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The red porgy (Pagrus pagrus) and the common dentex (Dentex dentex) are Sparidae species of high commercial value, traded in the Greek market. In some cases, fish species identification from Greek fisheries is difficult for the consumer due to the strong morphological similarities with their imported counterparts or closely related species such as Pagrus major, Pagrus caeroleustictus, Dentex gibbosus and Pagellus erythrinus, especially when specimens are frozen, filleted or cooked. Techniques based on DNA sequencing, such as COI barcoding, accurately identify species substitution incidents; however, they are time consuming and expensive. In this study, regions of mtDNA were analyzed with RFLPs, multiplex PCR and HRM in order to develop a rapid method for species identification within the Sparidae family. HRM analysis of a 113 bp region of cytb and/or a 156 bp region of 16s could discriminate raw or cooked samples of P. pagrus and D. dentex from the aforementioned closely related species and P. pagrus specimens sampled in the Mediterranean Sea when compared to those fished in the eastern Atlantic. HRM analysis exhibited high accuracy and repeatability, revealing incidents of mislabeling. Multiple samples can be analyzed within three hours, rendering this method a useful tool in fish fraud monitoring. [ABSTRACT FROM AUTHOR]

Abstract Background Soybean is a common alternative protein source of plant origin in aquafeeds as it has a reasonably balanced amino acid profile and is widely available. This study aimed to investigate the influence of partial substitution of fish meal with soy meal on cytoprotective pathways and apoptosis in the digestive system of common dentex (Dentex dentex), using the activation of Hsp70, p38 MAPK, Bcl-2 and caspase-3. The experimental approach involved feeding of common dentex with three isoprotein and isoenergetic diets that contained fish meal as a protein source (FM), partial replacement of fish meal by soy meal 25% (SM25) and 40% (SM40) for 3 months. Results The SM40 diet induced Hsp70 activation only in the middle part of intestine. On the other hand, both SM25 and SM40 diets diminished the phosphorylation of p38 MAPK in the anterior and the middle part of intestine, whereas only SM25 induced p38 MAPK phosphorylation in the stomach. Moreover, a decrease in the levels of caspase-3 activity was observed in the middle and posterior intestine, as well as in the stomach after feeding with SM25 diets. Furthermore, Bcl-2 levels were increased by SM40 in the anterior and by SM25 in the middle part of intestine. Conclusions SM25 and SM40 diets elicited a tissue and soy concentration specific cellular and cell protective response in the different parts of the digestive tract in common dentex.

Abstract: Microorganisms present in the rearing water colonize the gut of first feeding larvae and represent the first barrier against opportunistic pathogens. The aim of the experiments presented herein was to standardize a protocol for the management of rearing water and microalgae suitable for the larval rearing of common dentex. In Experiment 1, bacteria–algae interactions were tested using a monospecific microalgal community, Tetraselmis chuii, suitable for nutritional experiments and with known antibacterial activity. In Experiment 2, the evolution of the bacterial community and larval performance (growth and survival) were monitored daily, in three conditions: (1) mature water: T. chuii was added 5 d before the rearing of common dentex larvae, (2) green water: T. chuii was added 1 d before, and (3) clear water: no T. chuii addition. The results show the influence of the presence of T. chuii on the evolution of the bacterial communities, both in terms of bacterial density and morphology, and indicate green water is the most suitable water treatment for management of larval rearing for common dentex. [ABSTRACT FROM AUTHOR]

The common dentex, Dentex dentex, is a fish species which inhabits marine environments in the Mediterranean and Northeast Atlantic regions. This is an important species from an ecological, economic and conservation perspective, however critical information on its population genetic structure is lacking. Most samples were obtained from the Mediterranean Sea (17 sites) with an emphasis around Corsica (5 sites), plus one Atlantic Ocean site. This provided an opportunity to examine genetic structuring at local and broader scales to provide science based data for the management of fishing stocks in the region. Two mitochondrial regions were examined (D-loop and COI) along with eight microsatellite loci. The COI data was combined with publicly available sequences and demonstrated past misidentification of common dentex. All markers indicated the absence of population genetic structure from the Bay of Biscay to the eastern Mediterranean Sea. Bayesian approaches, as well as the statistical tests performed on the allelic frequencies from microsatellite loci, indicated low differentiation between samples; there was only a slight (p = 0.05) indication of isolation by distance. Common dentex is a marine fish species with a unique panmictic population in the Mediterranean and likely in the Atlantic Ocean as well. [ABSTRACT FROM AUTHOR]

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Background: Soybean is a common alternative protein source of plant origin in aquafeeds as it has a reasonably balanced amino acid profile and is widely available. This study aimed to investigate the influence of partial substitution of fish meal with soy meal on cytoprotective pathways and apoptosis in the digestive system of common dentex (Dentex dentex), using the activation of Hsp70, p38 MAPK, Bcl-2 and caspase-3. The experimental approach involved feeding of common dentex with three isoprotein and isoenergetic diets that contained fish meal as a protein source (FM), partial replacement of fish meal by soy meal 25% (SM25) and 40% (SM40) for 3 months. Results: The SM40 diet induced Hsp70 activation only in the middle part of intestine. On the other hand, both SM25 and SM40 diets diminished the phosphorylation of p38 MAPK in the anterior and the middle part of intestine, whereas only SM25 induced p38 MAPK phosphorylation in the stomach. Moreover, a decrease in the levels of caspase- 3 activity was observed in the middle and posterior intestine, as well as in the stomach after feeding with SM25 diets. Furthermore, Bcl-2 levels were increased by SM40 in the anterior and by SM25 in the middle part of intestine. Conclusions: SM25 and SM40 diets elicited a tissue and soy concentration specific cellular and cell protective response in the different parts of the digestive tract in common dentex. [ABSTRACT FROM AUTHOR]

