• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1477-1482
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• 2001

Research in low cost feeds with high nutritional value and immunogenicity is important to reduce production cost and increase yields in the shrimp industry. In this study, immunostimulants of bacterial origin (peptidoglycan and lipopolysaccharides) and egg white were incorporated in shrimp diets as feed additives to determine the growth, survival and tolerance of Penaeus monodon to white spot syndrome virus (WSSV). Although the results obtained were not statistically significant (p>0.05) among the treatments, shrimp fed with bacterial additives and egg white showed higher weight gain, specific growth rate and survival than those fed on commercial shrimp diet. Shrimp fed with artificial diet showed 100% mortality when challenged with WSSV. However, shrimp fed on peptidoglycan supplemented diet had higher survival than their counterpart, whereas shrimp fed on egg white supplemented diet had a higher specific growth rate and better tolerance when challenged with WSSV. Further studies are required to determine the effectiveness and optimization of bacterial strains and egg white as feed additives to increase production and enhance the shrimp immune response to diseases.

• Journal of fish pathology
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• v.32 no.2
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.960-966
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• 2022

We aimed to determine the dietary myo-inositol (MI) requirements of Pacific white shrimp Litopenaeus vannamei. A basal diet was formulated without myo-inositol (M0) and a negative control diet (M0-) was prepared by adding tetracycline hydrochloride to the basal diet to prevent intestinal inositol synthesis. Five MI diets were prepared by adding MI at 300, 600, 900, 1,200 and 1,500 mg/kg to the basal diet (designated as, M300, M600, M900, M1200 and M1500, respectively). Triplicate groups of shrimp (initial body weight, 0.55±0.01 g) were fed one of the experimental diets for 42 days. The growth performance of shrimp in M0- group was significantly lower when compared to that of shrimp in M0, M1200 and M1500 groups. Feed efficiency was significantly improved in M1200 and M1500 groups when compared to the M0 and M0- groups. GPx activity was significantly higher in M1200 and M1500 groups compared to that in M0 and M0- groups. Therefore, a practical diet (over 240 mg/kg) meets the minimum MI requirements of Pacific white shrimp. However, the optimum dietary MI level would be potentially above 1,200 mg/kg for better feed utilization efficiency and antioxidant capacity of Pacific white shrimp.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.287-292
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• 2021

This study was conducted to evaluate the effects of dietary supplementation with shrimp soluble extract (SSE) on growth performance, feed utilization, innate immunity and digestibility of Pacific white shrimp Litopenaeus vannamei. A basal diet (Con) was formulated and three other diets were prepared with SSE supplementation at different levels of 1, 2 and 4% (designated as SSE1, SSE2 and SSE4, respectively). Triplicate groups of shrimp (1.20±0.01 g) were fed one of the experimental diets for 6 weeks. At the end of the feeding trial, growth performance and feed utilization of the shrimp were significantly improved by dietary supplementation of SSE4 compared to those of shrimp fed the Con diet. Shrimp fed SSE4 diet had significantly higher phagocytic activity than shrimp fed the Con diet. Dietary supplementation of SSE improved the protein and dry matter digestibility of shrimp. These results indicate that SSE can be used as a functional additive in the diets for Pacific white shrimp.

• BMB Reports
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• v.37 no.6
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• pp.726-734
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• 2004

White spot disease (WSD) is caused by the white spot syndrome virus (WSSV), which results in devastating losses to the shrimp farming industry around the world. However, the mechanism of virus entry and spread into the shrimp cells is unknown. A binding assay in vitro demonstrated VP28-EGFP (envelope protein VP28 fused with enhanced green fluorescence protein) binding to shrimp cells. This provides direct evidence that VP28-EGFP can bind to shrimp cells at pH 6.0 within 0.5 h. However, the protein was observed to enter the cytoplasm 3 h post-adsorption. Meanwhile, the plaque inhibition test showed that the polyclonal antibody against VP28 (a major envelope protein of WSSV) could neutralize the WSSV and block an infection with the virus. The result of competition ELISA further confirmed that the envelope protein VP28 could compete with WSSV to bind to shrimp cells. Overall, VP28 of the WSSV can bind to shrimp cells as an attachment protein, and can help the virus enter the cytoplasm.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.511-515
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• 2007

