• 한국양식학회지
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• 제17권4호
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• pp.246-250
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• 2004

Survival of 12.7 g (average body weight) Litopenaeus vannamei was examined at temperatures of 14, 16, 18, 28, 32, 34 and 36$^{\circ}C$ and salinities of l0, 20, 30 and 40 ppt after 7 days. Hemolymph osmolality was measured at 12 combinations of salinities (l0, 20, 30 and 40 ppt) and temperature levels (18, 28 and 34$^{\circ}C$) after 14 days. The results show that the species have their best survival between temperatures of 18 and 3$0^{\circ}C$ and salinity above 20 ppt. Hemolymph osmolality increased with increased salinity at all temperatures tested. The isosmotic point calculated from the linear relationship between hemolymph osmolality and medium osmolality and recorded as 826, 809 and 1,117 mOsm/kg which is equivalent to 29.4, 28.8 and 40.2 ppt at 18, 28 and 34$^{\circ}C$, respectively. The slopes obtained from the relationship between hemolymph osmolality and medium osmolality were 0.314, 0.276 and 0.541 for L. vannamei at 18, 28 and 34$^{\circ}C$, respectively, suggesting that the shrimp at 34$^{\circ}C$ regulated osmotic concentration much worse than those at 18 and 28$^{\circ}C$. This result also indicated that L. vannamei living at 34$^{\circ}C$, showed more fluctuation in hemolymph osmolality than those at 18 and 28$^{\circ}C$.

• 한국해양생명과학회지
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• 제7권2호
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• pp.213-220
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• 2022

본 연구는 저염분 상태에서 수온 및 사육밀도와 같은 환경요인이 흰다리새우(Litopenaeus vannamei)의 성장에 미치는 영향을 조사하기 위하여 수행하였다. 연구 결과, 흰다리새우는 저염분 상태에서 전반적으로 수온이 높을수록 생존율이 높게 나타났고, 사육밀도가 낮을수록 생존율이 높아졌다. 사료효율에 관한 연구에서는 수온이 높을수록 증체량(WG)이 증가하였고, 사육밀도가 증가할수록 증체량은 감소하였다. 수온이 높을수록(수온 31℃) 성장 속도가 빨랐다. 또한 사육밀도에 따른 성장도의 평가에서도 사육밀도가 낮은 상태에서 성장 속도가 빨라지는 것을 확인하였다. 본 연구 결과를 흰다리새우의 최적 성장을 위한 적정 사육밀도 및 사육수온의 결정에 유용하게 적용되리라 사료된다.

• 한국어병학회지
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• 제32권2호
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• pp.123-127
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• 2019

In this study, white spots appearing in carapace of imported white leg shrimp Litopenaeus vannamei were observed by macroscopic and microscopic examination. White spots due to white spot disease showed two types, white spots with a regular circular shape ranging from 0.4 mm to 1.7 mm and white spots with an irregular shape ranging from 0.05 mm to 2 mm. White spots due to other causes showed four types that appeared as crystalized materials in range of 100 ㎛ around the tegumental gland, as polygonal inorganic deposits ranging from 58 ㎛ to 188 ㎛, as Linear inorganic deposits ranging from 0.8 mm to 9 mm, as brownish spots ranging from 0.1 mm to 0.4 mm, and brownish spots containing melanin ranging from 0.1 mm to 2 mm. As a result, white spots occurred in imported white leg shrimp Litopenaeus vannamei were divide two type, due to white spot disease or other causes, for quarantine works.