The common dentex, Dentex dentex , is an iconic marine coastal fish of the Mediterranean Sea. Despite its economic and ecological importance, data on the population structure of this species are still very limited. The aim of this study was to identify the stock structure of the common dentex at relatively fine spatial scale around Corsica Island, using a combination of markers that have different spatial and temporal scales of integration: microsatellite DNA markers, otolith shape analysis and parasites communities. Microsatellite analysis indicated that there was no significant genetic differentiation in D . dentex between the four sampling sites around Corsica. Otolith shape analysis suggests one potential distinct population unit of D . dentex centered in one site (Cap Corse) varying in their degree of differentiation from those in the other zones. Multivariate analysis on parasite abundance data highlights to a lower extent two sites (Bonifacio and Galeria) with some connectivity between adjacent zones. The combination of these three markers together highlights the resulting three sites while giving complementary insights and an opportunity to compare their utility and potential to understand population interactions. A complex population structure around Corsican coasts is then proposed, providing a new perspective on common dentex fishery stock conservation and management strategies. [ABSTRACT FROM AUTHOR]

We investigated the nutritional quality of commercially important farmed fish species: sea bream (Sparus aurata), sea bass (Dicentrarchus labrax), dentex (Dentex dentex), and turbot (Scophthalmus maximus). The omega-3 fatty acid content of dentex was twice as high as that of any other fish species, and its eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid contents were 2-4 times higher. The recommended n-3/n-6 ratio was present in all the fish species, but the recommended polyunsaturated/saturated fatty acid ratio was not present in the turbot. All the fish species, except turbot, met the recommended atherogenic index, thrombogenic index, and ratio of hypocholesterolaemic to hypercholesterolaemic fatty acids, whereas the highest flesh lipid quality value was observed in the dentex. [ABSTRACT FROM AUTHOR]

This study examined the stomach contents of 230 individuals out of 439 samples obtained from commercial fishermen between January 2013 and March 2014 from a trawler using trawl bags with a full cod-end mesh size of 44 mm. It was found that 216 samples were full and the stomach fullness index was estimated at 93.9%. The varying diet composition of the species was determined by estimating the percentage numerical composition (N%), frequency of occurrence (F%), gravimetric composition (W%) and the index of relative importance (IRI%). Diversity (Shannon index), richness (Margalef index) and similarity (Bray-Curtis index) of the catches in different seasons were calculated using the Biodiversity Professional (Version 2) software. Three major groups were identified in the catches: Crustacea, Mollusca and Teleostei. At least 17 different prey groups were identified. With regard to the diversity of consumed prey, the winter (1.204), autumn (1.079) and spring (1.000) seasons were characterized by a medium level of diversity, summer (0.699) - by a low level of diversity. However, the richness of prey does not show seasonal differences. As indicated by the Bray-Curtis index, the highest similarity between the prey groups was observed between the autumn and winter seasons, at 81.61%. [ABSTRACT FROM AUTHOR]

As the world's fastest ongrowing sector in food production, aquaculture has remarkable priority and needs technological improvements and new candidate fish species to overcome some limitation factors. Considering these issues, this study based on determining the flesh quality in terms of nutrient and mineral element composition of two potential fish species, common dentex (Dentex dentex) and greater amberjack (Seriola dumerili), in recirculation aquaculture system (RAS). On the nutrient basis, the dry matter content of 28.82% and fillet yield with a value of 53.28% of Dentex dentex were found significantly higher than (P<0.05) Seriola dumerili. Crude protein and lipid values demonstrated slight but insignificant differences between the species. Among the macro elements of K and Mg and micro elements of Cr, Mn and Ni were noticeably higher in common dentex than greater amberjack, but Zn level was present almost double amount in amberjack (P<0.05). [ABSTRACT FROM AUTHOR]

Common dentex ( Dentex dentex ) is an appreciated carnivorous fish with high growth rate and life cycle adaptable to existing farming techniques. Since the use of carbohydrates is an economic and sustainable alternative for a protein-sparing effect, the study of how this macronutrient affects the welfare of carnivorous species must be studied. The aim of the present study was to evaluate the effects of different types and levels of carbohydrates on common dentex oxidative status. Nine isonitrogenous (43%) and isoenergetic (22 MJ kg − 1 ) diets were formulated combining three types (pregelatinized starch-PS, dextrin-Dx and maltodextrin-Mx) and three levels (12, 18 and 24%) of carbohydrates. The activities of catalase-CAT, superoxide dismutase-SOD, glutathione peroxidase-GPX, glutathione reductase-GR and glucose 6-phosphate dehydrogenase-G6PDH, SOD isoenzymatic profile, lipid peroxidation-LPO and protein oxidation-PO were determined in liver and white muscle. SOD and CAT were not affected. GPX in liver and white muscle and GR in liver increased at higher inclusion carbohydrates levels. The lowest levels of GR and G6PDH in both tissues and LPO in liver were observed in maltodextrin groups. No significant effects by carbohydrate source were observed in liver PO and white muscle LPO. Regarding carbohydrate level effect, 18% and 24% dietary inclusion level decreased LPO in white muscle and PO in liver. LPO in liver was also decreased at 24% inclusion level. Altogether, results indicate the use of carbohydrates as an alternative energy source does not produce negative effects on oxidative status of common dentex, on the contrary, even contribute to their oxidative protection. [ABSTRACT FROM AUTHOR]

Larval fish have a relatively poorly developed immune system and hence they primarily rely on non-specific immune responses produced in the skin and gut. This study aims to illustrate the fine structure of gut development in common dentex (Dentex dentex) larvae and determine the initiation of pinocytic activity, which is an important early non-specific immune response in fish intestines, during various live-food feeding stages (yeast enriched rotifer, Artemia nauplii and metanauplii) from hatching (D0) to 25 days after hatching (D25) by using transmission electron microscopy (TEM). A total of 54 larvae were sampled and examined with electron microscopy. The results show that hind-gut intestine enterocytes have morphological features which suggest they play a role in absorption and intracellular digestion of nutrients in fish. The presence of vigorous pinocytic activity in the Artemia feeding stage between 17-25 days after hatching is evidence for the development of a nonspecific immune system. In the present study, the ultrastructural gut development of cultured common dentex was investigated for the first time and the data reported in this study may provide additional fundamental knowledge for improving larval rearing success in common dentex culture. [ABSTRACT FROM AUTHOR]

