• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1260-1269
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• 2024

The gastrointestinal (GI) tract of shrimp, which is comprised of the stomach, hepatopancreas, and intestine, houses microbial communities that play crucial roles in immune defense, nutrient absorption, and overall health. While the intestine's microbiome has been well-studied, there has been limited research investigating the stomach and hepatopancreas. The present study addresses this gap by profiling the bacterial community in these interconnected GI segments of Pacific whiteleg shrimp. To this end, shrimp samples were collected from a local aquaculture farm in South Korea, and 16S rRNA gene amplicon sequencing was performed. The results revealed significant variations in bacterial diversity and composition among GI segments. The stomach and hepatopancreas exhibited higher Proteobacteria abundance, while the intestine showed a more diverse microbiome, including Cyanobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Chloroflexi, and Verrucomicrobia. Genera such as Oceaniovalibus, Streptococcus, Actibacter, Ilumatobacter, and Litorilinea dominated the intestine, while Salinarimonas, Sphingomonas, and Oceaniovalibus prevailed in the stomach and hepatopancreas. It is particularly notable that Salinarimonas, which is associated with nitrate reduction and pollutant degradation, was prominent in the hepatopancreas. Overall, this study provides insights into the microbial ecology of the Pacific whiteleg shrimp's GI tract, thus enhancing our understanding of shrimp health with the aim of supporting sustainable aquaculture practices.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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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.

• Journal of fish pathology
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• v.33 no.1
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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.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.496-507
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• 2023

This study investigated species identification and labeling compliance of 48 shrimp products sold in the Korean online markets. Species identification was conducted using the standard DNA barcoding method, using the cytochrome c oxidase subunit I gene. The obtained sequences were compared with those deposited in the NCBI GenBank and BOLD Systems databases. Additionally, phylogenetic analysis was performed to further verify the identified shrimp species. Consequently, 16 shrimp species were identified, including Penaeus vannamei, Pandalus borealis, Palaemon gravieri, Leptochela gracilis, Penaeus monodon, Pleoticus muelleri, Metapenaeopsis dalei, Euphausia pacifica, Lebbeus groenlandicus, Trachypenaeus curvirostris, Argis lar, Metanephrops thomsoni, Metapenaeopsis barbata, Alpheus japonicus, Penaeus chinensis, and Mierspenaeopsis hardwickii. The most prevalent species was Penaeus vannamei, found in 45.8% of the analyzed products. A significant mislabeling rate of 72.9% was found; however, upon excluding generic names such as shrimp, the mislabeling rate reduced to 10.4%. The mislabeling rate was higher in highly-processed products (89.3%) compared with that in minimally-processed products (50%). No correlation was found between the country of origin and mislabeling rate. The results of this study provide crucial data for future monitoring of shrimp products and improving the labeling of shrimp species in Korea.

• Journal of fish pathology
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• v.35 no.2
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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.