• 한국어병학회지
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• 제36권2호
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• pp.361-368
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• 2023

Juveniles of the white leg shrimp Litopenaeus vannamei (Weight 0.18±0.08 g) were exposed to nitrite-N at 0, 25, 50, 100, 200 and 400 mg/L for 72 hours, and the lethal concentration, heamolymph and genes regulation were evaluated. The lethal concentration 50 (LC₅₀) of L. vannamei exposed to nitrite-N was 141.2 mg/L at 25℃ and 33 psu. In Total protein, total cholesterol, and BUN in heamolymph temporarily increased after the start of the experiment and then stabilized, but glucose, an indicator of stress, decreased over time in the entire experimental group, and creatines, an indicator of tissue damage, decreased with nitrite concentration until the first 12 hours. The genes of immune-related showed that masquerade-like serine proteinase(Mas) increased at 50 and 400 ppm for 24 hours, and then gradually decreased depending on concentration. In the case of prophenoloxidase, it was highest at 400 ppm for 40 hours, and other genes(Ras-related nuclear protein, Masquerade-like serine proteinase, proPO-activating enzyme) showed a response for 48 hours and then gradually decreased. The results of this study indicate that exposure to nitrite can affect the survival and hematological physiology of L. vannamei.

• 한국어병학회지
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• 제33권1호
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• pp.71-75
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• 2020

A survey was conducted to investigate viral infections in 184 whiteleg shrimp (Litopenaeus vannamei) collected from nine farms and one wholesale fish vendor during 2018 and 2019. Gill and abdominal muscle of shrimp were tested for the presence of five viruses, viz. infectious hypodermal and haematopoietic necrosis virus, taura syndrome virus, infectious myonecrosis virus, yellow head virus genotype 1, and covert mortality nodavirus by reverse transcription-polymerase chain reaction (RT-PCR) and PCR. These viruses were not detected in any of 184 samples, screened under the study.

• 미생물학회지
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• 제49권3호
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• pp.237-244
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• 2013

16S rRNA 유전자를 대상으로 454 파이로서열 분석법을 이용하여 해삼(Apostichopus japonicus)과 새우(Litopenaeus vannamei)의 장내 세균의 다양성을 분석하였다. 해삼의 경우, 대부분의 서열은 두 개의 속과 연관성이 있는 것으로 나타났다. 하나는 Fusobacteria 문의 Propionigenium 속이며, 다른 하나는 Bacteroidetes 문의 Flavobacteriaceae 과에 속하는 미분류 속이었다. 새우는 해삼에 비해 다양한 속들을 포함하고 있었으며 Lactococcus, Leuconostoc, Prochlorococcus, Vibrio 속들과 Flavobacteriaceae, Rhodobacteraceae, Desulfobulbaceae, Helicobacteraceae 과와 Mycoplasmatales 목에 속하는 미분류 속들을 포함하고 있었다. 해삼과 새우의 속들의 절반 이상이 환경에서 비배양적으로 얻어진 서열만 존재하는 미분류된 속인 것으로 확인되었다. 대용량 454 파이로서열 분석법을 통하여 해삼과 새우의 장내 세균의 다양성을 밝힐 수 있었으며, 그 결과 해삼과 새우는 아직까지 밝혀지지 않는 새로운 미생물을 많이 포함하고 있는 것을 알 수 있었다.

• 한국어병학회지
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• 제33권1호
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• pp.45-53
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• 2020

Doxycycline is a semi-synthetic broad-spectrum antibiotic, and it has been used to get rid of bacteria in animals and humans. The use of antibiotics has greatly contributed to the aquaculture production although its misuse sometimes presents public health problems. This study was performed to investigate the toxic effects of doxycycline on whiteleg shrimp (Litopenaeus vannamei) administered for possible infection treatments. The shrimp were allocated into four groups and doxycycline was fed three times a day for 7 days at 0, 20, 50 and 100 mg/kg to each group. After 24 hr following the 7-day treatment, hemolymph and hepatopancreas were used for blood and biochemical analysis: Total hemocyte counts, Total protein, Total cholesterol, Gluscose, Glutamic pyruvic transaminase, Glutamic oxaloacetic transaminase, Glutathione peroxidase, Superoxide dismutase, Glutathione-s-transferases, Total antioxidant capacity colorimetric and Acid phosphatase. In addition, histopathological examination was performed on the hepatopancreas and muscle. It was observed that body weight gain was significantly retarded in 100 mg/kg doxycycline group. Doxycycline was found to induce biochemical or functional disorders at 100 mg/kg as observed many of the blood and biochemical parameters were significantly reduced. In conclusion, it was judged that there will be no major toxicity problems with doxycycline when used for shrimp aquaculture at regular doses.

