• 한국수산과학회지
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• 제54권4호
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• pp.426-433
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• 2021

This study aimed to determine the appropriate salinity condition for optimal cultivation of the juvenile hybrid grouper Epinephleus akaara♀×E. lanceolatus♂ in conditions of decreasing salinity. The survival, growth, metabolic rate, stress, and histological response were investigated in juvenile hybrid grouper exposed to different salinities for 30 days. At 0 psu, the survival rate of the juvenile hybrid grouper was 60% on the 2nd day of exposure and all individuals died on the 3rd day of exposure. At salinities above 3 psu, all animals survived throughout the exposure period. Growth rate for body weight of the juvenile hybrid grouper was the highest in the control and the lowest at 10 psu. Plasma osmolality of the juvenile hybrid grouper exposed to different salinities was 313-355 mg Osmol/kg at salinities above 10 psu, and then decreased to 225-264 mg Osmol/kg at salinities below 5 psu. The oxygen consumption rate tended to decrease as the salinity decreased. Stress responses of the juvenile hybrid grouper were analyzed with decreasing salinity. Therefore, it is considered that a salinity of more than 20 psu is suitable for the culture of the juvenile hybrid grouper.

• 한국수산과학회지
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• 제42권6호
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• pp.585-590
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• 2009

The purpose of this study was to examine the effects of oral-administered sex hormone for hybrid sturgeon, bester juvenile. The bester juveniles (2 months after hatching) were received a diet containing various doses of $17\alpha$-methyltestosterone (MT) or estradiol-$17\beta$ ($E_2$) for 6 months. Somatic growth of bester sturgeon juvenile did not show significant differences between experimental and control groups (27.9-30.5 cm; 125.1-161.7 g), although survival percentages showed a decreasing tendency in MT-treated animals. By histological examination, germ cells were recorded as smooth type in MT-treated fish and uneven type of germinal epithelium in $E_2$-treated animals. Their sex ratios were 5:4:1 (male: female: undifferentiation) in control and low dose of MT-treated fish (1 mg/kg), and 9:1:0 in fish treated with high dose of MT (10 mg/kg), whereas the ratios were reversed by both low and high doses of $E_2$ treatment, recorded as 2:8:0. Gonadal areas were not significantly differed in all trials (424,600.4 - 1,039,656.3 ${\mu}m^2$). Total number of germ cells, number of germ cells per gonadal areas and number of germ cells per area were significantly higher to 144.7-148.7 cells/section, 374.0-408.5 $cells/mm^2$ and 1,599.5-1,670.9 $cells/mm^2$ in $E_2$ treatment than those of others (30.4-63.9 cells/section, 148.4-226.9 $cells/mm^2$ and 850.0-1,050.6 $cells/mm^2$), respectively. And somatic growth according to their gender was not significantly differed between male and female.

• 한국수산과학회지
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• 제44권5호
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• pp.560-564
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• 2011

Two feeding experiments were conducted to investigate the effects of dietary inclusion of genetically modified (GM) soybean and corn on the growth performance, feed utilization and body composition of juvenile abalone Haliotis discus hannai. Four isonitrogenous (31% crude protein) and isolipidic (6% crude lipid) diets (designated as nGM-soya, GM-soya, nGM-corn and GM-corn) were formulated to contain 20% non-GM (nGM) and GM soya and corn. Fifty juvenile abalone (initial body weight, 2.0 g) were distributed in each 50 L tank in a flow-through system. Each experimental diet was fed to duplicate groups of abalone to satiation once a day for 10 weeks. No effects of GM feedstuffs on survival were observed. Dietary inclusion of GM feedstuffs did not affect either growth performance or feed utilization of abalone. Body composition was not altered by the inclusion of GM feedstuffs. These results indicate that dietary inclusion of GM soybean and corn could have no effect on the growth performance and body composition of juvenile abalone. Further studies to investigate the effects of GM feedstuffs on transgenic fragment residues in ambient environments and in animals are necessary for the safe use of such ingredients in aquaculture.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.144-145
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• 2001

Marine microalgae are used extensively in mariculture as food for marine animals, in particular larval and juvenile molluscs, crustaceans and fish. A wide range of microalgae has been tested, because not all species are equally successful in supporting growth of a particular animal. In addition, bioactivities of marine microalgae are recently investigated for the effective exploitation of unutilized marine resources. (omitted)

• 한국양식학회지
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• 제16권4호
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• pp.223-228
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• 2003

전복 치패를 부착기질로부터 분리시키는 박리는 전복양식에 있어서 치패의 선별과 밀도 조절을 위해 필수적인 작업이다. 현재 물리적인 방법과 마취제를 이용한 방법이 개발되어 있으나 치패의 손상이 없는 마취제에 의한 박리가 보다 효과적인 것으로 판단되고 있다. 따라서 본 연구는 요소비료($Co(NH_2)_2$)를 마취제로 이용하여 요소비료의 농도와 수온 등 물리적 요인이 까막전복 Haliotis discus의 박리율과 회복률에 미치는 영향을 조사함으로써 경제적이며 효과적인 박리 기술을 개발하고자 하였다. 실험 결과 9∼15%의 요소비료를 해수에 용해시키고 이를 자연 해수와 동일한 수온으로 상승시킨 후 박리를 실시하였더니 3분 이내에 97% 이상이 박리되었으며 치패의 회복률도 역시 높았다. 또한 요소비료 농도와 수온은 높을수록 박리율도 높았으나 치패의 회복률은 낮았다. 결론적으로 본 연구를 통하여 농업용 요소비료를 전복의 박리에 사용할 수 있음을 확인하였으며, 다른 종류의 전복에서도 본 기술의 적용이 가능할 것으로 생각되며, 본 기술은 현재 사용되고 있는 모든 전복 박리방법이나 전복 마취제로 쓰이는 화학약품을 대체할 수 있는 방법으로 판단된다.

