• The Korean Journal of Malacology
• /
• v.32 no.1
• /
• pp.1-7
• /
• 2016

The developmental stage of germ cells during oogenesis can be categorized into six stages with histological features: (1) oogonium, (2) previtellogenic oocyte, (3) initial vitellogenic oocyte, (4) early active vitellogenic oocyte, (5) late active vitellogenic oocyte and (6) ripe oocyte. The size of oocyte, nucleus and nucleolus illustrated the increase tendency but size ratio of nucleolus to nucleus was decreased during oogenesis. During oogenesis the stainability in the cytoplasm of oocyte changes from basophilic to eosinophilic in H-E stain. And egg stalk and outer jelly membrane was developed in the oocyte. These histological changes are seemed to be yolk accumulation in the oocyte and preparation process for spawning.

• Journal of fish pathology
• /
• v.22 no.3
• /
• pp.293-303
• /
• 2009

Effects of stress on the low salinity stress were examined in the pacific abalone Haliotis discus discus. Changes in survival rate, hemolymph count, antioxidant enzyme activities (catalase: CAT and superoxide dismutase: SOD), respiratory burst activity, phenoloxidase activity, lysozyme activity and expression of heat shock protein 70 (HSP70) mRNA were measured 0, 3, 6, 12, 24 or 48hours after low salinity treatment with 25, 30, 33 and 35 psu. Survival rates of pacific abalone were 100% at 33 and 35 psu, but 93 and 97% at 25 and 30 psu for 48 hours, respectively. Hemolymph counts decreased in the time elapsed-dependent way at all of the experimental groups. At low salinity, 25 and 30 psu, SOD and CAT activity increased compared to the experimental group of 33 psu. Moreover, respiratory burst activities of the pacific abalone seemed to have no effect on low salinity stress at any experimental group. However, phenoloxidase activity is an important component of the defence against pathogen that was decreased in a reduction of salinity dependent way. Lysozyme activity also immediately reduced at 25 psu experimental group for 48 h. The HSP70 mRNA was weakly expressed at 33 psu, but strongly detectable at 25 psu experimental group. The HSP 70 mRNA expression in gill increased in the time elapsed-dependent way at 25 psu experimental group and then recovered at 48 h. These results suggest that low salinity stress give rise to inhibitory action of immune system as a result of the decrease of phenoloxidase and lysozyme activity in the pacific abalone, especially.

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.3
• /
• pp.223-231
• /
• 2020

Karyotype analysis is a major work in the process of triploid abalone production for the purpose of productivity and quality improvement. However, the metaphase spreads for karyotype analysis have been prepared just from the larvae at trochophore stage, which has restricted the spectrum of sample correction inhibiting more efficient analysis. Here, we investigated the feasibility of preparing metaphase spreads from the larvae at veliger stage that is the next developmental stage of trochophore. For this, diploid and triploid larvae at trochophore and veliger stages from Pacific abalone (Haliotis discus hannai) were subjected to metaphase spread preparation and its efficiencies were measured and compared each other. As the results, although the efficiencies of metaphase spread preparation were significantly lower in the larvae at veliger stage compared to the ones at trochophore stage regardless of ploidy status, we found that the preparation of metaphase spreads, which showed the clear chromosomal images containing the normal number of chromosomes, was possible from the veliger stage larvae. On the other hands, all larvae used in this study regardless of developmental stage and ploidy did not show colchicine sensitivity. Moreover, no significant difference was observed in cell cycle distribution of the cells comprising larvae between two developmental stages regardless of ploidy status. These suggested that the details of protocol to prepare metaphase spreads from abalone larvae should be optimized depending on its developmental stages. Taken together, we demonstrated the feasibility of preparing metaphase spreads from H. discus hannai veliger stage larvae for karyotype analysis.

• Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.249-253
• /
• 2014

An 8-week feeding experiment was conducted to determine the influence of dietary distillers dried grain (DDG) on the growth and body composition of juvenile abalone Haliotis discus hannai. Five diets were formulated to contain 0% (DDG0), 15% (DDG15), 30% (DDG30), 45% (DDG45), and 60% (DDG60) DDG, and three replicate groups of abalone (average body weight: $3.6{\pm}0.21$ g) were fed one of the experimental diets at a feeding rate of 5% body weight per day once daily (17:00 h) for 8 weeks. Survival, shell length, and shell width of juvenile abalone were not affected by dietary DDG levels (P > 0.05). Weight gains of juvenile abalone fed DDG15 and DDG30 diets were not different compared to DDG0, but abalone fed DDG45 and DDG60 diets gained less weight than those fed DDG0 (P < 0.05). Soft body weight/body weight ratio of juvenile abalone fed the DDG60 diet was lower than that of those fed the DDG0 diet (P < 0.05), but proximate composition of the soft body was not affected by dietary DDG levels (P > 0.05). The results of this experiment suggest that DDG is a good replacement for wheat flour and soybean meal, and can be used up to 30% in the diet to maintain the growth performance of the juvenile abalone.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.40 no.3
• /
• pp.133-140
• /
• 2007

In 2006, we studied herbivore consumption rate and preference for algal species using laboratory experiments. In the no-choice feeding experiment, three herbivores (two sea urchins, Stronglyocentrotus nudus and Stronglyocentrotus intermedius and an abalone, Haliotis discus hannai) showed significantly (P<0.05) distinct preferences for four algae (Laminaria japonica, Undaria pinnatifida, Costaria costata and Ecklonia stolonifera). The alga preferred by S. nudus was L. japonica followed by U. pinnatifida, C. costata and E. stolonifera with respective daily feeding rates of $5.7{\pm}:0.85\;g,\;4.4{\pm}0.89\;g,\;3.1{\pm}0.39\;g\;and\;2.1{\pm}0.32\;g(mean{\pm}SE)$. A similar trend was found for S. intermedius. Interestingly, the herbivore consumption rates for the algae differed with or without competition. The competition stimulated the feeding activity for S. nudus, but lowered the activity for S. intermedius. The multi-choice feeding experiment confirmed that L. japonica was significantly preferred by two herbivores: S. nudus and H. discus hannai (Duncan's multiple range test, ANOVA, p<0.05).

• The Korean Journal of Malacology
• /
• v.31 no.2
• /
• pp.83-92
• /
• 2015

The effect of different intermediated rearing method by expanding the attached floor space in order to highly density culture on the growth characteristics and survival rate of the juvenile abalone, Haliotis discus hannai, were investigated in land-based tanks. The intermediated culture methods was determined thru the shelter counts and layer for 10 month with two replicates : the single layer shelter (SLS), the double layer shelter (DLS), the triple layer shelter (TLS) and the single layer shelter under net cage (SLSNC). In addition, the culture on shallow race way tank had to set up as culture of the ditch raceway tank (CDRT) and the floor race way tank (CFRT). In the growth performance of reared abalone (initial mean shell length $54.18{\pm}7.39mm$ and weight $1.93{\pm}0.14g$) at experimental tanks, that the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rate (SGR) to the shell length and shell breadth was not significant at each experimental tanks except SLSNC. As well as too, weight gain (WG), daily weight gain (DWG) and specific weight gain (SWG) to weight was not significant at each experimental tanks except SLSNC, too. Survival rates of CDRT and CFRT was lower than those of different experimental tanks (P < 0.05). Therefore, these results is showed that high density different intermediated rearing method by expanding the attached floor space for juvenile H. discus hannai was not have difference as growth performance and survival rate both one layer shelter and multi layer shelter. Also, it is considered that shallow race way tank was not useful rearing for the juvenile intermediate culture of H. discus hannai in land based.

