• Journal of fish pathology
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• v.16 no.2
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• pp.75-80
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• 2003

Red scabream, Pagrus major , is a valuable aquaculture species in Korea , but spontaneous eye abnormality occurred in cultured individuals . The incidence of eye abnormality was 4% in the group of cultured red scebream. The abnormality was characterized by unilateral and bilateral exophthalmos, opacity and lens pathology. Lense prolapse was found in two cases. Lenses in diseased fishes was considerably small in diameter and eyes were deformed as a whole. In the group of induced hybrid red scabream Pagrus major (♀) x black seabrearn Acanthopagrus schlegeli (♂), the incidence of eye abnormality wa~ the same 4%, but only opacity was registered. Opacity was also found in two of sixteen examined Wild-caught red seabrcam. Histopathological changes of lenses in cultured red seabreem included vecuolated cytoplasm of lens fibers, necrosis of fibers in central part of lens, folding and increase in thickness of lens capsule, and epithelial proliferation beneath the anterior lens capsule. In affected eyes no parasites or gas bubbles were found.

• Journal of Aquaculture
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• v.16 no.3
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• pp.165-170
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• 2003

Isolation, cloning and sequencing of red seabream (Pagrus major) somatolactin (rsbSL) cDNA from pituitary gland revealed an open reading frame of 693 bp coding for a pre-growth hormone of 231 amino acids with a 22 amino acid putative signal peptide. Deduced amino acid sequence showed that there was one possible N-glycosylation site at Asn$^{145}$ and seven Cys residues (Cys$_{29}$ , Cys$^{39}$ , Cys$^{66}$ , Cys$^{89}$ , Cys$^{205}$ , Cys$^{222}$ , Cys$^{230}$ ). Except Cys$^{66}$ , others may be involved in disulfide bond formation. The rsbSL presented a 93% amino acid sequence identity with the SL of gilthead seabream (Sparus aurata) and contained the conserved hormone domain region. Expression of rsbSL in E. coli (BL2l) cells and gel analysis revealed a higher molecular weight for rsbSL than expected theoretically, implying posttranslational modifications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.785-792
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• 2013

Two studies were conducted to investigate the effects of dietary nucleotides (NT) on the growth performance, hematological parameters, and innate immune responses of red seabream Pagrus major. In Expt I, six experimental diets were formulated: a control, four that contained each NT at a level of 0.15% (inosine monophosphate, IMP; adenosine monophosphate, AMP; guanosine monophosphate, GMP; and uridine monophosphate, UMP), and one with a 1:1:1:1 mixture of NTs (IMP, AMP, GMP, and UMP). In Expt II, five experimental diets were formulated that contained 0, 0.1, 0.2, 0.4, and 1.0% IMP (commercial product). Triplicate groups of juvenile (initial body weight 33.1 g) and growing (initial body weight 120 g) red seabream were fed one of the experimental diets to apparent satiation for 8 weeks in Expt I and 12 weeks in Expt II. In Expt I, fish fed diets with NT had higher growth performance than the control group. The nitroblue tetrazolium and lysozyme activities were higher in fish fed the mixed-NT diet, and lowest in the control group. In Expt II, the final body weight and feed utilization of fish fed the 0.1% IMP diet were significantly higher than those of fish fed the control or 1.0% IMP diets. Diet palatability was improved significantly when 0.1% IMP was added. The lysozyme activity was higher in fish fed diets with 0.4-1.0% than in the control group. These results suggest that supplementation of 0.15% IMP and Mixed-NTs in diet can enhance the growth and immune responses in juvenile red seabream. The optimum IMP level appears to be 0.2% in practical feed formulation for growing red seabream.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.474-481
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• 2019

This study evaluated the chronic effects of $NO_3-N$ on juvenile blackhead seabream Acanthopagrus schlegelii. The experiment used six identically configured recirculating aquaculture systems (435 L), with three tanks (70 L) each. The $NO_3-N$ concentrations studied were 0 (control), 62.5, 125, 250, 500, and 1,000 mg/L $NO_3-N/L$. Thirty juvenile blackhead seabream ($18.8{\pm}2.2g$) were stocked in each tank. Growth and hematological changes were evaluated after 120 days. At the end of the experiment, the growth, survival, and cortisol levels indicated that blackhead seabream were healthy in 500 mg $NO_3-N/L$. However, insulin-like growth factor I (IGF-1) and the IGF-1 receptor were significantly lower at 250, 500, and 1,000 mg $NO_3-N/L$ than in controls (62.5 and 125 mg $NO_3-N/L$). Juveniles were likely affected at a much lower $NO_3-N$ concentration than 250 mg/L $NO_3-N/L$ in terms of IGF-1 and the IGF-1 receptor. Therefore, for the sake of long-term fish welfare, the $NO_3-N$ should be maintained at lower than 250 mg/L for blackhead seabream in recirculating aquaculture systems.

