• Korean Journal of Microbiology
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• v.54 no.4
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• pp.369-378
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• 2018

This study was conducted to evaluate effects of dietary microbial probiotics on the growth and disease resistance of olive flounder (Paralichthys olivaceus) in a recirculating aquaculture system (RAS), and the effects of the probiotic bioaugmentation on the microbial community structure and water quality. For the analysis, 80 juvenile fish (average weight, $25.7{\pm}7.6g$; average length, $15.2{\pm}1.7cm$) were fed a basal diet containing a commercial microbial product CES-AQ1 (CES; $1{\times}10^9\;CFU/kg$ diet) in an RAS for 8 weeks. Weight gain, the specific growth rate, feed efficiency, and protein efficiency ratio of the fish fed the CES diet in the RAS were 1.5~2.5 times higher than those of fish fed the basal diet alone, or the basal diet containing oxytetracycline (OTC), yeast plus bacterium, or Bacillus subtilis in a still water system. There was no significant difference in the pathogen challenge test between fish fed the OTC diet and fish fed the CES diet in the RAS, suggesting the CES-AQ1 probiotic used in the RAS as a potential replacement for antibiotics. The RAS biofilter maintained the highest microbial diversity and appeared to harbor microbial communities with ammonium oxidation, denitrification, and fish pathogen suppression functions. Ammonia, which is hazardous to fish, was significantly decreased to < 0.5 mg/L in 19 days, indicating the effectiveness of probiotic supplementation to maintain good water quality in RAS. These results suggest that the intestinal microbial communities of fish are stabilized by a probiotic-containing diet (CES) and that bioaugmentation with probiotics may be an eco-friendly and economical supplement for aquaculture of olive flounder, promoting both good water quality and fish health in an RAS.

• Animal Bioscience
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• v.34 no.12
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• pp.1963-1973
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• 2021

Objective: The present study aimed to evaluate the influence of including L-glutamine along with glutamic acid as a supplement in weaned piglets' diets with and without whey powder. Methods: Two assays were carried out. A total of 40 piglets ([Landrace×Large White]×Pietrain) weaned at 24 days of age with an initial body weight of 6.6±0.6 kg were used in the first assay, and the following parameters were evaluated: growth performance, the incidence of diarrhea, morphometry, intestinal integrity, and hepatic glycogen index. The animals were then blocked into four groups according to different diets: diet all-grain feeding (G); diet all-grain feeding with whey powder (GW); and with vs without 1% supplementation of the commercial product containing L-glutamine and glutamic acid (A or NA). Whey powder was added according to the stage of life, corresponding to 17%, 10%, and 5%, respectively, in order to meet the need for lactose. The animals were evaluated at 24 to 42 days and at 24 to 55 days of age. The nutrient digestibility for the second assay was carried out by using 24 animals with an average weight of 11.49±1.6 kg, and the same diets were tested. Results: The supplementation of L-glutamine + glutamic acid or the addition of whey powder in diets for weaned piglets provided (p<0.05) greater feed intake, greater weight gain and improved feed conversion in the initial period (24 to 42 days age). However, in the whole period (24 to 55 days age) only amino acid supplementation affected (p<0.05) growth performance. There was a positive interaction (p<0.05) between the type of diet and L-glutamine + glutamic acid supplementation on villus height, crypt depth and the villus:crypt ratio in the duodenum. In addition, L-glutamine + glutamic acid supplementation reduced (p<0.05) the crypt depth and improved the villus:crypt ratio in the jejunum. The inclusion of whey powder affected (p<0.05) positively the digestibility coefficients analyzed except mineral matter digestibility coeficients. The supplementation of 1% the commercial product composed of L-glutamine and glutamic acid improved (p<0.05) only the digestibility coefficient of crude protein. Conclusion: These results indicate that supplementation of 1% commercial product containing L-glutamine + glutamic acid in diets for piglets from 24 to 55 days of age, dispenses with the use of whey powder when evaluating growth performance. Amino acid supplementation alone or associated with whey powder affects (p<0.05) positively the indicators of the intestinal integrity.

