Ballan wrasse, Labrus bergylta (Ascanius, 1767), has commercial interest as a cleaner fish in aquaculture, and culture of juveniles may be a good alternative to catching wild fish. However, basic knowledge of early development is limited. To study hatching and larvae ontogenesis, eggs were collected from a broodstock of wild caught ballan wrasse held in captivity. Larvae were fed rotifers for 27 days; Artemia was introduced at day 20 and fed larvae to day 49 after hatching. Age at hatching, and larval ontogenesis based on external morphological features were linked to the chronological age of larvae as days post hatching (DPH) and physiological age as degree day (°C.day) and standard length (SL). The ballan wrasse egg diameter was 1.05 ± 0.04 mm and 0.87 ± 0.05 mm with and without the gelatinous layer, respectively, and hatched at a SL of 3.64 ± 0.05 mm, 7 days, i.e., 72°C.day, after fertilization. The ontogeny of larvae from hatching to metamorphosis was divided into four stages. Yolk sac larva, 0 to 9 DPH (SL 4.28 ± 0.11 mm), where mouth opens and pigmentation of the eyes is seen. Dilated swim bladder is visible. Preflexion larva, 10 to 25 DPH (SL 5.35 ± 0.30 mm); yolk sac has disappeared, and initial formation of caudal fin rays occurs. Gaseous inflation of swim bladder is observed. Flexion larva, 26 to 33 DPH (SL 5.9 ± 0.78 mm), initial resorption of primordial fin fold is seen. Postflexion larva, 34 to 49 DPH (SL 10.52 ± 0.82 mm) by the end of this stage (age 686°C.day), the dorsal, anal, caudal and pelvic fins were developed. The ontogenetic development, linked to SL, chronological and physiological age, provides a baseline reference and makes it possible to compare developmental levels in future studies of ballan wrasse in culture and wild populations.
The organogenesis of ballan wrasse, Labrus bergylta, Ascanius, 1767 larvae was studied during the first 49 days after hatching (DAH) with histological and histochemical methods. During the yolk sac stage (0-9 DAH), a syncytial layer had surrounded the yolk sac. At mouth opening, we distinguished a primordial liver and swim bladder, a buccopharyngeal cavity with gill arch cartilages, an exocrine and endocrine pancreas, and a primordial gastrointestinal tract. By the end of this stage, the heart had become functional, the swim bladder had dilated, olfactory organs and otoliths had developed, the pituitary gland and thyroid follicle could be distinguished, and the eye had become pigmented. During preflexion (10-25 DAH), the swim bladder had inflated, and the renal corpuscles and tubules had joined the collecting duct towards the urinary bladder. Mucous cells were observed, which may provide secretions that protect against abrasion and pathogens, and the density of these cells increased in the buccopharyngeal cavity and oesophagus. During flexion (26-33 DAH), secondary lamellae had developed. Increasing functionality of the digestive system coincided with a shift to the appearance of AB-positive mucous cells in the gill openings and the digestive tract. In addition, pharyngeal teeth had developed, which suggested that food preferences might change to include hard-bodied prey. Stage 4 was mainly characterized by increases in the size and complexity of pre existing organs and structures. At 49 DAH, metamorphosis was complete. The temporal sequence of development of the various systems may provide baseline information for aqua culturists and fish biologists in future studies on fish health, feed, feed development, and cultivation of ballan wrasse.
Eight primary embryonic developmental stages were assigned to eggs of ballan wrasse Labrus bergylta using key morphological features following standardized nomenclature: Ia, Ib, II, III, IV, V, VI and VI+, reared from single family clutches under comparable environmental conditions in Ireland and Norway. Development in L. bergylta is typical of demersal marine finfish species with a short egg stage. Hatching occurred c. 123 h post-fertilization (hpf) equivalent to 62·5 degree days at 12·2 ± 1·10° C (mean ±S.D.), after which the larvae swam intermittently near the surface of the water column.
The research objective was to study the presence of DNA damages in haddock exposed to petrogenic or pyrogenic polyaromatic hydrocarbons (PAHs) from different sources: 1) extracts of oil produced water (PW), dominated by 2-ring PAHs; 2) distillation fractions of crude oil (representing oil-based drilling mud), dominated by 3-ring PAHs; 3) heavy pyrogenic PAHs, mixture of 4/5/6-ring PAHs. The biological effect of the different PAH sources was studied by feeding juvenile haddock with low doses of PAHs (0.3-0.7 mg PAH/kg fish/ day) for two months, followed by a two-months recovery. In addition to the oral exposure, a group of fish was exposed to 12 single compounds of PAHs (4/5/6-ring) via intraperitoneal injection. The main endpoint was the analysis of hepatic and intestinal DNA adducts. In addition, PAH burden in liver, bile metabolites, gene and protein expression of CYP1A, GST activity, lipid peroxidation, skeletal deformities and histopathology of livers were evaluated. Juvenile haddock responded quickly to both intraperitoneal injection and oral exposure of 4/ 5/6-ring PAHs. High levels of DNA adducts were detected in livers three days after the dose of the single compound exposure. Fish had also high levels of DNA adducts in liver after being fed with extracts dominated by 2-ring PAHs (a PW exposure scenario) and 3-ring PAHs (simulating an oil exposure scenario). Elevated levels of DNA adducts were observed in the liver of all exposed groups after the 2 months of recovery. High levels of DNA adduct were found also in the intestines of individuals exposed to oil or heavy PAHs, but not in the PW or control groups. This suggests that the intestinal barrier is very important for detoxification of orally exposures of PAHs.
Biochemical tests were done in all strains by "Áutomated Microbial Analyzer" (Biolog, US). The metabolic profiles were compared automatically using the Biolog microtiter plates with the MicroLog GN database. Biolog identifications were reported if the similarity index of the genus or species was 0.5 or greater after 24 hr of incubation. Test samples were incubated under the same conditions as used. All tests
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