• 한국어병학회지
• /
• 제33권1호
• /
• pp.23-34
• /
• 2020

In recent years, global warming is causing dramatic environmental changes and deterioration, such as hypoxia, leading to reduced survival rate and growth performance of farmed aquatic animals. Hence, understanding systemic immuno-physiological changes in fish under environmental stress might be important to maximize aquaculture production. In this study, we investigated physiological changes in rainbow trout exposed to hypoxic stress by monitoring changes in blood chemistry, leukocyte population, and expression levels of related cytokine genes. Hematological and serological factors were evaluated in blood obtained from rainbow trout sampled at a dissolved level of 4.6 mg O₂ L^-1 and 2.1 mg O₂ L^-1. Blood and head kidney tissue obtained at each sampling time point were used to determine erythrocyte size, leukocyte population, and cytokine gene expression. The level of LDH and GPT in fish under progressive hypoxia were significantly increased in plasma. Likewise, the (Granulocyte + Macrophage)/lymphocyte ratio (%) of fish exposed to hypoxia was significantly lower than that in fish in the control group. Such changes might be due to the rapid movement of lymphocytes in fish exposed to acute hypoxia. In this study, significant up-regulation in expression levels of IL-1β and IL-6 gene appeared to be involved in the redistribution of leukocytes in rainbow trout. This is the first study to demonstrate the involvement of cytokines in leukocyte trafficking in fish exposed to hypoxia. It will help us understand systemic physiological changes and mechanisms involved in teleost under hypoxic stress.

• 한국어류학회지
• /
• 제11권2호
• /
• pp.163-171
• /
• 1999

열목어를 비롯한 산천어, 시마연어, 연어, 무지개송어 등 우리나라 연어아과 어류의 미토콘드리아 DNA control region의 염기서열 조성 및 구조적 변이를 비교 분석하였다. 열목어속의 열목어는 연어속의 종들과 다수의 염기치환 및 삽입/결실에 의해 뚜렷하게 구별되었으며, 연어속어종간에는 5.42~16.49%의 염기치환율을 나타내었다. 한편, 산천어와 시마연어의 염기서열은 100% 일치하였으며, 무지개송어와 알비노사이에는 단지 3개의 전이만이 관찰되었다. 3' 말단쪽에 77~96 bp의 반복서열이 종렬배열되어 종간에 뚜렷한 길이변이를 나타내었는데, 특히 열목어에서는 특징적으로 81 bp 영역이 2 copy로 배열되어 있었다. 각각의 반복서열상의 염기조성에 있어서도 종간 특이성을 나타내었으며, 이러한 control region에서의 염기변이는 연어아과 어류의 표지인자로써 유용하게 사용되어질 수 있으리라 사료되어진다.

• The Korean Journal of Ecology
• /
• 제26권6호
• /
• pp.297-305
• /
• 2003

Fish fauna of mountain streams in the Jirisan National Park area of S. Korea (total area: 440.45 $\textrm{km}^2$, height: 1,915 m) was investigated at 33 sites from May 1997 to September 1999. A total of 4,670 individuals of fishes were collected and classified into 30 species and 12 families. Zacco temmincki (relative abundance (RA), 63.9%) was found to be the most abundant inhabitant. Subdominant species were Pungtungia hem (RA 6.2%), Zacco platypus (RA 6.1 %) and Coreoleusiscus splendidus (RA 4.8%). Among the total species, 13 species were identified as the Korean endemic species (7 families, 17.2% of 802 individuals). Dominant Korean endemic species was C. splendidus (relative abundance endemics (RAE), 27.8%). Superiors were Coreoperca heizi (RAE 21.8%) and Liobagrus mediadiposalis (RAE 19.8%). One exotic species (Oncorhynchus mykiss, a site and 5 ind.) and translated species (Hypmesus niponensis, two sites and 174 ind.) were collected in this survey. The proportion of Korean endemic species in the park (43.3%) was higher than the average of Korean Peninsular (25.9%). From this study, we conclude that the Jirisan National Park area in Korea would be very important for fish diversity and conservation, especially for the Korean endemic and endangered species.

• 한국양식학회지
• /
• 제5권1호
• /
• pp.1-7
• /
• 1992

어분의 대체원료로써 대두당의 유효성을 개선하기 위하여, 사료용 대두정 (H-SBM)과 식품용 미처리 대두당(R-SBM)을 Ex 처리하여, 무지개송어에 있어서 사료중 대두박의 단백질 및 탄수화물의 소화율을 측정하였으며, 트립신 저해 인자 (TI)의 활성과 단백질 소화율과의 관계에 대해서 검토하였다. 그 결과 H-SBM 및 R-SBM 모두 Ex 처리함으로써 단백질의 소화율이 $95{\%}$까지 개선되었다. 한편, R-SBM의 탄수화물의 소화율은 Ex 처리에 의해 향상되었으나, H-SBM는 개선되지 않았다. 또 Ex 처리에 의해 대두박중의 TI 활성은 대두분 소실되었으며, R-SBM에는 TI의 소실화에 의해 단백질의 소화율이 향상되었으나, 이것이 Ex 처리에 의한 TI의 활성의 소실에 의한 것인지는 본 실험 조건 하에서는 명백히 할 수 없었으며, 금후 구체적인 검토를 필요로 한다.

