• 한국수산과학회지
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• 제29권1호
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• pp.1-8
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• 1996

본 실험은 대하의 효율적인 종묘생산을 위하여 수온과 염분에 따른 수정난의 부화율에 관한 실험으로서 다음과 같은 결과를 얻었다. 대하수정난의 부화에 미치는 수온의 영향을 조사한 결과, $24^{\circ}C$에서 $95.5\%$의 가장 높은 부화율을 보였다. $20^{\circ}C$에서 $24^{\circ}C$까지는 수온이 올라갈수록 부화율은 높게 나타났으며, $26^{\circ}C$이상부터는 수온이 올라갈수록 부화율은 급격히 낮아져, $30^{\circ}C$에서는 전혀 부화가 되지 않았다. 염분의 영향을 조사한 결과, $31\%_{\circ}$에서 $95.5\%$의 가장 높은 부화율을 보였다. $20\%_{\circ}$, 부터 $31\%_{\circ}$까지는 염분이 상승할수록 부화율은 증가하였고, $33\%_{\circ}$, 부터는 염분이 상승할수록 부화율은 낮아져 $40\%_{\circ}$, 에서는 $25.5\%$%로 급격히 감소하였다. 수온 $24^{\circ}C$에서의 부화속도는 다른 수온구에서보다 가장 빨랐고 특히 염분 $31\%_{\circ}$의 실험구에서는 18시간 만에 $30.5\%$, 48시간만에 $95.5\%$가 부화되어 가장 빠른 부화속도를 보였다. 대하수정난의 부화를 위한 최적 수온은 비교적 협온성이라고 할수있다. 또 최적수온인 $24^{\circ}C$에서도 자연해수의 염분구 $(33\~35\%_{\circ})$보다 다소 낮은 $30\~31\%_{\circ}$,에서는 약 $20\%$정도 더 높은 부화율이 유도되었다. 이러한 결과를 볼 때 대하수정난 부화를 위한 최적염분 역시 협염성이며 특히 수온이 높을 때 염분이 부화율에 미치는 영향은 매우 민감하였다.

• 한국수산과학회지
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• 제44권6호
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• pp.665-670
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• 2011

The rotifer Brachionus plicatilis is one of the most important food organisms in aquaculture. The resting eggs produced by mictic female rotifers are easily stored and hatched, making them useful as the starter for the mass culture of rotifers in marine larval culture. This study examined the optimum preservation method for resting eggs to ensure a high hatching rate. To produce resting eggs, the marine rotifer B. plicatilis was cultured with Nannochloris oculata (KMMCC 16). The resting eggs were harvested and cryopreserved using 5% and 10% methanol (MeOH), dimethylsulfoxide (DMSO), and glycerol as cryoprotectant agents (CPAs). The cryopreservation comprised slow or rapid freezing and the resting eggs were stored for one month in liquid nitrogen ($-196^{\circ}C$). The resting eggs were also dried at different temperatures (30, 40, and $50^{\circ}C$) and for different times (1, 2, and 3 h). In general, the hatching rates of the resting eggs preserved with CPA were higher than those without CPA and the slow freezing method was better than the rapid freezing method. However, the optimum CPA concentration for the hatching rate of the resting eggs varied with the freezing method and kind of CPA, and the CPA also affected the viability of the resting eggs. Dried resting eggs had a high, rapid hatching rate over 80%. The moisture content of the resting eggs cryopreserved in liquid nitrogen affected the hatching rate. Drying at $30^{\circ}C$ for 1 hour resulted in a high hatching rate of the resting eggs. In conclusion, drying at $30^{\circ}C$ for 1 hour and preservation in liquid nitrogen with the slow freezing method, without CPA, is recommended for a high hatching rate (ca. 95%) of rotifer resting eggs.

• Fisheries and Aquatic Sciences
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• 제14권4호
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• pp.417-420
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• 2011

In this experiment, we examined the survival, fertilization, hatching times, and hatching rates of Far Eastern catfish Silurus asotus at pH ranging from 2 to 13 under laboratory conditions. Eggs could be fertilized at pH 3-12. In a hatching experiment, mortality was first observed at pH 13, when all fertilized eggs died within 8 min, followed by pH 2 (30 min), pH 12 (60 min), pH 3 (4 h), and pH 11 (5 h). Hatching only occurred at pH 4-10, with the highest hatching rate at pH 7 (52%) and the lowest at pH 10 (24%). Hatching rates in acid solutions were higher than in alkaline solutions, although the difference was not significant. Hatching was first observed at pH 10, beginning 27 h after fertilization and ending at the 31 h. A clear difference was observed between hatching times, ranging from 31 to 64 h and increasing in order with descending pH.