Abstract The egg quality of two common dentex captive broodstocks were monitored for two consecutive years during their natural spawning season. Volume of spawned eggs, volume of buoyant eggs, fertilization rate, egg weight, hatching rate and mortality of larvae were recorded. According to the volume of spawned eggs, the ratio of buoyant eggs spawned, the number of spawning days and the fertilization rate pointed to an improvement from Year 1 to Year 2. But data on hatching rate and larval mortality lead to the opposite conclusion. Highlights • Two common dentex captive broodstocks have been monitored during their natural spawning season for two consecutive years. • The quality of the spawned eggs has been assessed using different quality criteria based on egg production or larval performance. • Criteria used for assessing the spawning quality lead to different conclusions. • In conclusion, all criteria should be used in order to obtain a reliable assessment, including criteria based on larval performance. [ABSTRACT FROM AUTHOR]

Based on light and scanning electron microscopical studies of nematode specimens from the digestive tract of some rarely collected anguilliform and perciform fishes off New Caledonia, three new species of Cucullanus Müller, 1777 (Cucullanidae) are described: C. austropacificus n. sp. from the longfin African conger Conger cinereus (Congridae), C. gymnothoracis n. sp. from the lipspot moray Gymnothorax chilospilus (Muraenidae), and C. incognitus n. sp. from the seabream Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. is characterized by the presence of cervical alae, ventral sucker, alate spicules 1.30–1.65 mm long, conspicuous outgrowths of the anterior and posterior cloacal lips and by elongate-oval eggs measuring 89–108 × 48–57 μm; C. gymnothoracis n. sp. is similar to the foregoing species, but differs from it in the absence of cervical alae and the posterior cloacal outgrowth, in the shape and size of the anterior cloacal outgrowth and somewhat shorter spicules 1.12 mm long; C. incognitus n. sp. (based on female morphology) differs from other congeneric species parasitic in the Sparidae mainly in possessing cervical alae, the postequatorial vulva, phasmids situated at the mid-length of the tail and in the size of the eggs (75–84 × 45–66 μm). A key to species of Cucullanus parasitizing anguilliform fishes is provided.

Background. The aim of this work was to study the growth of juvenile dentex fed on cooking-extruded diets, determine the level of substitution of fishmeal by soybean meal may be without affecting the growth in this species and its digestibility. Materials and methods. The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (41 g on average) dentex by feeding diets containing 0%–60% soybean meal, for 97 days. Results. Survival at the end of the experiment was high (80%) except for the fish fed diets with 50% and 60% substitution. Growth, feed gain ratio, and protein efficiency ratio (PER) were slightly reduced at higher soybean meal levels. Fish fed diets containing 0% to 40% of soybean meal grew significantly more and FCR was lower than fish fed other diets. No differences were obtained for protein digestibility coefficients of experimental diets (20%, 30%, 40%, and 50% SBM). Conclusion. The results confirm the best protein level for optimum growth seems to be around 50% and 12% lipid level, and maximum soybean meal substitution of 40%.

Three methods of age estimation were compared for Dentex dentex. Based on sectioned otoliths, scales appeared to be relevant only up to 5 years and whole otoliths up to 12 years. The maximum estimated age was 36 years, which constitutes to date the oldest age reported. [ABSTRACT FROM AUTHOR]

The article offers information on the fish occurrence of fish genus Dentex and the species Dentex canariensis Steindachner that is found in the Mediterranean Sea. Topics discussed include the total measurements of the fish that is its length and weight, the interaction of Dentex genus with its Dentex species, and the impact of climate change on these fish.

The present study was aimed to evaluate the capacity of common dentex ( Dentex dentex ) to efficiently use dietary carbohydrates. So, the effects of different type and levels of carbohydrates on growth performance, feed utilization, fish composition, plasma metabolites and key metabolic pathways in liver and white muscle of common dentex are presented. Nine isonitrogenous (43%) and isoenergetic (22 MJ kg − 1 ) diets were formulated combining three types, pregelatinized starch (PS), dextrin (Dx) and maltodextrin (Mx), and three levels (12, 18 and 24%) of carbohydrates. Growth performance was not significantly influenced by treatments. The best feed utilization was observed in 18% Mx group. Higher hepatic lipid content was found in fish fed lower dietary carbohydrate levels. PS induced higher liver and white muscle hexokinase and pyruvate kinase activities compared to the lower values observed for Mx. Malic enzyme and glucose 6-phosphate dehydrogenase in liver and white muscle were lower in Mx group. The influence of dietary carbohydrates source was more noticeable than those induced by the carbohydrate level, when glycolysis and lipogenesis pathways were considered. Common dentex is able to use properly dietary carbohydrates, although optimal dietary inclusion levels are below 24%. The greater protein-sparing effect was promoted by the less complex carbohydrate (maltodextrin) and the best feed utilization indices were obtained at intermediate levels of inclusion (18%). [ABSTRACT FROM AUTHOR]

The common dentex, Dentex dentex (L.), is an iconic marine coastal fish in the Mediterranean Sea. This study was performed in the Bonifacio Strait Natural Reserve (BSNR), (NW Mediterranean Sea). The aims were to: (1) evaluate temporal variation of the artisanal fishing of common dentex (2000-2012); (2) compare and quantify catch rates, fishing techniques and catch composition for artisanal and recreational fisheries, and determine the influence of management measures by both activities; and (3) estimate the production of both artisanal and recreational fisheries. Fishery data were collected from different artisanal fishing surveys (onboard fishing vessels and landings) and recreational fishing surveys (roving). The gears with the highest rates of exploitation were longline (3554 g per 100 hooks) and Trolling (351 g boat−1 h−1 ±SE), respectively, for artisanal and recreational fishing. This study showed that catches by both activities were quantitatively higher in partially protected areas than outside them. Production estimations suggest that the recreational fishery contributes significantly to fishing mortality and that it can magnify the negative effects of artisanal fisheries. Specific measures are needed for the sustainable fishery management of common dentex. [ABSTRACT FROM AUTHOR]