• Journal of Life Science
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• v.25 no.1
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• pp.16-20
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• 2015

During the storage of these two species in a large conservation tank, fertilized eggs were collected and the offspring were raised. During culturing of the offspring, individuals with mixed characteristics of these two species were observed, and 96 individuals were randomly tested using microsatellite markers applicable to both species. Among the 96 individuals, 15 individuals with mixed morphological characteristics were confirmed to be hybrids showing both of genotypes red seabream and blackhead seabream. Additionally, based on sequence analysis of mitochondrial cytochrome oxidase subunit 1 (mtDNA CO1), 81 showed 99% nucleotide sequence identity to that of black sea bream, and the remaining 15 individuals showed over 99% sequence identity to that of red seabream. So, hybrids were produced by female red seabream and male blackhead seabream. These results suggest that hybrids may form in nature between these two species if their habitats overlap due to the influence of humans or global climate change.

• Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.88-92
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• 2001

To examine effects of cadmium on the respiratory burst of kidney phagocytes and antioxidant defense in liver, juvenile red seabream Pagrus major were fed a cadmium-incorporated diet $(1g\;CdC1_2/kg\;diet)$. The respiratory burst activity measured by chemiluminescence (CL) was significantly reduced by oral intake of cadmium. Lipid peroxidation in liver expressed as thiobarbituric acid reactive substances (TBARS) was significantly higher in the fish fed a cadmium-incorporated diet than that of the fish fed a control diet both on Day 3 and Day 9. Liver Glutathione S-transferase (GST) activitiy was significantly increased both on Day 3 and Day 9 by feeding a cadmium-incorporated diet, when compared with the controls. From the present results, it can be concluded that oral intake of cadmium in red seabream is associated with marked reduction of respiratory burst capacity of kidney phagocytes which can elevate susceptibility of fish against infecting pathogens. Cadmium administration also elicits significant increment of lipid peroxidation in liver, and fish try to detoxify cadmium by increasing GST activity.

• Journal of Life Science
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• v.13 no.1
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• pp.34-41
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• 2003

The hatching of fertilized egg and early development of larval black seabream, Acanthopngrus schlegeli by immersion of 3,5,3'-triiodo-L-thyronine ($T_3$) with doses of 0.01~0.5 ppm in tank were examined for early development periods and compared with control fish immersed by 0.1 N NaOH and 99% alcohol. Larvae were fed with rotifers for first 5 days during experimental period. Yolk absorption of larvae from $T_3$ immersion groups were significantly faster than that of control. Although hatching times among each groups were not significant difference. the hatching rates of larvae in higher doses (0.1 ppm and 0.5 ppm $T_3$ groups) were significantly lower than control. The results of $T_3$ immersion experiments to newly hatching larvae indicated that exogenous $T_3$induced significant faster the absorption of yolk and oil globule, faster the development of myotome and digestive duct and higher the growth rate of larvae than larvae of control. These results indicate that $T_3$ immersion supplements appear to confer a distinct advantage to eggs and larvae of black seabream, which is in early fragile developmental stage.

• Journal of Aquaculture
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• v.13 no.3
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• pp.187-191
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• 2000

The effects of osmolality on the sperm motility in black seabream (Acanthopagrus schlegeli) were studied. Sperm motility of black seabream was suppressed when the osmolality was equal to the seminal fluid. But sperm became motile when the osmolality increased in electrolyte solution (NaCl, KCl, $CaCl_2$, $MgCl_2$) and non-electrolyte solution (mannitol, glucose, fructose, sucrose). The changes of sperm motility index (SMI) by osmolality of diluents described a parabola. In all of the diluents, SMI was the highest at ca. 1,000 mOsm/kg, which is similar to the osmolality of seawater. Sperm motility was induced by osmolality of diluents, but exposure to hypotonic or hypertonic diluents was harmful to the sperm.

• Journal of fish pathology
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• v.16 no.3
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• pp.165-173
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• 2003

A stable cell line, BSBS (black seabream spleen), was established from the cells in spleen of black seabream, Acanthopagrus schlegeli, and characterized. Subculture maintained more than 60 passages and mophologically, BSBS cell was epithelioid cell. The cells grew optimally at 20℃ in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum with incubation temperature of 20℃. BSBS cells supported the growth of marine birnavirus (MABV Y-6), chum salmon reovirus (CSV), spring viremia of carp virus (SVCV) and hirame rhabdovirus (HIRRV). Thus, the new cell line may be useful for studying wide range of fish viruses.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.130-137
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• 2011

Visual stimuli of nets, which affect fishing selectivity, vary by twine diameter, color, and material under different light conditions and visual geometries. In this study, two cylindrical model codends of two mesh sizes, 28 and 43 mm, were made of high-contrast, dark brown polyethylene (PE) netting twine and low contrast, light-blue polyamid (PA) monofilament twine. Each model codend was filled with juvenile seabream and set in the water channel of a light-blue circular tank under a flow speed 0.8 m/s for 30 min. Light conditions were set to relatively bright, dim, and dark. The resulting retention rates of juvenile seabream were 15-35% lower for the low-contrast codend with PA monofilament than for the high contrast PE twine netting under bright and dim light conditions, while no difference was observed under dark conditions. The effects of mesh size and netting contrast on the retention rate were dependent on the light level, while the retention rate due to netting contrast was independent of mesh size. Therefore, low-contrast nets in the codend could help to reduce juvenile bycatch by disturbing the orderly optomotor response.