• Fisheries and Aquatic Sciences
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• 제15권2호
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• pp.177-181
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• 2012

To understand the effects of lower pH levels due to elevated $CO_2$ and salinity, we designed and constructed a pH-control system that included automatic $CO_2$ infusion and measured the hatching rate of a crustacean model species, Artemia franciscana. The pH-control system was cost-effective and capable of performing animal tests in which pH fluctuated around $8.0{\pm}0.1$, with the temperature around $27{\pm}0.5^{\circ}C$. Hatching rate was observed under four different pH levels (7.0, 7.3, 7.6, and untreated control) combined with three salinity ranges (15, 25, and 35 ppt). The results demonstrated that lower pH levels led to decreased hatching rates regardless of salinity, and the minimum hatching rate was detected at pH 7.0 compared to the control (pH $8.0{\pm}0.1$), supporting the idea that OA has adverse effects on hatching rates and increases the risk of juveniles being introduced in the ecosystem. In contrast, salinity changes exhibited no synergistic effects with pH and had independent effects.

• 한국수산과학회지
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• 제53권4호
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• pp.486-491
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• 2020

This study was investigated the survival and hatching rate of fertilized eggs in olive flounder Paralichthys olivaceus at water temperature, salinity, duration of transport and different stock densities during commercial transport. The observed optimal temperature during transport was 17.5℃ similar to the natural environmental conditions. The proper salinity was observed to be at 33 psu (practical salinity unit) in both surviving and hatching rate. In terms of the duration of transport, there were no differences until 12 hours between survival and hatching rate, but shorter time of transport would be better. With the best conditions during transport, 20,000 eggs/L were handled in both survival and hatching rate. These results can be essential in the production and transport of healthy olive flounder seeds.

• 한국양식학회지
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• 제12권1호
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• pp.25-30
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• 1999

피라미의 종묘를 생산하기 위하여인공부화, 먹이, 성장을 조사하였다. 난황이 갓 흡수된 개체는 전장이 7.6~8.2mm(평균 7.97mm) 이었으며, 부화 후 3일만에 부상하였다. 부상 후 소형 물벼룩, 윤충류, 알테미아를 섭취하였으며, 초기용 인공 분말사료도 섭취하였다. $20~32^{\circ}C$의 온도조건에서 부화시험을 한 결과 부화율은 $26^{\circ}C$에서 가장 높았으며, 47시간이 소요되었다. 부화기의 형태 중에서는 부화병에서 부화율이 89%로 가장 높았으며, 그물상자 및 Californian 부화기에서도 부화율 80% 이상으로 높았다. 부화 후 50일간 사육 한 결과 30.0mm(25.6~32.0mm)로 성장하였다. 온도가 높을수록 자어의 성장이 빨랐는데, 특히 $26^{\circ}C$ 이상에서 성장이 양호하였다. 그러나, 생존율은 $32^{\circ}C$에서 가장 낮았다. 부화직후부터 배합사료만으로서 사육이 가능하였으며 알테미아나 잉어용 사료에 비해서 넙치 및 조피볼락용 사료에서 성장이 양호하였다.

• Ocean and Polar Research
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• 제35권3호
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• pp.239-247
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• 2013

Digital image processing is a process to analyze a large volume of information on digital images. In this study, Artemia hatching rate was measured by automatically classifying and counting cysts and larvae based on color imaging data from cyst hatching experiments using an image processing technique. The Artemia hatching rate estimation consists of a series of processes; a step to convert the scanned image data to a binary image data, a process to detect objects and to extract their shape information in the converted image data, an analysis step to choose an optimal discriminant function, and a step to recognize and classify the objects using the function. The function to classify Artemia cysts and larvae is optimally estimated based on the classification performance using the areas and the plan-form factors of the detected objects. The hatching rate using the image data obtained under the different experimental conditions was estimated in the range of 34-48%. It was shown that the maximum difference is about 19.7% and the average root-mean squared difference is about 10.9% as the difference between the results using an automatic counting (this study) and a manual counting were compared. This technique can be applied to biological specimen analysis using similar imaging information.