Background. The bogue, Boops boops (Linnaeus, 1758); large-eye dentex, Dentex macrophthalmus (Bloch, 1791); common two-banded seabream, Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817); and axillary seabream, Pagellus acarne (Risso, 1827) are four commercially important sparid species which are distributed in the Mediterranean. Although they are very common in the Mediterranean, information regarding; growth, length at first maturity, and age are scarce and variable. This study provides some of the first data on the above-mentioned biological parameters of these four sparid species for the Turkish coasts of the Aegean Sea (Mediterranean). The aim of the present study is to expand our knowledge on the biology of these commercial sparid species from the Aegean Sea. Materials and Methods. Fish samples were collected between July 2004 and June 2007 by R/V Egesüf from İzmir Bay. Demersal trawl samplings were carried out by a traditional trawl net with a 5 m codend (600 mesh circumference at the codend) and made of knotted polyethylene material with 40 mm mesh size netting. Results. The length–weight relations determined in the course of this study were: W = 0.005L3.25 (bogue), W = 0.005L3.03 (large-eye dentex), W = 0.007L3.31 (common two-banded seabream), and W = 0.009L3.14 (axillary seabream). The respective L¥ and k parameters of von Bertalanffy growth equation were: 29.58 and 0.266 for bogue; 24.3 and 0.399 for large-eye dentex; 28.0 and 0.253 for common two-banded seabream; and 22.7 and 0.315 for axillary seabream. Furthermore, lengths at first maturity were determined as: 12.96 (♀) and 9.35 (♂) cm for bogue; 10.83 (♀) and 11.77 (♂) cm for large-eye dentex; 12.87 (♀) and 13.37 (♂) cm for common two-banded seabream; and 14.45 (♀) and 13.91 (♂) cm for axillary seabream. Conclusion. The presently determined parameters of age, growth, reproduction, and mortality of these four species will be useful for estimating the relevant parameters of population dynamics and will hopefully contribute to a better understanding of the long-term changes of the stock sizes. [ABSTRACT FROM AUTHOR]

Background. The Morocco dentex, Dentex maroccanus Valenciennes, 1830, is a sparid species, which has economical value and its population is expanding in a 20-500 m depth range throughout the Mediterranean. Worldwide, there is a lack of information about the biology (age, growth, reproductive season, first maturity length) of this species. This study provides the first data on population parameters of D. maroccanus in the Aegean Sea. Materials and methods. Dentex maroccanus were caught in the Saros Bay (north Aegean Sea) between September 2006 and September 2008. The length-weight relations were determined according to the allometric equation: W = aLb. The spawning season was determined by analyzing the maturity stages and gonadosomatic index, while first maturity length was defined as the size at which 50% of individuals were mature. Growth parameters were estimated using the von Bertalanffy growth equation. Results. The female-male ratio was 4.8 : 1. The total length (weight) of females ranged from 11.4 cm to 25.2 cm (26.2 g to 289.3 g) and of males from 12.8 cm to 24.3 cm (19.8 g to 223.9 g). The growth parameters were calculated as L∞ = 25.31 cm, K = 0.49 year-1, t0 = -0.30 year. The length at first maturity for females and males was 13.0 cm and 15.8 cm, respectively. Monthly values of the gonadosomatic index indicated that spawning occurred mainly between June and September. Conclusion. Results reported in this work will contribute to the knowledge on the biology of D. maroccanus in the north Aegean Sea and also to a better understanding of its role in the marine ecosystem. [ABSTRACT FROM AUTHOR]

The mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming-up hypothesis (i.e., the increase in the production of high-trophic-level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming-up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming-up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low-trophic-level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds. Cambios en el Nivel Trófico de las Especies de Maricultura Mediterránea [ABSTRACT FROM AUTHOR]

In Japan, a Mycobacterium marinum-like mycobacterium was isolated from the yellowtail, Seriola quinqueradiata. The species was identified as M. marinum by a commercial mycobacterial DNA-DNA hybridization kit. Nevertheless, PCR restriction analysis of the DNA of its RNA polymerase β-subunit gene definitively showed that this Mycobacterium sp. was M. ulcerans. PCR analysis revealed the genotypic characteristics of M. ulcerans in the Mycobacterium sp., only the mup053 gene sequence being absent, as has been found previously in other piscine mycobacteria such as M. marinum strains DL240490 and DL045 and M. pseudoshottsii. With one exception, this Mycobacterium sp. and M. pseudoshottsii had identical 16S rRNA gene sequences, which is also probably true of M. marinum strains DL240490 and DL045. Similarly, according to comparisons of the 16S rRNA gene, ITS region, and hsp65 gene sequences, this Mycobacterium sp. is more closely related to M. pseudoshottsii than to M. ulcerans or M. marinum. A PCR product of approximately 2000 bp was amplified from region of difference 9 in the Mycobacterium sp. The nucleotide sequence revealed insertion of IS 2404, the sequence of which is 1366 bp long. The novel single nucleotide polymorphisms identified in this region distinguished this Mycobacterium sp. from M. marinum strain DL240490 and M. pseudoshottsii. The present findings raise the possibility that these species have a common ancestor. Further studies are required to improve our understanding of the relationship between their geographical origin and genetic diversity. [ABSTRACT FROM AUTHOR]

