• Fisheries and Aquatic Sciences
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• 제14권4호
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• pp.339-345
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• 2011

Although culture techniques for the abalone Haliotis discus hannai are well known, mass culture of the benthic microalgae that are essential live food for the abalone larvae is still not practiced. This study was conducted to identify the microalgal species suitable for the growth of early larvae of H. discus hannai. The growth and attachment rates of 31 microalgal species were examined. Acrylic plates were used as the substrate. Among the 31 microalgal species, nine showing high growth and attachment rates were selected and tested for their dietary values via factors including settlement, metamorphosis, and survival rates of abalone larvae. Tetraselmis hazeni and Rhaphoneis sp. induced the highest settlement rate (65-69%) in abalone larvae. The metamorphosis rate was highest (57%) in larvae fed Rhaphoneis sp. and was also significantly higher in larvae fed Oscillatoria splendida (29%) and T. hazeni (22%) than in those fed other species. The highest survival rate of the larvae during the 15 days after metamorphosis was 67% in those fed Rhaphoneis sp., followed by T. hazeni (42%) and O. splendida (35%). In conclusion, Rhaphoneis sp. is the most suitable diatom for use as a live food for the culture of early larvae of H. discus hannai. In addition, T. hazeni and O. splendida are also potential species to be further developed and utilized in larval culture.

• Parasites, Hosts and Diseases
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• 제49권1호
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• pp.51-57
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• 2011

Four cases of gastric or intestinal myiasis are reported. The cases contain 2 males (1 child 10 years old, and 1 adult 40 years old) and 2 females (1 girl 18 years old, and 1 adult 50 years old) from Minia Governorate, Southern Egypt. Three of them, including cases no. 1, 3, and 4, were gastric myiasis, and complained of offensive hematemesis of bright red blood. Minute moving worms, larvae of the fly, were found in the vomitus. On the other hand, case no. 2 had intestinal myiasis, and complained of abdominal distention, nausea, vomiting, and diarrhea. The stool of case 2 was mixed with blood, and minute moving worms were observed in the stool. Endoscopy was performed to explore any pathological changes in the stomach of the patients. The larvae were collected and studied macroscopically, microscopically, and using a scanning electron microscope (SEM) to identify their species. Three different types of larvae were identified. The larvae isolated from case 1 were diagnosed as the second stage larvae of Sarcophaga species, and the larvae isolated from case 2 were the third stage larvae of Sarcophaga species. On the other hand, the larvae isolated from cases 3 and 4 were diagnosed as the third stage larvae of Oestrus species.

• Fisheries and Aquatic Sciences
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• 제8권4호
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• pp.228-234
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• 2005

Despite the relatively high production of fingerlings of the olive flounder Paralichthys olivaceus, its larval rearing in terms of first feeding has not been fully analyzed. We evaluated the variations of amino acids and fatty acids of starved larvae over 96 hr after hatching. We also investigated depletion of the yolk and oil globule of starved larvae and those fed the rotifer Brachionus plicatilis. In addition, the optimum size of the rotifers according to the mouth size of the larvae, and the point of no return with delay of the first feeding, were also examined. The amino acids in the egg decreased abruptly during embryo development. At 48 to 72 hr after hatching, the amino acids of starved larvae decreased by $30-40\%$ from the level in newly hatched larvae. The concentrations of fatty acids in newly hatched larvae were lower than those of floating eggs and dropped sharply at 48 hr after hatching, when the yolk disappeared. The starved larvae depleted their yolksacs and oil globules earlier than the fed larvae did. At 84 hr after hatching, rotifers were detected for the first time in the guts of the larvae, which were about 3 mm in total length. The point of no return appeared to be close to the fourth day from the first feeding. For a high survival rate of P. olivaceus larvae, the first feeding should occur before the third day after hatching.

