• 한국수산과학회지
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• 제55권6호
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• pp.886-893
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• 2022

This study was conducted to evaluate the effects of dietary silymarin supplementation on the growth performance, feed utilization, innate immunity and antioxidant capacity of Pacific white shrimp Litopenaeus vannamei. Four experimental diets were formulated to contain 0, 0.025, 0.05 and 0.1% silymarin (designated as Con, S0025, S005 and S01, respectively). Triplicate groups of shrimp (initial body weight: 0.70 g) were fed each of the diets for 6 weeks. After the feeding trial, weight gain and specific growth rate were significantly higher in silymarin-supplemented groups compared to Con group. Dietary silymarin significantly enhanced protein efficiency ratio of S01 group and reduced feed conversion ratio of S005 and S01 groups. Phenoloxidase and anti-protease activities were significantly higher in S01 group compared to Con group. Glutathione peroxidase and catalase activities were significantly higher in silymarin-supplemented groups compared to those of Con group. The results of this study indicate that dietary silymarin could improve the growth performance, feed utilization, innate immunity and antioxidant capacity of Pacific white shrimp. The optimum level of silymarin in diet for Pacific white shrimp is suggested to be ≥0.025%.

• 한국수산과학회지
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• 제56권1호
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• pp.133-139
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• 2023

The advantage of biofloc technology (BFT) in aquaculture is in the prevention of pathogenic transmission. In this study, we performed an investigation on viral, bacterial, and microsporidian parasite infections targeting a total of 194 whiteleg shrimp Litopenaeus vannamei reared in seven BFT-farms on the west coast of Korea in 2021. Hepatopancreatic and cuticular epithelium and pereiopods tissues of shrimp were tested for the four pathogens, Enterocytozoon hepatopenaei (EHP), Vibrio parahaemolyticus causing Acute Hepatopancreatic necrosis disease (VP_AHPND), white spot syndrome virus (WSSV), and hepatopancreatic parvovirus (HPV). The microsporidian parasite EHP was detected in the hepatopancreatic tissue of BFT whiteleg shrimp in the Ganghwa region, whereas no other pathogenic bacteria or virus was detected on the shrimp in the seven BFT-farms. As a result of bacterial flora in the rearing water of BFT whiteleg shrimp using DNA microbiome technology, V. chemaguriensis and V. alfacsensis were contained at 0.05% and 0.01%, respectively, but no VP_AHPND was detected. These findings will serve as a basis for supporting safe BFT-aquaculture of whiteleg shrimp.

• 한국식품위생안전성학회지
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• 제32권5호
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• pp.363-370
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• 2017

본 실험에서는 냉동 새우(Litopenaeus vannamei)를 $4^{\circ}C$에서 12일동안 저온 저장하며, 키토산 코팅과 천연보존제의 병행처리(0.05% carvacrol, 0.05% thymol)가 미생물(중온균, 저온균, Pseudomonas spp., $H_2S$ 생성균)의 성장과 새우의 이화학적 특징(총 휘발성 질소화합물, pH) 및 관능적 품질(외관, 냄새, 전반적 수용도)에 미치는 영향을 살펴보았다. 키토산 코팅과 carvacrol 병행 처리, 키토산 코팅과 thymol 병행 처리는 모든 대상 미생물의 성장을 억제하였고 특히 중온균, 저온균, $H_2S$ 생성균의 경우 실험의 마지막 날인 12일째까지 유의적인 항균효과(p < 0.05)를 보였다. 이 처리구들은 총 휘발성 질소화합물과 관능적 특성(외관, 냄새, 전반적 수용도)에서도 12일째까지 유의적인 차이(p < 0.05)를 보였으나 pH에서는 유의적 차이가 없었다. 따라서 키토산 코팅과 carvacrol 병행 처리, 키토산 코팅과 thymol 병행 처리는 새우의 주요 부패 미생물의 성장을 효과적으로 억제하는 것으로 보이며 냉장 새우의 유통기간 연장에 활용할 수 있을 것으로 보여진다.

• 한국양식학회지
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• 제19권1호
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• pp.1-6
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• 2006

흰다리새우 양식기법의 최적화를 위하여 소화기간 동안의 간췌장, 전장 그리고 중장에서의 trypsin의 활성변화를 조사하였다. 체중에 대한 전장, 중장의 무게 그리고 그 무게 합의 비율은 섭취된 먹이의 이동 및 소화과정을 나타내는 지표로서 공급량과 잔류량에 의한 먹이섭취량을 측정하는 것 보다 더 정확한 지표로서 사용 가능하였다. 평균적으로 치대 먹이섭취량은 전장에서 먹이섭취 후 30분 이내에 체중에 0.3%로 나타났다. 또한 30분 이후부터 전장이 비워지기 시작되었으며 중장의 무게가 최대에 이르는 시각은 2시간째였다. $3{\sim}5$시간 후에는 먹이가 배설됨으로 인하여 중장의 체중에 대한 무게비가 감소하였으나 전장에서는 비교적 같은 비율을 유지하였다. 먹이섭취에 의한 trypsin활성변화는 간췌장에서 가장 커서 전장에서의 활성변화에 비하여 약 3배로 나타났다. 소화시간이 지날수록 간췌장에서의 trypsin 활성은 지속적으로 증가하였다. 전장에서의 trypsin 효소의 활성은 중장보다 약 $2{\sim}3$배정도 높았다 먹이섭취 후 2시간이 지났을 때 trypsin 활성은 303 n mol/mg/min였고, 4시간까지 이 활성이 유지($277{\sim}306$ n mol/mg/min)되었으며, 그 후에는 점차 감소하였다. 중장에서는 typsin 활성이 먹이를 섭취하여 한 시간이 지나면서 $65{\pm}29$ (SE) n mol/mg/min로 증가하였다. 그 이후에는 $80{\sim}97$ n mol/mg/min의 범위를 나타내었으며, 5시간이 경과하였을 때 $52{\pm}17$ (SE) n mol/mg/min로 감소하였고 소화관내에 잔류하고 있는 먹이 량은 최대 섭취량의 50%로 나타났다.

