 and 30%) and a longer duration of exposure (30 min), DMSO and PG were better tolerated than the other cryoprotectants. Among nine cryoprotectant mixtures, the combination of 20% DMSO + 10% PG + 10% MeOH had the lowest toxicity after exposure for 10 min or 15 min. High percentages of morphologically intact embryos, 50.6 +/- 16.7% (mean +/- S.D.) and 77.8 +/- 15.5%, were achieved by the straw vitrifying method (20.5% DMSO + 15.5% acetamide + 10% PG, thawing at 43 degrees C and washing in 0.5 M sucrose solution for 5 min) and by the solid surface vitrification method (40% GLY, thawing at 22 degrees C and washing in 0.5 M sucrose solution for 5 min). After thawing, morphological changes in the degenerated embryos included shrunken yolks and ruptured chorions. Furthermore, thawed embryos that were morphologically intact did not consistently survive incubation. (C) 2007 Elsevier Inc. All rights reserved.