• 한국환경과학회지
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• 제32권9호
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• pp.671-674
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• 2023

This study was conducted to evaluate the effects of using Hermetia illucens larvae as environmental purification insects on ammonia and Hanwoo manure for 15 days in the Hanwoo farms. H.illucens larvae were allocated into four treatment groups and three replicates using a randomized block design. The treatments were as follows: control, normal 1000 g of Hanwoo manure, T1, 1000 g of Hanwoo manure + 100 g of 2nd instar H.illucens L. larvae, T2, 1000 g of Hanwoo manure + 100 g of 3rd instar H.illucens L. larvae, and T3, 1000 g of Hanwoo manure + 100 g of 4th instar H.illucens L. larvae. After 0 days, ammonia fluxes did not occur in the 2nd, 3rd, and 4th instar H.illucens larvae treatments (p<0.05). Among the characteristics of Hanwoo manure, the pH and nitrogen content increased for each larvae instar of H.illucens, whereas ADF and NDF content decreased (p<0.05). In particular, nitrogen contents were found to be highest in the 3rd instar larvae of H.illucens owing to their greater ability to decompose Hanwoo manure than larvae at other growth stages.

• The Korean Journal of Ecology
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• 제28권4호
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• pp.193-198
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• 2005

This study investigated the characteristics of the eggs and yolk sac larvae of Korean striped bitterling, Acheilognathus yamatsutae, spawned and grown In mussels. The number of eggs in the ovary was small ($358{\pm}108$ SD). The eggs were oval and large, and the formation of the perivitelline space was narrow. The eggs were hatched at only 41 hours after fertilization but the hatched larvae were underdeveloped. The development of yolk projection and minute tubercles on the skin surface was notable, along with the vividly moving tail in the hatched larvae. The yolk projection and minute tubercles were disappeared upon enhancement of the motor ability of the larvae was enhanced. The formation of eyes and body pigments of the larvae was relatively delayed in comparison with that of other cyprinid larvae. After completely consuming the yolks the larvae escaped from the mussel for free swimming and exogenous feeding.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.417-420
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• 2015

We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M dimethyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrification. After immersion into VSs and freezing, IGF-1R ${\beta}$-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular ${\beta}$-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability.

• 수산해양교육연구
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• 제28권1호
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• pp.180-185
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• 2016

두줄망둑 자치어기의 먹이생물을 조사하기 위하여 2012년 5월말부터 6월초 사이에 충남 서천군 서면 도둔리의 조간대에서 채집된 두줄망둑의 위내용물을 조사하였다. 섭식참여율은 낮 동안에 오전과 오후에 각각 한 차례씩 증가하는 경향을 보였다. 두줄망둑의 자치어의 주요 먹이생물은 copepods, amphipods, shrimp larvae, polychaete larvae 등이었으며, 이들이 건중량의 2% 이상을 차지하였다. 그중에서 copepods가 평균 65.5%로 가장 많은 양을 차지하였고, polychaete larvae, shrimp larvae 등의 순으로 많이 출현하였다. 먹이생물의 개체수 조성비를 보면, copepods가 65.4%를 차지하여 가장 높았고, polychaete larvae는 22.6%, shrimp larvae는 14.5%를 차지하였다. 먹이생물 중 copepods는 개체수 조성비가 높고 출현율도 높아서, IRI가 5,369.3으로 가장 높은 수치를 나타내었고, polychaete larvae는 653.1, shrimp larvae는 287.1의 수치를 나타내었다. 따라서 두줄망둑의 자치어기의 가장 중요한 먹이생물은 copepods, polychaete larvae, shrimp larvae 등이었다.

