• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.90-97
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• 2020

The purpose of this study was to provide basic information on sexual maturity and reproductive biology for the management of biological resources in abalone Haliotis discus hannai. The nucleus of the oogonium occupied about 42% of the cytoplasm, and had a distinctive basophilic chromatin. The cytoplasm of previtellogenic oocytes was homogeneous and the size of nuclear pores increased. Fine granular and vacuolar yolk granules were observed in the cytoplasm of the initial vitellogenic oocyte. In this stage, the egg stalk and jelly membrane began to develop. The nucleus of the active vitellogenic oocyte was located near the animal pole. Yolk granules were strongly acidophilic. Lampbrush chromosomes were observed in the nucleus and rough endoplasmic reticulum. Annulate lamellae developed in the cytoplasm. The shape of the ripe oocyte was rounded polygonal. The size of ripe oocytes was 202.9±21.40×142.1±18.82 ㎛ and the thickness of the jelly membrane was 10.1±1.52 ㎛. These results show that yolk accumulation in H. discus hannai is based on two methods: exogenous accumulation, through the egg stalk, and endogenous accumulation, through intracellular organelles. Management of biological resources will be necessary when oocytes predominate after the active vitellogenic stage.

• The Korean Journal of Malacology
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• v.31 no.4
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• pp.273-277
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• 2015

This study was conducted to provide the reproductive biological information and basic data on the artificial sex control of Haliotis discus hannai. The morphological sex differentiation process of H. discus hannai could be classified into following five phases: 1) formation of gonad outer membrane (FGOM) (${\leq}SL\;10.0{\pm}1.0mm$), 2) primordial germ cells (PGCs) appearance in the connective tissue between intestine and hepatopancreas (PAC), and formation of gonadal cavity (FGC) (SL $15.0{\pm}2.0mm$), 3) PGCs appearance in the epithelial layer of gonadal cavity (PAG) (SL $18.0{\pm}2.0mm$), 4) formation of gametogenic follicle and appearance of early oocytes and spermatogonia (FGOC) (SL $21.0{\pm}2.0mm$), 5) morphological sex differentiation (MSD) (${\geq}SL\;23.0{\pm}2.0mm$). From histological analysis sex differentiation rate in SL 24.1-25.0 mm of H. discus hannai was 90.0% and sex ratio (female : male) was 1:0.8.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.193-199
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• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.

• Journal of Life Science
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• v.24 no.12
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• pp.1291-1300
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• 2014

Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant enzymes that participate in a variety of biological processes, including $H_2O_2$-mediated signal transduction, molecular chaperoning, and mitochondrial function. In this study, we isolated and characterized a Prx 2 cDNA from abalone (Haliotis discus hannai). The abalone Prx 2 cDNA encoded a 199-amino acid polypeptide that belongs to a class of typical 2-Cys Prxs that contain peroxidatic and resolving cysteines. The deduced abalone Prx 2 protein showed strong homology (64-99%) with Prx 2 proteins from other species, including mollusk, fish, amphibians, and mammals, and it was most closely related to disk abalone (H. discus discus) Prx 2. Abalone Prx 2 mRNA was ubiquitously detected in tested tissues, and its expression was comparatively high in the mantle, gills, liver, foot, and digestive duct. The expression level of abalone Prx 2 mRNA was 106.7-fold, 51.9-fold, and 437.8-fold higher, respectively, in the gills, digestive duct, and liver than in the muscles. The expression level of abalone Prx 2 mRNA in the liver peaked at 6 hr postinfection with Vibrio parahemolyticus and decreased at 12 hr postinfection. The expression level of abalone Prx 2 mRNA in hemocytes was drastically increased at 1 hr postinfection with V. parahemolyticus. These results suggest that abalone Prx 2 is conserved through evolution and that it may play a role similar to that of its mammalian counterpart.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.216-223
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• 2010

Abalone (Haliotis discus hannai), mostly distributed and maricultured in southwestern coastal areas of South Korea, is recognized as an economically important species in the fishery industry. Abalone intestines are one of the by-products of abalone processing. To investigate abalone intestines as bioactive substances, abalone intestine gastrointestinal digests (AIGIDs) of various molecular weights (MWs) were prepared using in vitro gastrointestinal digestion and an ultrafiltration system, and tested for inhibitory effects against reactive oxygen species (ROS) and oxidative stress in macrophage cells treated with hydrogen peroxide ($H_2O_2$). In our results, among AIGIDs, AIGID-III (MW=5-10 kDa) showed potent inhibitory activities for lipid peroxidation and free radicals. Additionally, the results clearly indicated that AIGID-III treatment could prevent cytotoxic damage of macrophages by $H_2O_2$-induced oxidative stress due to its potent scavenging ability against cellular ROS. These results suggest that AIGIDs may have protective and therapeutic potential for oxidative stress syndromes and immune diseases through ROS inhibition in macrophage cells.