The particular metabolic strategies of the common dentex ( Dentex dentex) to face a period of prolonged starvation and subsequent refeeding were assessed. Plasma metabolites, endogenous reserves, and the activity of key enzymes of intermediary metabolism in liver, white muscle, and heart were evaluated. Plasma glucose, total lipid, triglycerides, total-, HDL- and LDL-cholesterol, and protein levels, liver, and white muscle glycogen, and perivisceral, and muscle fat were significantly reduced by starvation, whereas liver lipid content was surprisingly increased. Those enzymes involved in phosphorylation and oxidation of glucose and lipid synthesis, as well as alanine aminotransferase activity, were significantly depressed in liver of starved fish. The increase in β-hydroxyacyl-CoA dehydrogenase (HOAD) indicated an enhanced fatty acid oxidation during starvation. Part of the acetyl-CoA generated by β-oxidation was oxidized in the hepatic Krebs cycle, as reflected the increased citrate synthase (CS) activity. The oxaloacetate required for the reaction catalized by CS activity would be supplied by aspartate aminotransferase (ASAT) activity whose activity was also enhanced. Glutamate dehydrogenase also increased to deaminate the glutamate produced by transaminases, especially by the increased ASAT activity. Liver gluconeogenesis of starved fish was maintained at the same rate that in controls, with glycerol playing an important role as glucogenic substrate. The increased hepatic β-hydroxybutyrate dehydrogenase (β-OHBDH) activity indicates that part of the acetyl-CoA arriving from β-oxidation was being diverted for ketone bodies production with dentex liver playing an important role in providing ketone bodies as fuels for other tissues under such circumstances. Most enzyme activities in white muscle of starved dentex were significantly depressed. In heart, starvation induced an important inhibition of those enzymes involved in glucose and protein metabolism, whereas CS, HOAD, and β-OHBDH activities were maintained at control levels. Although several biomarkers assayed returned to control values after refeeding, many others did not, which indicate that after 3 weeks of refeeding, pre-starved dentex is still experiencing a transient period of metabolic adjustments directed toward the restoration of body mass. [ABSTRACT FROM AUTHOR]

Abstract: The ultrastructural organization of the female reproductive system of Metadena depressa, digenean intestinal parasite of Sparidae (Dentex dentex), was investigated by electron microscopy. The vitellogenesis is divided into four stages: stage I, vitellocytes have a cytoplasm mainly filled with ribosomes and few mitochondria; stage II, beginning of the synthetic activity; stage III, active shell globule clusters synthesis; stage IV, mature vitellocytes are filled with shell globule clusters and generally contain several large lipid droplets. Glycogen granules are grouped at the periphery of the cell. The three stages of the oogenesis process take place in the ovary: stage I, oogonia are undifferentiated small cells located at the periphery of the organ; stage II, primary oocytes possess a higher nucleo-cytoplasmic ratio and a nucleus with a nucleolus and synaptonemal complexes indicating the zygotene-pachytene stage of the first meiotic division; stage III, mature oocytes are located in the proximal region of the organ and possess a cytoplasmic chromatoid body and cortical granules in a monolayer close to the periphery of the cell. [Copyright &y& Elsevier]

Vitellogenesis of Aphallus tubarium, an intestinal parasite of Sparidae (Dentex dentex), was studied by transmission electron microscopy. The ultrastructural features allowed us to distinguish 4 stages in the vitellogenesis process. In stage I, vitellocytes have a cytoplasm mainly filled with ribosomes, but few mitochondria. In stage 2, there is an increase in amount of endoplasmic reticulum and few Golgi complexes. There is production of shell globules that coalesce into clusters in stage 3; some glycogen particles are observed via the Thiery method. Finally, in stage 4, mature vitellocytes are filled with shell globule clusters and generally contain a large lipid droplet. Glycogen particles are grouped at the periphery of the cell. [ABSTRACT FROM AUTHOR]

Barnard's dentex Dentex barnardi is a relatively slow-growing, late-maturing species with an intermediate longevity (maximum recorded age = 13 years). The length and age structures of the population were similar for males and females; however, the sex ratio was female biased at 1:1.6. Growth was described by the three-parameter von Bertalanffy model as Lt = 332.14(1 - e–0.14(t + 3.97)). The species is a rudimentary hermaphrodite and the length- and age-at-50% maturity was calculated as 220 mm fork length and 3.7 years respectively. Reproductive activity in fish sampled in southern Angola was observed over an extended period during the austral summer (August–February) and a drop in water temperature is a possible ultimate cue for spawning activity in this species. The diet consisted mainly of teleost fish and mysid shrimps. The life-history characteristics of the species render it susceptible even to low levels of fishing pressure. Owing to the paucity of information on the fisheries for D. barnardi, and the current fisheries management situation in Angola, conventional management tools are not considered appropriate. The establishment of marine protected areas is suggested as the most appropriate management strategy for the species. [ABSTRACT FROM AUTHOR]

The present study was carried out to compare the tissue composition of wild and farmed common dentex (Dentex dentex) and the major nutrients in order to further explore the dietary requirements of this species. Wild (41±14 g) and farmed (10±2 g) fish were analyzed for proximate composition, fatty acid profile and vitamin C and E muscle and liver content. The fat content of the farmed population was almost six times higher than that measured in wild fish at the expense of water content. There were no significant differences in the protein and ash content between the two populations. The vitamin C content was insignificantly lower in wild fish liver while differences were significant in muscle compared to their farmed conspecifics. Vitamin E concentration was found to be significantly higher in both examined tissues of the farmed fish. The fatty acid profiles were different between the wild and farmed individuals. Wild fish livers were significantly richer in ω-6 fatty acids, poorer in total monounsaturates (MUFA), but no differences were observed for total polyunsaturates (PUFA) and saturated fatty acids (SFA). As regards muscle tissues, farmed fish were found to contain higher 22:6ω3 levels but significantly lower 16:1ω7 and 18:1ω9 levels than the wild ones. The information given by the present study should be evaluated for the further improvement of common dentex diets. [ABSTRACT FROM AUTHOR]

