Seabream Pagrus Auriga Research Articles

Toxicity of Photobacterium damselae subsp. damselae strains isolated from new cultured marine fish

The in vivo and in vitro toxicity of bacterial cells and their extracellular products (ECPs) from 16 strains of Photobacterium damselae subsp. damselae isolated from 7 epizootic outbreaks were evaluated. On the basis of their 50% lethal dose (LD50) values (about 1 x 10(50 CFU), these strains may be considered as moderately virulent. However, their ECPs were strongly lethal for redbanded seabream Pagrus auriga causing fish death within 2 h post-inoculation (protein concentration ranged between 2.1 and 6.41 microg g(-1) fish). The bacterial ECPs tested exhibited several enzymatic activities, such as amylase, lipase, phospholipase, alkaline phosphatase, esterase-lipase, acid phosphatase, and beta-glucosaminidase. These ECPs displayed a strong cytotoxic effect on 4 fish and 2 mammalian cell lines, although this activity disappeared when ECPs were heated at 100 degrees C. The virulence of the strains tested could not be related to the hemolytic activity or to the production of the toxin damselysin. Therefore, another unknown type of toxin could play an important role in the virulence mechanisms of this bacterial pathogen.

Larval ontogeny of redbanded seabream Pagrus auriga Valenciennes, 1843 with special reference to the digestive system. A histological and histochemical approach

The larval ontogeny of redbanded seabream Pagrus auriga was studied histologically and histochemically from 0 until 30 days after hatching (DAH). According to the source of food and the structural changes in the digestive tract, larval development was divided into four stages: (1) lecitotrophic (0–2 DAH), (2) lecitoexotrophic (3–4 DAH), (3) exotrophic I (5–15 DAH), and (4) exotrophic II (16–30 DAH). During the first three stages, larvae underwent an intense organogenesis, this being particularly intense from stage 2 (mouth and anus opening) to early stage 4 (appearance of gastric glands). Subsequent development during stage 4 was characterized by the proliferation and growth of pre-existing structures. During stage 1, the mouth and the anus were closed and the digestive tract undifferentiated (straight tubular segment), as well as the majority of the organs (observed as undifferentiated cells groups or primordial structures). As resorption of endogenous reserves proceeded (3–4 DAH) larvae acquired initial absorptive and digestive equipments necessary for first feeding (enterocytes brush border, zymogen pancreatic granules, and ducts connecting accessory glands to the gut). During stage 2, the digestive tract started to differentiate and buccopharyngeal cavity, oesophagus, incipient stomach, and anterior, mid and posterior intestine were distinguished. During stages 2 and 3, prey capture became guaranteed (early development of jaw, fins, teeth, and taste buds) and the digestive and absorptive processes continued developing (appearance of the gut mucosa folds and protein supranuclear inclusions and lipid infranuclear vesicles in enterocytes). The endocrine elements (Langerhans islets and thyroid follicles) except corpuscles of Stannius appeared from 3 to 5 DAH (mouth opening and total yolk resorption). During stage 2 and early stage 3 (3–7 DAH), the circulatory and excretory systems became functional, with the compartmentalization of the heart and the development of renal corpuscles, tubules, and collecting ducts. The beginning of stage 4 was marked by the appearance of gastric glands (16 DAH), which subsequently proliferated in association with the increase in size of the accessory glands. Such event ensured the development of gastric digestion, which around 30 DAH became fully guaranteed (transition from larval to juvenile stage). During stage 4, gill filaments and lamellae proliferated, the heart completed its compartmentalization, the pronephric and mesonephric regions in the kidney developed, and endocrine elements proliferated. The structural information presented here constitutes an initial step towards the determination of the functional systemic capabilities of P. auriga larvae, and thus the physiological requirements needed for optimal welfare and growth.

Life history of the red-banded seabream Pagrus auriga (Sparidae) from the coasts of the Canarian archipelago

Summary Red-banded seabream Pagrus auriga (N = 615) were caught off the Canary Islands from January 2003 to December 2004. Total length ranged from 120 to 780 mm. The species was characterized by protogynous hermaphroditism. The male :female ratio was in favour of females (1 : 8.2). The reproductive season extended from September to February, with a peak in spawning activity in October–November. Fifty percentage maturity was reached at 387 mm total length by females and 533 mm by males. The length–weight relationship for all individuals was described by the parameters: a = 0.0086 and b = 3.014, when length is given in mm and weight in grams. Otolith age readings indicated that the population consists of 19 age groups, including a very high proportion of individuals between 0 and 7 years old. Growth analysis reveals that the species is slow-growing and relatively long lived (18 years). The von Bertalanffy growth parameters for the entire population were: L∞ = 803 mm, k = 0.081 year−1 and t0 = −2.17 year. Growth differed between males and females. The instantaneous rate of natural mortality for all fish was: M = 0.164 year−1.

Characterization of microsatellite loci for the redbanded seabream, Pagrus auriga (Teleostei, Sparidae)

AbstractThe redbanded seabream Pagrus auriga (Teleostei, Sparidae) is a species of a high commercial value in Spain. There is currently little information available about the genetic characteristics of both wild and cultured populations. In this survey, we have developed eight polymorphic microsatellites for the redbanded seabream using an enriched genome library protocol. All of them were polymorphic in the 64 individuals tested, 22 of which were wild specimens, and 42 were individuals from a captive reproductive broodstock. These markers can potentially be useful tools for use in population genetic studies.

Phylogenetic Relationships of the Sparidae Family (Pisces, Perciformes) Inferred from Satellite-DNA

The phylogenetic relationships within the taxonomically controversial Sparidae family of fish are inferred using two satellite-DNA families as phylogenetic markers. The cross-hybridization, strength and restriction patterns of hybridizing the monomer units of these two satellite-DNA families to the DNAs of ten sparid species, served as an index of taxonomic divergence. The results indicate the existence of two separate lineages from a common ancestor, each one clearly defined by either satellite-DNA family. The results also indicate a closeness between Sparus and Diplodus, and a divergence between Spams and Pagrus. These data agree with the currently. Accepted opinion considering Sparus a monotypic genus which should include only Sparus aurata, and recommending the separation of the genus Pagrus to include the common seabream Pagrus pagrus and the red-banded seabream Pagrus auriga, among others.