• 한국수산과학회지
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• 제43권4호
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• pp.331-339
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• 2010

Shrimp farming is the most important mariculture industry on the west coast of South Korea. However, it has suffered from mass mortality due to viral disease outbreaks and coastal pollution due to water discharge. This study developed an intensive shrimp culture method for outdoor ponds, without water exchange, which minimizes the chance of viral transmission from the environment, reduces coastal pollution by water discharge and enhances shrimp production. A culture trial was conducted in two high-density polyethylene (HDPE)-lined ponds with a $550\;m^2$ surface area. The ponds were stocked with postlarvae of Litopenaeus vannamei, the major farmed shrimp species in Korea, on July 10, 2007, and cultured for 90 days with no water exchange. The stocking density of the postlarvae (B.W. 0.0015 g) was $272\;ind./m^2$, which is eight times higher than in traditional pond culture in Korea. At harvest, the total production of ponds 1 and 2 was 1,362kg ($2.48\;kg/m^2$) and 1,282 kg ($2.33\;kg/m^2$), respectively. This is 20~22 times higher than the mean farmed shrimp production ($0.112\;kg/m^2$) in Korea and about eight times higher than in traditional ponds with a good harvest. Although there was no water exchange throughout the culture period, the mean concentrations of unionized ammonia and nitrite-nitrogen were as low as 0.038 and 6.0 mg/L, respectively. The feed conversion rate (FCR) was 1.38, which is 20~45% lower than that of traditional pond cultures. The high efficiency of the diet in this study is thought to be due to a well-managed feeding strategy and well-developed bioflocs used as diet additions for the shrimp. The final body weight of the shrimp at harvest was low (12.2~12.5 g), compared with that of traditional pond culture. This may have resulted from the combination of a short culture period, high density of shrimp, and low temperature. This study suggests that a super-intensive shrimp pond culture method using biofloc technology with no water exchange can minimize viral transmission via water exchange, reduce coastal pollution, and enhance shrimp production.

• 환경생물
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• 제36권3호
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• pp.377-384
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• 2018

저염분 순치기간에 먹이를 섭취함으로서 얻을 수 있는 초기 유생의 생리적 변화는 다음과 같이 요약할 수 있다. 하루 동안의 순치기간에 염분농도에 따른 유생의 생존율은 차이를 보였지만 각 염분구간별 먹이섭취 유무에 따른 생존효과는 유사하였다. 그러나 먹이섭취 시 유생이 에너지원으로 활용할 수 있는 cholesterol, triglyceride의 증가가 있었으며 삼투압에 영향을 미칠 수 있는 glucose 농도가 유의적으로 증가하였다. 또한 저염분 순치기간 동안에 스트레스, 조직손상 및 대사작용의 지표가 되는 BUN과 creatine의 감소가 있었다. 먹이섭취로 인한 소화효소의 활성이 먹이를 섭취한 실험구 모두에서 증가하였다. 그러므로 유생발달과 함께 중요한 소화, 순환, 생식기관이 형성되며 탈피 성장을 위한 신진대사가 빠르게 진행되는 유생시기에 저염분 순치가 효율적으로 이루어져 향후 지속적인 성장을 유도하기 위해서는 먹이를 섭취하는 것이 더 효과적인 것으로 판단되었다.

• 한국어병학회지
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• 제35권2호
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• pp.167-176
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• 2022

We injected infectious myonecrosis virus (IMNV) to pacific whiteleg shrimp, Litopenaeus vannamei, and observed closely with using light microscope and transmission electron microscope (TEM) for 4-8 days post infection (dpi). As clinical signs, abdominal bodies had mild opaque muscles at 5 dpi. And the mortality was shown at 6 dpi. At 8 dpi, most injected shrimps had severe opaque muscles and humped back that cause of movement disorder. As results of histopathological examinations, local parts of abdominal body muscle had muscle fiber hyalinization, muscle fiber atrophy, rounded muscle fibers, myofibrillar hypertrophy in size, a decrease in number of myofibrils and phagocytosis from the sarcolemmas by multiple hemocytes at 4 dpi. Especially, myofibrillar hypertrophy appeared at the whole or random part of single muscle fiber not in specific locations like the center or edge of muscle fiber. At 6-7 dpi, multiple muscle necrosis, muscle fiber segmentation, myofibril lysis ap- peared and a few hemocytes were infiltrated at lesions. At 8 dpi, extensive muscle necrosis, multiple myofibril lysis and muscle fiber atrophy were shown, and very few hemocytes were infiltrated. In early stage of infection, local viral myositis with zenker's degeneration were shown. These lesions appeared multiply after the early stage. In late stage of infection, extensive coagulative muscle necrosis appeared with few of inflammatory response such as hemocytes infiltration. The lack of hemocytes infiltration response at the late stage might be disadvantage for Litopenaeus vannamei to defense against IMNV and to recover, because hematocytes (granulocyte, semi-granulocyte) eliminate pathogen and damaged tissues from infection sites and help recover. As results of the TEM observation, IMNVs that had nonenveloped icosahedral capsid which was 30-40 nm diameter were in myofibril and beside tubules of sarcoplasmic reticulum and moved to the certain direction. The micro-tears and micro-trau- mas in myofibrils caused muscle fiber necrosis. And semi-granulocytes engulfed IMNVs to eliminate virus.