Although the fatty acid (FA) requirements of marine teleosts not only are a function of the amount of each FA individually, but also of the relative proportions of the FAs; mostly, the interactions have been ignored and merely limited to a few interrelations of 20:4[ n-6], 20:5[ n-3], and 22:6[ n-3]. To address this shortcoming, viable eggs of Dentex dentex were obtained from broodfish in captivity. Nine viability parameters (VP) (i.e., floating rate (FR), hatching rate (HR), and survival rate (SR) from day 0 to 5 posthatch (dph)) that are currently used in mariculture systems were determined. Egg FAs were characterized and quantified. One hundred and twenty ratios were made based on the FA contents estimated. Sixty-four ratios were significantly and strongly correlated to embryo/larva success through 201 simple regression models ( r2 = 0.640-0.948; P = 0.006- P<0.001). Of the 201 significant relationships found, ∼12, ∼5, ∼2, ∼3, ∼22, ∼23, ∼21, and ∼13% show the relations of the egg FA ratios with FR, HR, and SR at 0, 1, 2, 3, 4, and 5 dph, respectively. All the FAs characterized in this study were significantly correlated to VPs through either their individual relative proportions or relative proportion of their combinations. This study, for the first time, presents a series of new FA interrelations and uncovers their biological meanings under both basic and applied aspects through correlating them to embryo/larva success. J. Exp. Zool. 317:55-72, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Since the timing of the lipovitellin heavy chain (LvH) of vitellogenin Ab (VtgAb) degradation during marine teleosts ontogeny is poorly understood, the current study was planned to address some aspects of this shortcoming. Fertilized eggs (before epiboly) of Dentex dentex were analysed. Vtg-derived proteins, that appeared as 6 protein bands after SDS-PAGE, were purified using specific ion exchange chromatography. Five bands (i.e., ∼78, ∼57, ∼22, ∼19, and ∼17 kDa) were merely stained with Coomassie Blue and one band (i.e., ∼16 kDa) only with Periodic Acid Schiff (PAS). The ∼16 kDa protein band was subjected to a mass spectrometry-based sequencing. These results showed that the ∼16 kDa protein band contains a mixture of “LvH-Ab” derivatives with the same molecular weight. The specific staining system (i.e., PAS) also revealed the glycosylation of some of the LvH-Ab fragments inside the ∼16 kDa protein band. The study provides new data about fragmentation of the LvH-Ab in marine pelagophil teleosts. [Copyright &y& Elsevier]

The article discusses a research study on the parasite from the fishes Dentex canariensis and D. gibbosus in the Mediterranean Sea and Atlantic Ocean known as Lamellodiscus euzeti N. of the species Monogenea: Diplectanidae. Collected were 27 specimens of Dentex canariensis and 48 Dentex gibbosus fishes from Ouakam and Soumbedioune fish markets in Senegal and four Dentex gibbosus from the Tunisian Sfax fish market then dissected, frozen and examined. Results showed 70% prevalence of D. canariensis from off Senegal in 19 infected out of the 27 fish examined, 67% prevalence of D. gibbosus from off Senegal in 32 infected out of the 48 fish tested and 100% prevalence of D. gibbosus from off Tunisia on the four infected fish examined.

Dentex (mean initial weight 324 ± 5 g) from a fish farm were divided into two groups (control and fasted). At the end of experimental period (5 wk), dentex were sampled for gross muscle composition and quality analysis. For post mortem muscle analysis, after death, fish were kept in a cold chamber at 4 C, and muscle samples were taken at 4 (prerigor state), 24 (rigor state), and 82 (postrigor state) h after slaughtering. In each fish, textural and biochemical parameters were determined. During starvation, there was a drastic reduction in muscle lipid content and a relative increase of the proteolysis. There were little qualitative changes in the fatty-acid profile of muscle lipids, although a significant increase in n3/ n6 ratio in the starved dentex was detected. Starved fish also showed higher muscle firmness, but no differences in pH and water holding capacity were observed. Total and myofibrillar protein and collagen content increased significantly in starved dentex. Firmness during post mortem storage was significantly higher in starved fish, compared with control group. Preslaughtering feeding status showed decisive influence on the evolution dentex muscle quality parameters during cold storage. [ABSTRACT FROM AUTHOR]

Abstract: Free amino acids (FAAs) play a key role in the physiology of marine teleosts (eggs, embryos, and larvae). However, the relationship between the egg FAAs content and the production of viable embryos and larvae (at different developmental stages) in batch spawner pelagophils has not yet comprehensively been investigated. Viable eggs of common dentex, Dentex dentex, were obtained from captive broodstocks. Egg wet weight (WW), dry weight (DW), and water content (%W) and viability parameters, or VPs (egg floating rate [FR], hatching rate [HR], and larval survival rate [SR] at days 0 to 5 posthatch) were determined for 45 egg batches. The egg batches were classified according to their HR magnitude. Twelve egg batches with the same WW, DW, and %W were taken from the same broodstock and at the same developmental stage to determine the qualitative and quantitative composition of FAAs. The total FAA (TFAA) content, glutamic acid (Glu), asparagine (Asn), glutamine (Gln), and arginine (Arg) were correlated with VPs. The Glu was significantly correlated with HR and SR at 0 day posthatch (dph), the Asn with SR at 1 dph, and the Gln and Arg with FR and HR. Of the 361 ratios made based on the absolute concentrations of FAAs, 24 ratios were correlated with VPs (P < 0.005) through 42 simple regression models (R2 =0.641 to 0.846). Of the 42 significant relationships found ∼10%, ∼28%, ∼12%, ∼30%, ∼8%, ∼4%, ∼2%, ∼2%, and ∼2% of the models show the relations of the egg FAAs ratios with FR, HR, SR at days 1 to 5 posthatch, and %W, respectively. A path coefficient in combination with a Pearson''s correlation coefficient provided a series of statistical evidences to show the effects of the egg FAAs interrelations on the relationships found between quantitative composition of a FAA and a VP. [Copyright &y& Elsevier]