• Parasites, Hosts and Diseases
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• 제35권3호
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• pp.211-214
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• 1997

중국산 수입 미꾸리에서 검출한 돼지악구충(Gnothostoma hispidum)의 유충(early third-stage larvae: EL3)을 10∼20개씩 비단잉어, 가물치 황소개구리. 마우스 및 흰쥐 등에 각각 경구 감염시킨 후 감수성을 관찰하였다. 총 40마리 및 45마리의 유충을 감염시킨 비단잉어 4마리와 가물치 3마리에서는 충체가 한 마리도 검출되지 않았다 유충을 총 30마리 감염시킨 황소개구리 3마리에서는 감염 후 2주에 위 및 장(8마리)과 간(1마리)에서 각각 검출되었는데 미꾸리에서 검출된 것과 같은 EL3이었다. 마우스 5마리에 유충을 각각 10마리씩 감염시키고 4주 후에 감염여부를 검사하였던 바. 총 37마리(74%)가 근육(31마리), 간(5마리). 신장(1마리) 등에서 검출되었다 유충 115마리를 흰쥐 9마리에 감염시키고 4주 및 8주 후에 충체를 회수하였던 바 총 40마리(34.8%) 가 모두 근육에서 검출되었다 이상의 결과로 중국산 수입 미꾸리에서 검출한 돼지악구충의 제3기 유충이 어류나 개구리에서 보다 마우스와 흰쥐에 더 잘 감염됨을 알 수 있었다.

• Parasites, Hosts and Diseases
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• 제23권2호
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• pp.247-252
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• 1985

In the present study, the effect of primary infection to reinfection with Ascaris suum larvae was experimented in mouse model. Mice were challenged with 1,000 infective stage eggs of Ascaris suum. The embryonated eggs were directly introduced into stomach of mice. Reinfection was performed at 50 days after the primary infection with same method as primary infection. Mice were sacrificed 3, 5, 7, 10, 15 and 20 days after infection in both groups respectively. Larvae collected from livers and lungs with Baermann's apparatus were enumerated and measured after sacrifice. Sera of mice were also collected at same time. The results of the experiment were as follows: With antigen prepared from coelomic fluid of adult Ascaris suum and sera collected from mice before reinfection, the production of antibody in experimental mice was confirmed by the gel-diffusion technique. In the livers of reinfected mice, the larvae were recovered up to 10 days after challenge, otherwhile in the primary infected mice, the larvae were observed up to 7 days. The maximum number of larvae were observed in the lungs of primary infected mice on 10 days after inoculation. In the lungs of reinfected mice, maximum number of larvae were recovered on 7 days after, only few larvae were recovered on 10 days after reinfection. As regards the growth of the larvae, the third stage larvae, over $500{\mu\textrm{m}}$ in length, appeared in livers at 5 days after reinfection, but it couldn't be found on 7 days and 10 days after challenge. The third stage larvae continuously developed were observed in lungs of mice from 5 days after reinfection. In conclusion, it was found that development of larvae in livers of immune mice were probably repressed by the immune mechanisms being rises in livers and defence mechanism is also acting by interfering with the process of larval penetration into the lung from the liver.

• 한국수산과학회지
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• 제35권5호
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• pp.542-544
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• 2002

This study was carried out to evaluate the ciliates Euplotes sp. as a live food for marine fish larvae. The ciliates and the rotifers Brachionus plicatilis, which were cultured with the baker's yeast Saccharomyces cerevisiae and the $\omega$-yeast emulsified with cuttle fish liver oil, were supplied to the larvae of flounder Paralichthys olivaceus and grouper Epinephelus akaara. Considering the size difference between the ciliates 68 $\cdot$ 7 $\mu$n and the rotifers 160 $\cdot$ 20 $\mu$n, the rotifers and ciliates were supplied to the larvae tank with the density of 2 inds./mL and 20 inds./mL, respectively. The survival rate and growth in length of the flounder larvae fed on rotifer were significantly higher than those on Euplotes sp.. In grouper larvae which have a small mouth diameter, even the survival rate of the larvae fed on the ciliates was better than that on the rotifers, it was very low less than $20\%$. Therefore, Euplotes sp. seem to be incongruent as a live food for marine fish larvae.