• Biomolecules & Therapeutics
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• 제27권2호
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• pp.168-177
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• 2019

Dysregulation of excitatory neurotransmission has been implicated in the pathogenesis of neuropsychiatric disorders. Pharmacological inhibition of N-methyl-D-aspartate (NMDA) receptors is widely used to model neurobehavioral pathologies and underlying mechanisms. There is ample evidence that overstimulation of NMDA-dependent neurotransmission may induce neurobehavioral abnormalities, such as repetitive behaviors and hypersensitization to nociception and cognitive disruption, pharmacological modeling using NMDA has been limited due to the induction of neurotoxicity and blood brain barrier breakdown, especially in young animals. In this study, we examined the effects of intraperitoneal NMDA-administration on nociceptive and repetitive behaviors in ICR mice. Intraperitoneal injection of NMDA induced repetitive grooming and tail biting/licking behaviors in a dose- and age-dependent manner. Nociceptive and repetitive behaviors were more prominent in juvenile mice than adult mice. We did not observe extensive blood brain barrier breakdown or neuronal cell death after peritoneal injection of NMDA, indicating limited neurotoxic effects despite a significant increase in NMDA concentration in the cerebrospinal fluid. These findings suggest that the observed behavioral changes were not mediated by general NMDA toxicity. In the hot plate test, we found that the latency of paw licking and jumping decreased in the NMDA-exposed mice especially in the 75 mg/kg group, suggesting increased nociceptive sensitivity in NMDA-treated animals. Repetitive behaviors and increased pain sensitivity are often comorbid in psychiatric disorders (e.g., autism spectrum disorder). Therefore, the behavioral characteristics of intraperitoneal NMDA-administered mice described herein may be valuable for studying the mechanisms underlying relevant disorders and screening candidate therapeutic molecules.

• Biomolecules & Therapeutics
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• 제25권5호
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• pp.545-552
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• 2017

Increasing concern is being given to the association between risk of cancer and exposure to low-dose bisphenol A (BPA), especially in young-aged population. In this study, we investigated the effects of repeated oral treatment of low to high dose BPA in juvenile Sprague-Dawley rats. Exposing juvenile rats to BPA (0, 0.5, 5, 50, and 250 mg/kg oral gavage) from post-natal day 9 for 90 days resulted in higher food intakes and increased body weights in biphasic dose-effect relationship. Male mammary glands were atrophied at high dose, which coincided with sexual pre-maturation of females. Notably, proliferative changes with altered cell foci and focal inflammation were observed around bile ducts in the liver of all BPA-dosed groups in males, which achieved statistical significance from 0.5 mg/kg (ANOVA, Dunnett's test, p<0.05). Toxicokinetic analysis revealed that systemic exposure to BPA was greater at early age (e.g., 210-fold in $C_{max}$, and 26-fold in AUC at 50 mg/kg in male on day 1 over day 90) and in females (e.g., 4-fold in $C_{max}$ and 1.6-fold in AUC at 50 mg/kg vs. male on day 1), which might have stemmed from either age- or gender-dependent differences in metabolic capacity. These results may serve as evidence for the association between risk of cancer and exposure to low-dose BPA, especially in young children, as well as for varying toxicity of xenobiotics in different age and gender groups.

• 한국양식학회지
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• 제11권4호
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• pp.429-435
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• 1998

조피볼락 초기 사육시 발생하는 대량 폐사 원인의 하나로 수질악화를 들 수가 있다. 수질악화의 주요원인이 되는 어류의 주요대사물인 암모니아에 대한 조피볼락의 내성을 참돔과 비교, 분석하였다. 사육수조 내에 통기를 시키지 않을 경우 산소 부족에서 오는 스트레스로 큰 어체가 작은 어체에 비해 암모니아 독성에 대한 내성이 강한 것으로 나타났다. 조피볼락의 경우, 용존산소량이 높을 때 (통기를 시킬 때), 6 시간이나 96 시간에서의 $NH_45^+$의 반수치사농도가 용존산소량이 낮을 때 (통기를 시키지 않을 때)보다 높아서 수중의 용존산소량이 암모니아 독성을 완화시킨다는 것을 보였다. 또한, 조피볼락과 참돔의 96 시간에서의 $NH_4^+$ 와 비이온화된 $NH_3$ 의 반수치사농도 결과를 비교해 볼 때, 조피볼락은 참돔에 비해 암모니아에 대한 내성이 약한 것으로 나타났다.

• 한국응용곤충학회지
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• 제31권3호
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• pp.289-303
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• 1992

Investigation of the environmental impact of widespread pesticide use has revealed a virtue/vice relationship. Although many pesticides perform their function and disappear without harm to the environment, others persist beyond their useful purpose and cause direct of indirect hazard to man, domestic animals and wildlife. Concurrently, many pests have rapidly adjusted to chemical control practices through changes in behavior that avoid exposure to pesticides of throuth genetic selection for populations resistant to the toxicants. The prospect of losing control over insect herbivores and desease vectors and returning to the days of global hunger and disease is unthinkable. Fortunately, from basic studies of insect and plant biology many opportunities for the development of safe, selective and environmentally pacific strategies for insect pest management are being realized.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.295-296
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• 2001

Dietary lipids are important sources of energy and of essential fatty acids (EFA). Providing desired amounts of EFA is necessary for the normal growth and survival of juvenille fish. EFA requirements of fish are affected by fish species, water temperature and salinity, and different from those of terrestrial animals (Castell 1979). EFA affect the fluidity and permeability of membranes, enzymes activity and are known as the precursors of the eicosanoids. (omitted)