Determining an adequate macronutrient balance is essential to guarantee the production success. As protein is the limiting component for fish food, the utilization of lipids or carbohydrates as partial substitutes of this nutrient is a challenge to improve its use. In order to get an approximation of the maximum levels of utilization for carbohydrates and/or lipids and determine the most adequate macronutrient to partly replace protein as the main energy source of diets for dentex (91.7 ± 1.4 g mean weight), four experimental diets with different protein:lipid:carbohydrate percentages (43/16/28, 43/24/4, 38/19/28 and 38/24/13) were tested for 13 weeks. The results indicated the possibility of using 38% of dietary protein without affecting growth performance, under the experimental conditions. There were no differences among the four diets either in most of the nutritive utilization indicators or in the body composition and haematological parameters. The influence of dietary composition was only observed in the feed intake, being higher with more dietary carbohydrates, and the hepatosomatic index and protein efficiency ratio, showing more elevated values in diets with a higher lipid level. The dentex capacity of using both carbohydrates and lipids efficiently to obtain the necessary energy for its correct growth, as well as to compensate the energetic ‘vacuum’ caused by the dietary protein reduction, under the assayed conditions, was confirmed. [ABSTRACT FROM AUTHOR]

The article presents a study on the importance of dentex eggs lipid classes (LCs) and fatty acids (FAs) with regards to common dentex embryonic and larval development in marine pelagophil teleosts. The study focuses on larva parameters using egg buoyancy, floating rate (FR), hatching rate (HR) and survival rate (SR). It presents the methods, formulated models and the implication of sphingomyelin, phosphatidylcholine, phosphatidylserine with phosphatidylinositol to FR and SR results. It features the predicted egg quality as well as the research evaluation.

Abstract: A wide range of antioxidant mechanisms are present in fish maintaining an adequate “oxidative balance”. When this balance tilts in favor of the oxidant agents “oxidative stress” arises with detrimental effects in molecules of great biological importance. Little has been reported about the influence of different dietary energy sources on antioxidant defenses in fish. The influence of different dietary macronutrient combinations on the key antioxidant enzyme activity, the oxidative damage to lipids and proteins and the possible modifications in the SOD isoenzymatic pattern were evaluated in liver, white muscle, heart and erythrocytes of common dentex (Dentex dentex). Four experimental diets with different protein:lipid:carbohydrate ratios (43/16/28; 43/24/4; 38/19/28 and 38/24/13) were formulated. In general, neither different dietary macronutrient levels nor the interaction among them induces substantial modifications in enzymatic antioxidant defense mechanisms. Two constitutive SOD isoforms, CuZn-SOD I and Mn-SOD, were detected in the tissues analyzed in all experimental groups, independently of diet formulation, but, a third SOD isoenzyme, CuZn-SOD II seems to be induced in white muscle by higher dietary protein levels. Densitometric analyses of western blotting membranes revealed higher CuZn-SOD expression in the heart of dentex fed on lower dietary protein levels, although these differences did not correlate with the SOD activity. Finally, a direct relation exists between the lipid or protein intake level and occurrence of oxidative damage in different tissue components. [Copyright &y& Elsevier]

The article presents a parasitological study regarding the identification of the composition of parasites in Dentex dentex, also known as common dentex, under the farming systems in Turkey. It says that aquaculture activities in Turkey started in the 1970s with fish farming in which several parasites have been reported in various species of fishes. An examination of seven D. dentex for ectoparasites and endoparasites in July to August 2008 is made in which their gill arches and intestines were tested with the use of a dissecting microscope. The results show the presence of a female Caligus mauritanicus in the gill filaments. The said parasite found has 20% prevalence and 5.6 mean intensity having a measurement of four to seven millimeters.

Abstract: Digestive physiology of on-growing common dentex (Dentex dentex), including protease, amylase and lipase activity in stomach, pyloric caeca, anterior and posterior intestine, was evaluated. The influence of dietary macronutrient balance on these digestive processes was also assessed. Four experimental diets with different protein:lipid:carbohydrate ratios (43/16/28; 43/24/4; 38/19/28 and 38/24/13) were formulated. The highest activity for acid proteases was located in the stomach at pH 1.5. Alkaline proteolytic activities showed the highest values in the pyloric caeca and posterior intestine at pH 8.5–9.0. Dentex showed substantial amylase activity in the pyloric caeca and posterior intestine. Lipase activity was higher in the pyloric caeca, anterior and posterior intestine and was not detected in the stomach. Feed composition influenced alkaline protease activity in the anterior and posterior intestine and was higher for the diet with less protein and more carbohydrates. Enhanced amylase activity was observed in the pyloric caeca and posterior intestine in those groups fed on higher carbohydrate and lower lipid level diets. High dietary carbohydrate levels produced the highest lipase activity but this only occurred in the anterior intestine. We can conclude that the digestive tract of dentex adapts well to protein digestion and possesses a high potential for digesting the other dietary macronutrients, too. Dietary carbohydrate content seems to induce changes in protease, amylase and lipase activity. [Copyright &y& Elsevier]

The article assesses the significance of the quantitative composition of egg yolk proteins derived from vitellogenin (Vtg) and their effects on dentex embryo and larvae viability. Study shows that all the egg yolk proteins were correlated to the viability parameters (VPs) with 0.634 maximum effect. This indicates the relevance of the egg's yolk protein content for early larval development and embryogenesis. This also reveals the potential use of protein in predicting the quality of egg in teleosts.