• IMMUNE NETWORK
• /
• 제8권3호
• /
• pp.67-74
• /
• 2008

Background: The effects of the dietary administration of two heat-inactivated whole bacteria from the Vibrionaceae family, singly or combined, on innate immune response of the rainbow trout were studied. The two bacteria (Pdp11 and 51M6), which were obtained from the skin of rainbow trout, showed in vitro characteristics that suggested they could be considered as potential fish probiotics. Methods: The fish were fed four different diets: control (non-supplemented), or diets supplemented with heat-inactivated bacteria at $10^8$ cfu/g Pdp11, $10^8$ cfu/g 51M6 or with $0.5{\times}10^8$ cfu/g Pdp11 plus $0.5{\times}10^8$ cfu/g 51M6 for 4 weeks. Six fish were sampled at weeks 1, 2, 3 and 4, and then the main humoral (natural haemolytic complement activity and serum peroxidase content) and cellular innate immune responses (leucocyte peroxidase content, phagocytosis, respiratory burst and cytotoxicity) were evaluated. Results: The serum peroxidase content and the natural haemolytic complement activity increased with time, reaching the highest values in the third and fourth weeks of feeding, respectively. The phagocytic ability of specimens fed the mixture of the two inactivated bacteria was significantly higher than in the controls after 2 and 3 weeks of treatment. The same activity increased significantly in rainbow trout fed the Pdp11 diet for 2 weeks or the 51M6 diet for 3 weeks. Respiratory burst activity was unaffected by all the experimental diets at all times assayed. Cytotoxic activity had significantly increased after 3 weeks in fish fed the 51M6 diet. Conclusion: Our results demonstrated the usefulness of incorporating inactivated probiotic bacteria into fish diets.

• Fisheries and Aquatic Sciences
• /
• 제14권4호
• /
• pp.379-388
• /
• 2011

The mechanism by which gonadotropin-releasing hormone (GnRH) and dopamine (DA) control gonadotropin (GTH) release was studied in male and female rainbow trout using cultured pituitary cells obtained at different reproductive stages. The mechanisms of follicle-stimulating hormone (FSH) release by GnRH and DA could not be determined yet. However, basal and salmon-type GnRH (sGnRH)- or chicken-II-type GnRH (cGnRH-II)- induced luteinizing hormone (LH) release increased with gonadal maturation in both sexes. LH release activity was higher after sGnRH stimulation than cGnRH-II stimulation at maturing stages in both sexes. The GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) suppressed LH release by sGnRH stimulation in a dose-dependent manner, although the effect was weak in maturing fish. The role of DA as a GTH-release inhibitory factor differs during the reproductive cycle: the inhibition of sGnRH-stimulated LH release by DA was stronger in immature fish than in maturing, ovulating, or spermiated fish. DA did not completely inhibit sGnRH-stimulated LH release, and DA alone did not alter basal LH release. Relatively high doses ($10^{-6}$ or $10^{-5}M$) of domperidone (DOM, a DA D2 antagonist) increased LH release, which did not change with reproductive stage in either sex. The potency of DOM to enhance sGnRH-stimulated LH release was higher in maturing and ovulated fish than in immature fish. These data suggest that LH release from the pituitary gland is controlled by dual neuroendocrine mechanisms by GnRH and DA in rainbow trout, as has been reported in other teleosts. The mechanism of control of FSH release, however, remains unknown.

• Preventive Nutrition and Food Science
• /
• 제21권3호
• /
• pp.281-288
• /
• 2016

This study was designed to investigate the effects of dietary astaxanthin levels on growth performance, feed utilization, muscle pigmentation, and antioxidant capacity in juvenile rainbow trout. Four experimental diets were formulated to contain 0, 50, 75, and 100 mg/kg astaxanthin (designed as AX0, AX50, AX75, and AX100). Each diet was fed to triplicate groups of fish (18.5 g/fish) for 10 weeks. Growth performance and muscle composition of fish were not affected by dietary astaxanthin levels. Total carotenoid concentration in the muscle of fish fed the AX50 diet was higher than that of fish fed the AX0 diet, but no significant differences were observed between these fish and those fed the AX75 and AX100 diets. Muscle astaxanthin content increased with increased astaxanthin in the diet. Deposition of astaxanthin in the flesh resulted in a decrease in lightness and an increase in redness and yellowness. The fillets from trout fed the AX75 diet had significantly lower lightness than trout fed the AX50 and AX100 diets. Fish fed the AX50 and AX75 diets showed significantly lower catalase activity than those fed the control diet. Total antioxidant status increased significantly in all astaxanthin supplemented groups when compared to the control group. Superoxide dismutase activity was significantly decreased in fish fed the AX50 diet compared to fish fed the AX0 diet. These findings suggest that while fillet pigmentation increased with increasing dietary astaxanthin concentration, indices of fish antioxidant capacity may not be affected in a dose dependent manner.