• Journal of Life Science
• /
• v.19 no.8
• /
• pp.1003-1008
• /
• 2009

Abalone (genus Haliotis) is a woody species with a long life span that is primarily distributed throughout the world, including Asia. This species is regarded as a very important marine gastropod mollusk in Korea and China, and also in food industries around the world. We evaluated a representative sample of the five species with nuclear ribosomal DNA internal transcribed spacer sequences (ITS) to estimate genetic relationships within the genus. Aligned nucleotide sequences of the length of the 5.8S subunit of all taxa of Haliotis were found to constant of 160 bp nucleotides. However, aligned nucleotide sequences of the length of ITS1 were varied within genus Haliotis, varying from 272 in H. diversicolor aquatilis to 292 in H. discus hannai. Aligned nucleotide sequences of the length of ITS2, especially, vary from 722 in H. diversicolor aquatilis to 752 in H. sieboldii. Total alignment length is 763 positions, of which 78 are parsimony-informative, 57 variable but parsimony-uninformative, and 459 constant characters. H. discus hannai was similar to H. discus, while H. diversicolor aquatilis was more distinct. ITS analysis may be useful in germ-plasm classification several taxa of genus Haliotis.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2005.05a
• /
• pp.76-77
• /
• 2005

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.2
• /
• pp.100-105
• /
• 2005

Two species of fish and five species of marine invertebrate showed different tolerances to the toxicity of composite slag and bituminaus coal. Especially, Hemicentrotus pulcherrimus and young Haliotis discus hannai displayed marked differences in tolerance from. H. pulcherrimus and young H. discus hannai showed lethal effects at higher concentrations than those concentrations of the composite slag in the 1.0 and $0.4\%$ range, respectively. H. pulcherrimus showed no lethal effects at a lower concentration of $1.0\%$ composite slag and some differences in the rate of oxygen consumption with this concentration of composite slag. The lethal effects of bituminous coal on marine and fisheries organisms, even with higher concentrations, were not observed. At a higher concentration than that of 500 mg/L (ppm) of bituminous coal, decrease effects appeared in the rate of oxygen consumption of the experimental organisms. Taking into consideration that the experimental concentration of composite slag and bituminous coal were impracticable in the ocean, the results of this experiment suggest that composite slag and bituminous coal pose no real threat to marine or fisheries organisms.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2003.10a
• /
• pp.74-74
• /
• 2003

In present study, attempts were made to preserve abalone (Haliotis discus hannai) sperm in liquid form at low temperature, to evaluate the effect of various diluents in short-term storage on sperm, and cryopreservation procedures were optimized for the cryoprotectants as well as freezing rates, in terms of the motility and survival rate, and the ultrastructural changes of sperm after short-term storage and cryopreservation were observed. The abalone sperm reached maximum motility until about 4min after activation. The motility was constant for about 16min, after which it dropped gradually, and about 50min later all motility ceased. Threshold activation of sperm was found in 40% artificial seawater (ASW), and motility increased as the concentration of ASW increased. In Hanks balanced salt solution without calcium (Ca-Free HBSS, 300 and 400 mOsmol/kg) and 10%, 20%, and 30% ASW the sperm was immotile, and motility once again restored incompletely only in HBSS of 300 and 400 mOsmol/kg, 20% and 30% ASW after 100% ASW was added. Sperm motility was extended following 20 days of cold storage only in 70% and 100% ASW. A high motility index of 3.5-4.5 was observed for the first 8 days in 70% and 80% ASW. In other diluents sperm motility was constant less than 10 days, and the motility index was obviously lower than that of sperm in 70% and 100% ASW. After 20 days of cold storage survival rates of 10.2%-20.7% were obtained in ASW and 300 mOsmol/kg HBSS, and that in 400 HBSS (65.3%) was significantly higher than others. The constant period of sperm motility stored in 70% ASW was longer obviously than that in 100% ASW after 6 days of storage, and the time to maximum motility of sperm stored in 70% increased gradually, while the difference in which of sperm in 100% ASW was not significant. The sperm plunged into liquid nitrogen all died except that sperm using 15% glycerol as cryoprotectant restored 10.4% of motility. The highest motility index (3.4) was obtained with 5% glycerol and freezing procedure: $50^{\circ}C$/min from $20^{\circ}C$ to $-80^{\circ}C$.