Background. The aim of this work was to study the growth of juvenile dentex fed on cooking-extruded diets, determine the level of substitution of fishmeal by soybean meal may be without affecting the growth in this species and its digestibility. Materials and Methods. The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (41 g on average) dentex by feeding diets containing 0%-60% soybean meal, for 97 days. Results. Survival at the end of the experiment was high (80%) except for the fish fed diets with 50% and 60% substitution. Growth, feed gain ratio, and protein efficiency ratio (PER) were slightly reduced at higher soybean meal levels. Fish fed diets containing 0% to 40% of soybean meal grew significantly more and FCR was lower than fish fed other diets. No differences were obtained for protein digestibility coefficients of experimental diets (20%, 30%, 40%, and 50% SBM). Conclusion. The results confirm the best protein level for optimum growth seems to be around 50% and 12% lipid level, and maximum soybean meal substitution of 40%. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to assess the potential effects of replacing part of the dietary protein by lipid or carbohydrate on the characteristics of dentex muscle. Dentex were hand-feed four isoenergetic diets (22.6 MJ kg−1 gross energy) with protein:lipid:carbohydrate ratios 43/16/28 (D1); 43/24/4 (D2); 38/19/28 (D3), and 38/24/13 (D4). At the end of the feeding period, biometric parameters, textural properties of muscle, as well as protein, lipid and collagen contents, and electrophoretic protein profiles of this tissue were studied. The decrease in dietary protein content improved textural parameters (increased firmness and water holding capacity). Within each dietary protein level, diets with high carbohydrate and low lipid contents resulted in lower values of muscle firmness than diets with low carbohydrate and high lipid contents. This increase in firmness matched with a lower muscle lipid and higher muscle collagen contents. SDS-PAGE separation of muscle extracts showed a higher relative contribution of myosin to total optical density in muscle from those animals fed lower dietary protein, although no significant difference in fish texture could be attributable to this finding. Results indicate a favourable effect of replacing protein by alternative energy sources (lipids or carbohydrates) on the rheological properties of muscle in this species, this improvement was more noticeable when protein was replaced by lipid than by carbohydrate. [Copyright &y& Elsevier]

Abstract: The influence of the dietary macronutrient balance on the intermediary metabolism of common dentex (Dentex dentex L.) was evaluated. Four experimental diets combining high and low levels of macronutrients were formulated. Dentex fed on 43% protein had higher liver and muscle lipid content, corresponding with an increased hepatic G6PDH activity. This “excess” of hepatic lipids at higher protein levels could be used to obtain energy as would be reflected by hepatic HOAD. In the liver, 43% of dietary protein induced higher AlaAT and FBPase activities. Similarly, dentex fed on the P43C28 and P38C28 diets showed an increased hepatic and muscular gluconeogenic pathways (higher FBPase activity) from amino acids (elevated AlaAT) and/or glycerol (elevated GK). However, changes in glycemia were not observed among dietary treatments. At coronary level, the use of lower dietary protein induced an increase in the activity of glycolytic (PK and HK-IV) and lipolytic (HOAD) enzymes. Considering the overall results and the experimental conditions, it could be suggested that dietary protein could be reduced until 38% without affecting negatively the normal physiology of dentex. Moreover, high dietary carbohydrate levels could not be used efficiently by dentex given that gluconeogenesis occurs. [Copyright &y& Elsevier]

Larvae of two Mediterranean Sparidae species, Sparus aurata and Dentex dentex, were used to test the efficacy of a peroxide-based product (Ox-Aquaculture©) on the reduction in bacterial load in larval rearing water and its effects on larval survival. Eleven-day-old S. aurata larvae and 15-day-old D. dentex larvae were exposed to different concentrations of Ox-Aquaculture© (50, 100 and 200 mg L−1, and 20 and 50 mg L−1 respectively) for 1 h. Results indicated that 50 and 20 mg L−1 were the most effective concentrations for the reduction in bacterial load (at least one order of magnitude) after 1 h treatment, without affecting larval survival and/or vitality in 11 dph S. aurata and 15 dph D. dentex larvae respectively. Ox-Aquaculture© concentrations of 200 and 50 mg L−1 during 1 h affected negatively final survival rate of the larvae of S. aurata and D. dentex respectively. [ABSTRACT FROM AUTHOR]

Abstract: The digestive physiology of common dentex was studied by assessing the activity of different pancreatic (trypsin, chymotrypsin, amylase and lipase), intestinal (alkaline phosphatase, aminopeptidase N, maltase and leuncine–alanine peptidase) and gastric (pepsin) enzymes from hatching until the juvenile stage (50 dph at 19 °C). Enzymes involved in the digestion of protein, lipid and carbohydrate were present in common dentex larvae at hatching and before the onset of exogenous feeding. The specific activity of trypsin and chymotrypsin in newly hatched larvae was higher than that of amylase and lipase, indicating the importance of these enzymes in the cleavage of yolk proteins and hatching, while after hatching, the activity of these serine proteases dramatically decreased, whereas lipase showed the opposite trend. A progressive shift in activity from alkaline to acid proteases was observed during larval development, reflecting that alkaline proteases were not longer the main digestive enzymes involved in protein digestion after the development of gastric glands and onset of acidic digestion. Lipase total activity in common dentex peaked at 35 dph and decreased after weaning. Diet change due to weaning might partially explain the decrease in lipase activity, although this change might be also indicative of a change in the nutritional requirements of this species, since the juveniles prefer diets with high protein levels than those with lower protein and higher lipid content. Regarding intestinal enzymes, leucine–alanine peptidase and alkaline phosphatase and aminopeptidase N were found in newly hatched larvae, while maltase was detected after the onset of exogenous feeding. The achievement of an efficient brush border membrane digestion takes place much earlier (6–12 dph) than in any of the studied species which might reflect the different metabolic profile and rapid growth of this species. [Copyright &y& Elsevier]

The aim of the present study was to set up reference intervals for biochemical parameters in new candidate species of Mediterranean marine fish culture—striped sea bream, Lithognathus mormyrus and common dentex, Dentex dentex as well as traditionally cultured species—gilthead sea bream, Sparus aurata. The reference biochemical values were assessed for plasma cortisol, glucose, Ca, inorganic P, Na, K, Cl, C-reactive protein, hematocrit, and prothrombin time. The biochemical reference values established may allow important physiological decision in adaptation process of striped sea bream and common dentex as well as provide contribution to our present knowledge on gilthead sea bream physiology. [ABSTRACT FROM AUTHOR]