• The Korean Journal of Malacology
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• v.31 no.3
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• pp.233-241
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• 2015

Toll-like receptors (TLRs) are a major pattern recognition receptor that recognize the structure of invading pathogen and play key roles by triggering immune response. In this study, we identified a sequence of TLR homolog and characterized at molecular level from the abalone (Haliotis discus hannai). Multiple alignments and phylogenetic analysis of abalone TLR protein belongs to the TLR 2/6. Expression level of abalone TLR 2/6 in the tissue was comparatively high in the mantle, gill, digestive duct, and hemocytes, but lowest in the muscle. Expression level of abalone TLR 2/6 mRNA in the mantle, gill, digestive duct, and hemocytes was 20-fold, 60-fold, 115-fold, 112-fold higher than in the muscle, respectively. Expression level of abalone TLR 2/6 mRNA in the mantle was steadily increased until 12 h and decreased post-infection with Vibrio parahemolyticus. While the expression level of abalone TLR 2/6 mRNA in the gill and hemocytes was drastically increased at 6 and 9 h post-infection with Vibrio parahemolyticus, respectively. These results suggest that abalone TLR 2/6 is conserved through evolution and may play roles similar to its mammalian counterparts.

• Fisheries and Aquatic Sciences
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• v.24 no.2
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• pp.89-98
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• 2021

The accumulation of ammonia, a consequence of intensive aquaculture activity, can damage cultured animals. We analyzed the survival rates, growth, antioxidant responses, and immune responses of abalones, Haliotis discus hannai (mean shell length 70.2 ± 4.9 mm; mean body weight 36.9 ± 3.6 g), biweekly for four weeks, to determine the accumulated concentrations of ammonia (0, 0.1, 0.2, 0.4, 0.8, and 1.6 mg/L). In our biweekly measurements, a survival rate of ≥ 95% was observed for all concentrations of ammonia. The specific growth rate (SGR) decreased at ≥ 0.8 mg/L (p < 0.05), but the daily increment in shell length (DISL) showed no significant change (p < 0.05). Regarding antioxidant responses, the superoxide dismutase (SOD) activity of the hepatopancreas was increased at ammonia concentrations over 0.8 and 0.2 mg/L (p < 0.05) at two and four weeks, respectively, and the SOD activity of the gills increased at concentrations over 0.4 and 1.6 mg/L (p < 0.05) at four weeks. The catalase (CAT) activity of the hepatopancreas and gills increased at ammonia concentrations > 0.8 mg/L (p < 0.05). Phenoloxidase (PO) activity increased at ammonia concentrations over 0.8 mg/L (p < 0.05), and Lysozyme (LZM) increased at concentrations over 0.8 and 0.4 mg/L (p < 0.05). Overall, our findings indicated that ammonia concentrations over 0.8 mg/L in seawater might damage the SGR, antioxidant responses, and immune responses in H. discus hannai. Our findings suggest the necessity of improvement or reinstallation for abalone aquaculture systems and can be used to assess the toxic effects of ammonia on H. hannai.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.91-96
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• 2013

Although the method of seedling production of Haliotis discus hannai is well known, the optimum benthic diatom species as a live food at early larval stage are not fully developed. In this study three Pennales diatom species, Caloneis schroederi, Rhaphoneis sp., and Cocconeis californica were examined on settlement, metamorphosis, survival, and growth of Haliotis discus hannai larvae. The larvae fed Raphoneis sp. or C. californica showed high settlement rate with 80-82% within 48 hrs, which was significantly higher than those fed C. schroederi or mixed diets with three diatom species. The larvae fed the former microalgal species also showed higher metamorphosis rate with 32-34% than the latter species with 10-12% within 4 days. With regard to survival and growth of the larvae, single diet with Rhaphoneis sp. or C. californica had better dietary value than the mixed diets for the early larvae of H. discus hannai.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.383-390
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• 2014

The multiplex PCR system including six microsatellites from Haliotis discus hannai, consisting of dinucleotide and trinucleotide repeat units, is developed. The six loci were coamplified in a single reaction employing dye-labeled primers. Alleles from these loci were sized using an internal standard by automated sample processing in an ABI3100 Genetic Analyser. Amplified alleles in profiles containing selected microsatellites were typed clearly, providing easily interpretable results. In this results suggest that the presented multiplex PCR system may be a useful tool in a selective breeding program of H. discus hannai in which genetic identification will allow different genotypes to be reared together from fertilization. This should have a great impact as it will make selective breeding more efficient. Moreover, it will be useful in a variety of applications, including strain and hybrid identification, parentage assignment, pedigree reconstruction, estimating genetic diversity and/or inbreeding.

• Journal of Aquaculture
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• v.9 no.2
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• pp.109-115
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• 1996

Tagging method, recapture frequencies and mortalities were investigated to obtain the basic data for the effective release technique of abalone, Haliotis discus hannai. Tagged and untagged H. discus hannai were reared for 90 days in the laboratory. Attachment of plastic piece by Alteco was used as tag material. The growth, mortality and falling rate of tags were examined. Data from stock in natural condition showed that fishing rate, fishing mortality and natural mortality of tagged group were 0.04, 0.0195 and 0.4652, respectively.