• 한국양식학회지
• /
• 제13권1호
• /
• pp.79-85
• /
• 2000

자성 및 웅성스테로이드 호르몬들이 Vg 유전자발현에 영향을 미치는지를 미성숙 무지개송어의 배양간세포 막간을 이용하여 조사하였다. 이미 보고된 송어의 Vg gene의 염기배열을 참고로 Vg cDNA 단편(600 bp)을 증폭시킬 수 있는 primer들을 작성하였다. 이들 primer를 이용하여 증폭된 PCR 산물의 염기배열을 결정하여 송어의 Vg cDNA임을 확인하였고, RT-PCR법을 이용하여 배양간세포 그리고 E$_2$ 및 MT 처리된 송어의 간으로부터 Vg mRNA의 전사량 변화를 조사하였다. 호르몬 처리된 간세포 및 송어의 간에서 추출한 total RNA를 이용하여 RT-PCR법으로 분석한 결과 in vivo, in vitro 실험 모두에서 E$_2$ 또는 MT처리된 간세포 및 송어의 간으로부터 Vg mRNA와 Vg 단백질합성이 유도되었고, 이들의 증가 경향은 처리된 호르몬 농도 및 시간에 의존하고 있음이 밝혀졌다. 또한 progesterone, androsterone 그리고 testosterone 등의 웅성호르몬들도 Vg mRNA의 전사를 유도하고 있다는 것이 시사되었다. 이와 같은 결과로부터E$_2$ 뿐 아니라 웅성스테로이드들도 Vg mRNA의 발현을 유도하고 있음이 송어의 in vivo 또는 in vitro 실험에 의해서 확인되었다.

• Fisheries and Aquatic Sciences
• /
• 제17권1호
• /
• pp.1-11
• /
• 2014

The Kenyan aquaculture sector is broadly categorized into freshwater aquaculture and mariculture. Whereas freshwater aquaculture has recorded significant progress over the last decade, the mariculture sector has yet to be fully exploited. The Kenyan aquaculture industry has seen slow growth for decades until recently, when the government-funded Economic Stimulus Program increased fish farming nationwide. Thus far, the program has facilitated the alleviation of poverty, spurred regional development, and led to increased commercial thinking among Kenyan fish farmers. Indeed, national aquaculture production grew from 1,000 MT/y in 2000 (equivalent to 1% of national fish production) to 12,000 MT/y, representing 7% of the national harvest, in 2010. The production is projected to hit 20,000 MT/y, representing 10% of total production and valued at USD 22.5 million over the next 5 years. The dominant aquaculture systems in Kenya include earthen and lined ponds, dams, and tanks distributed across the country. The most commonly farmed fish species are Nile tilapia Oreochromis niloticus, which accounts for about 75% of production, followed by African catfish Clarias gariepinus, which contributes about 21% of aquaculture production. Other species include common carp Cyprinus carpio, rainbow trout Oncorhynchus mykiss, koi carp Cyprinus carpio carpio, and goldfish Carassius auratus. Recently, Kenyan researchers have begun culturing native fish species such as Labeo victorianus and Labeo cylindricus at the National Aquaculture Research Development and Training Centre in Sagana. Apart from limited knowledge of modern aquaculture technology, the Kenyan aquaculture sector still suffers from an inadequate supply of certified quality seed fish and feed, incomprehensive aquaculture policy, and low funding for research. Glaring opportunities in the Kenyan aquaculture industry include the production of live fish food, e.g., Artemia, daphnia and rotifers, marine fish and shellfish larviculture; seaweed farming; cage culture; integrated fish farming; culture of indigenous fish species; and investment in the fish feed industry.

• Fisheries and Aquatic Sciences
• /
• 제21권11호
• /
• pp.32.1-32.7
• /
• 2018

Trout production is a growing activity in recent years but requires new alternative sources of feed to be sustainable over time. The objective of this research was to determine the apparent digestibility coefficient (ADC) of dry matter (DM), organic matter (OM), crude protein (CP) and digestible energy (DE) of $ka{\tilde{n}}iwa$ (Chenopodium pallidicaule Aellen), kiwicha (Amaranthus caudatus L), quinoa (Chenopodium quinoa Willd), beans (Phaseolus vulgaris L.), sacha inchi, (Plukenetia volubilis L) and jumbo squid (Dosidicus gigas) meal in juvenile rainbow trout. The experimental diets were composed of a 70% basal diet and 30% of any raw materials. The ADC was determined by the indirect method using insoluble ash as a non-digestible marker. Jumbo squid, sacha inchi and quinoa showed the highest values of ADC (%) of DM (84.5, 73.5 and 69.7), OM (89.1, 78.4 and 72.9), CP (93.2, 98.0 and 90.3), and DE (4.57, 4.15 and 2.95 Mcal/kg DM), respectively. The ADC values for $ka{\tilde{n}}iwa$, kiwicha and bean were significantly lower. In conclusion, quinoa meal and jumbo squid meal have an acceptable digestibility but sacha inchi meal is a potential alternative for rainbow trout feeding in the future.