• 한국수산과학회지
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• 제45권6호
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• pp.659-665
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• 2012

A 4-week feeding experiment was conducted with juvenile white shrimp Litopenaeus vannamei to compare the growth of shrimp fed different protein sources: fish meal (FM) and soybean meal (SM). By the end of the experiment, the shrimp grew to $4.50{\pm}0.82$ g (FM) and $4.73{\pm}0.95$ g (SM). The food and protein conversion rates were significant (P<0.05), while other factors did not differ significantly. The survival rate of shrimp fed FM and SM was $96.44{\pm}2.04%$ and $97.33{\pm}1.89%$, respectively. The proximate compositions of the entire body and edible part of the shrimp were similar between FM and SM, except for crude protein. The total amino acid levels were slightly lower in SM than FM, but the difference was not significant. During the experiment, the total ammonia, nitrate, and nitrite concentrations increased continuously in both groups and were slightly higher in SM than FM. In conclusion, soybean meal as a substitute for fish meal results in satisfactory growth and survival of white shrimp.

• 한국환경과학회지
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• 제28권1호
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• pp.1-6
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• 2019

Ptecticus tenebriferwas incorporated to partially or totally replace the diets of juvenile white shrimp (Litopenaeus vannamei). Experimental groups of shrimp with an average initial body weight of $0.014{\pm}0.001g$ were fed each of the 5 diets formulated to include 0, 25, 50, 75, and 100% (C, T25, T50, T75, and T100, respectively) of Ptecticus tenebriferpowder substituted for commercial feed. After eight weeks of feeding trials, juvenile shrimp fed with diets T25 and T50 showed higher live weight gain ($2.298{\pm}0.405$ and $2.539{\pm}0.406$, respectively), and a better feed conversion ratio ($1.389{\pm}0.246$ and $1.536{\pm}0.246$, respectively) compared to those of shrimp fed a control diet. Survival rate was 98% in all experimental groups except for the T75 group ($66.67{\pm}57.73%$ survival). The levels of immune markers such as beta-glucan binding protein, prophenoloxidase, and crustin associated with the cellular and humoral immunity of shrimp were found to be higher in 25% and 50% commercial feed replacement groups. A reduction in total nitrogen, nitrite nitrogen, and ammonia levels was greater in T25 and T50 rather than in T75 and T100. These results clearly indicate that replacement of feed with 25 to 50% Ptecticus tenebriferpowder in juvenile white shrimp diet was optimal in promoting the growth performance of shrimp without any adverse effects.

• Fisheries and Aquatic Sciences
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• 제20권7호
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• pp.15.1-15.7
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• 2017

An 8-week feeding trial was conducted to study the effect of dietary supplementation of a biofloc powder on growth performance and non-specific immune response of Litopenaeus vannamei. Seven experimental diets were prepared with supplementation of graded levels of dried biofloc powder by 0, 0.5, 1.0, 2.0, 4.0, 6.0, and 8.0% (designated as Con, BF0.5, BF1, BF2, BF4, BF6, and BF8, respectively). Triplicate groups of shrimp ($1.01{\pm}0.01g$) were hand-fed with one of the diets four times a day. At the end of the feeding trial, significantly (P<0.05) higher growth performance and feed utilization were obtained in BF4 groups compared to those fed the Con diet. The innate immunity of shrimp was improved by the dietary supplementation of biofloc. Dietary inclusion of biofloc at the level of 4.0% significantly increased disease resistance of shrimp against Vibrio harveyi. The results indicate that biofloc might be used as a dietary supplement for growth performance, innate immunity and disease resistance of Pacific white shrimp.