White-spot syndrome virus (WSSV) is a devastating, infectious virus affecting shrimp. Although sensitive techniques involving PCR have been developed to assist farmers in screening shrimp (brood stock) for WSSV prior to stocking ponds, such practices have not yet been applied in Korea. Despite the rationality of implementing screening, there has been some doubt as to whether the stocking of WSSV-PCR-negative fly epidemiologically decreases white-spot disease outbreaks. Here, we report a retrospective analysis of data from shrimp farms in the western coast of Korea where WSSV-PCR-negative brood stocks were used to stock rearing ponds. A total of 366 shrimp from Heuksan Island were sampled for WSSV with PCR. Of the tested shrimp, 7.2% (28 brood stocks) were identified as WSSV positive; only WSSV-PCR-negative shrimp were used for brood stocks. Total unit production (final shrimp production/ the area of the ponds) was higher, at 1.96, in ponds where WSSV-PCR-negative shrimp were used, as compared with 1.02 in other ponds in Korea in 2004. This retrospective analysis of WSSV in Korea may be useful to the shrimp aquaculture industry, suggesting a testable hypothesis that may contribute to the eventual control of WSSV outbreaks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.909-917
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• 2020

This study was conducted to evaluate dietary supplementation of Sargassum horneri (SH) meal on growth performance, feed utilization, innate immunity, antioxidant capacity and disease resistance of Pacific white shrimp. The diets were added with graded levels of SH meal by 0, 0.5, 1, 2, 4 and 8% (designated as Con, SH0.5, SH1, SH2, SH4 and SH8, respectively). Quadruplicate groups of shrimp were hand-fed with one of the diets five times daily for 39 days. The innate immunity and antioxidant capacity of shrimp were significantly improved by the dietary SH supplementation. The cumulative survival of shrimp exposed to Vibrio parahaemolyticus in a challenge was higher in shrimp group fed SH diets, except for SH8, than that of shrimp fed the control diet. Growth performance and feed utilization of the shrimp were significantly decreased with the dietary SH inclusions except for 0.5%. Results indicated that dietary SH meal could be used as a functional supplement for improvements in innate immunity, antioxidant capacity and disease resistance in Pacific white shrimp. The suggested dietary inclusion level of dried SH is approximately 0.5% for the shrimp.

• Journal of fish pathology
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• v.13 no.1
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• pp.15-20
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• 2000

Infection rates with white spot baculovirus(WSBV) in wild-caught shrimp spawners appeared to be 52% in Penaeus chinensis and 20% in Penaeus japonicus when diagnosed by polymerase chain reaction (PCR). Infection rates of WSBV from inhabitant organisms in shrimp farm showed 37% in Upogebia major and 29% in Calliamassa japonica. The viruses maintained their survivorship in seawater at $4^{\circ}C$, but lost it at $25^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.900-908
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• 2020

This study was conducted to partially replace fish meal with black soldier fly (BSF) larvae or mealworm (MW) larvae in the diet for Pacific white shrimp Litopenaeus vannamei. A tuna by-product meal (27%) was used as the protein source in a control (Con) diet, which was replaced with 20%, 40%, or 60% BSF (designated as BSF20, BSF40, and BSF60, respectively), or MW (MW20, MW40, and MW60, respectively). The shrimp (average body weight, 0.09 g) were randomly stocked in 28 acrylic tanks and quadruplicate groups were fed one of the experimental diets six times daily. After 57 days of the feeding trial, growth and feed efficiency were significantly higher in shrimp that were fed the BSF40 and BSF60 diets than those in shrimp fed the Con diet. Phenoloxidase, superoxide dismutase, glutathione peroxidase and gene expression of crustin were significantly higher in shrimp fed BSF or MW diets than those in shrimp fed the Con diet. The results indicate that BSF or MW could be used as a fish meal replacement or as a functional protein source in diets and can help improve the growth, feed utilization, innate immunity and antioxidant capacity of Pacific white shrimp.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1136-1141
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• 2011

Effect of dietary essential oils on growth, feed utilization and meat yields of white leg shrimp L. vannamei was investigated. White shrimp fry weighing 0.62 g were kept in one of 12 tanks (75 head/500 L holding tank) in a closed recirculation system. Four experimental diets, a commercial diet (control), phytoncide oil (PO), oregano oil (OO) and fermented garlic liquid (GL) were fed for 16 weeks. The mean water quality values for the whole experimental period were $27.8{\pm}1^{\circ}C$, $7.6{\pm}0.3$, $15.5{\pm}0.3$ g/L and $6.1{\pm}0.3$ mg/L for water temperature, pH, salinity and dissolved oxygen, respectively. At the end of the trial, 10 shrimp per tank were randomly sampled and meat yields (%) were evaluated after peeling the shell and removing the head. After a 16 week feeding trial, final weight of shrimp ranged from 21.9 g to 23.6 g. Feed conversion was not significantly different among groups (p>0.05), which was the lowest (1.95) in the control and highest (2.30) in the PO. Specific growth rate was also not significantly different (p>0.05) and ranged from 3.18% to 3.25%. Average daily gain of 0.2 g was obtained in all treatments. Mortality varied from 35.1% for control to 44.9% for OO. Meat yields maintained constant at 52.1% for control to 53.0% for PO. The study suggested that natural essential oils could not exert any improvement in growth performance, mortality and meat yields of white leg shrimp.