• 한국양식학회지
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• 제9권4호
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• pp.339-344
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• 1996

한국산 rotifer, Brachionus plicatilis 내구란의 부화에 미치는 온도($24\~36^{\circ}C$)와 염분($5{\~}30$ ppt)의 영향을 조사하였다. 가장 높은 내구란의 부화율은 $28^{\circ}C$, 15 ppt에서 $85.7{\%}$로 나타났다. 온도 $32^{\circ}C(42.6\~60.5\%)$와 $36^{\circ}C(52.0\~61.4\%)$에서는 염분과 수온에 따른 부화율은 유의적인 차이를 보이지 않았다. 부화시간은 온도가 높을수록 짧게 나타났다. $5^{\circ}C$ 암흑상태로 내구란을 보존할 경우 2일 동안 일시적으로 부화하였다. 그러나 $28^{\circ}C$ 내구란을 보존한 경우, 14일 동안 산발적으로 부화하였다. 또한 부화율은 $28^{\circ}C(58.1\%)$가 $5^{\circ}C(40.2\%)$ 보다 높게 나타났다. 내구란의 건조온도가 시간에 따른 부화율은 $30^{\circ}C$에서 1시간동안 건조한 내구란이 $46.4{\%}$로 가장 높은 부화율을 보였다.

• 한국어류학회지
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• 제22권3호
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• pp.195-200
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• 2010

대구 부화자어 대량방류를 위한 기초 연구로서 대용량 부화기를 이용한 대구 수정란 부화 방법을 검토하였다. 기존의 용량 15L와 시험용 42L인 부화기에 수정란을 수용한 결과 9일째 생존율이 48.3%와 50.4%로 나타나 부화기 용량차이에 따른 생존율은 유의한 차이가 없었다. 제작한 실험 부화기와 기존의 원형수조에서 수정란 생존율을 비교한 결과 40.0~71.2%로 부화기에서 높아 대구 수정란 부화에 실험 부화기가 효율적인 것으로 사료된다. 또한 42 L 부화기에 수정란 5,000 mL (약 825만 개)를 수용하여도 높은 부화율을 유지하였다. 결과적으로 대구 수정란 부화 시 대용량 부화기를 이용할 경우, 고밀도로 수용하여도 높은 수정란 생존율 유지가 가능하고 사육 공간과 인력 및 경비를 절감할 수 있을 것으로 생각된다. 또한 원형수조에 비하여 사육수 절약 (6,700 mL/min)과 수정란 그룹별 수용이 가능하다는 장점이 있다.

• 한국가금학회지
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• 제27권3호
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• pp.181-187
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• 2000

This work was designed to investigate the performances of broiler breeder hens upon the addition were vitamin and mineral supplements in feeds. Animals were divided into for feed groups such as control, T$_1$,T$_2$and T$_3$, and each treatment has four replications. All broiler breeder hens were housed individually, and were fed with identical iso-metaboilic energy and iso-protein, except for vitamins and minerals. Different sources and levels of vitamins and minerals were added to the basic feeds according to the treatments. At the end of the experiments, general laying rate(hen days), average egg weight, hatching egg laying rate(Hen day) every day. Hatching egg weight, sterility, embryo mortality, hatching rate and chick weight were examined. Although, early laying rate in all treatment groups were reduced during cold term management, general egg laying rate was increased only T$_3$group which was contanining vitamin C. However, similar results were obtained in the rates of general and hatching egg laying. General egg laying rate were somewhat higher of Control, T$_2$and T$_3$ groups than that of T$_1$group. In addition, the laying rates of general and hatching eggs slightly improved in the T$_3$group rather than those of Control group. Egg weight was reduced with the increasing of laying rate, showing the highest in the T$_3$group. The laying rate showed significantly lower value than those of any other groups. Egg weight was about 65g in T$_3$group. The results of hatching performance for production ability of Broiler breeder hens were fed experimental diet, although the rates of non-hatched and hatched eggs increased in order of Control, T$_1$T$_2$and T$_3$groups. However, the rate of embryo mortality was declined in order Control, T$_1$T$_2$and T$_3$groups.