• Journal of Aquaculture
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• v.16 no.2
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• pp.104-109
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• 2003

The present study aims to evaluate protein and phosphorus availabilities of five different dietary protein sources during the 6-week feeding trial in juvenile olive flounder, Paralichthys olivaceus as determined by growth performance and phosphorus retention. Five diets containing blood meal (BM), poultry by-product (PBP), squid liver powder (SLP), feather meal (FM) and soybean meal (SM) were prepared by mixing a basal diet (BD) with one of five test ingredients at the ratio of 7 to 3. As a reference diet, BD contains three different protein sources such as white fish meal, casein and gelatin. After 2 weeks of the conditioning period, fish initially averaging 2.7$\pm$0.02g (mean$\pm$SD) were randomly distributed into each aquarium as a group of 30 fish reared in the recirculating system. Fish of triplicate groups were fed one of six experimental diets (BD+five test diet). After 6-week feeding trial, pro- tein efficency ratio (PER) of fish fed BM diet was the lowest in experiment groups. While fish fed PBP diet showed a significant higher PER as compared to the FM diet, and fish fed SLP diet and BD were a higher PER than did fish fed PBP diet. However, there was no significant difference in PER among fish fed SLP diet, BD and SM diet, and between SM diet and PBP diet. Phosphorus retention efficiency of bone (PR $E_{b}$) of fish fed BM diet was the lowest in all the diets, and fish fed FM diet showed a higher PE $R_{b}$ than fish fed BD and SM diet. However, there was no significant difference in PER among fish fed FM diet, SLP diet and PBP diet, and among SLP diet, PBP diet, SM diet and BD. These results indicate that SLP could be a suitable protein source for low pollution diets of olive flounder in the future fish feeds market. Furthermore, PBP and SM are available protein source to reduce P waste in the oliver flounder aquaculture with the use of proper mixture of other protein sources and more processing to improve protein availibility of these.ese.

• Fisheries and Aquatic Sciences
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• v.21 no.8
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• pp.29.1-29.8
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• 2018

This study was conducted to evaluate the use of tuna by-product meal (TBM) as a substitute for fishmeal in juvenile Korean rockfish (Sebastes schlegeli) diets. Five isonitrogenous (52% crude protein) and isocaloric (4.9 kcal/g) diets were prepared. Control diet (Con) was formulated to contain brown fishmeal, whereas 25, 50, 75, and 100% of fishmeal was substituted with the same percentage of TBM in the TBM25, TBM50, TBM75, and TBM100 diets, respectively. Three replicate groups of fish (initial weight, $29.5{\pm}0.6g$) were fed one of the five diets for 12 weeks. The mean weight gain of fish fed the Con and TBM25 diets was significantly higher than that of fish fed the TBM100 diet (P < 0.05), but it was not significantly different from the weight gain of fish fed the TBM50 and TBM75 diets. The feed efficiency and protein efficiency ratios of fish fed the Con diet were significantly higher than those of fish fed the TBM100 diet (P < 0.05), but were not significantly different from those fed the TBM25, TBM50, and TBM75 diets. The TBM25, TBM50, TBM75, and TBM100 diets had significantly (P < 0.05) lower incidence cost and higher profit index than the Con diet. These results suggest that the tuna by-product meal used in this study could replace up to 75% of fishmeal protein in the diet without reducing growth and feed utilization in juvenile Korean rockfish weighing 29-53 g. By considering feed cost, the TBM 75 diet is recommendable for Korean rockfish farming.

• Natural Product Sciences
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• v.19 no.1
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• pp.61-65
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• 2013

A bioassay-guided fractionation of the extract of the fungus Paecilomyces variotii, which was derived from the giant jellyfish Nemopilema nomurai, led to the isolation of antibacterial compounds viriditoxin and its monomeric subunit semi-viriditoxin. Viriditoxin showed significant antibacterial activity against several marine fish and human pathogens including MDR strains. Significant potencies against resistant pathogens such as VRE Enterococcus faecium, VRE Enterococcus faecalis, and MRSA were highly interesting. Viriditoxin also showed notable antibacterial activity against the fish pathogen Streptococcus iniae. Its potency was over 100-fold higher than oxytetracycline which is employed as a general antibiotic for aquaculture.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.155-162
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• 2015

Abalone (Haliotis discus hannai) is a shellfish that feeds on kelp and, as a product, it can often achieve a high market value. However, the dissolved oxygen (DO) levels in coastal waters in Korea have been negatively impacted by pollution from many anthropogenic sources. Herein, a computational fluid dynamics (CFD) software package was used to analyze the distribution of the DO concentration within an abalone containment structure. A finite volume approach was used to solve the Reynolds-averaged Navier-Stokes equations combined with a $k-{\varepsilon}$ turbulence model to describe the flow. The distribution of DO was determined within the control volume domain, and the transport equations of the pollutants were interpreted using a CFD model. The CFD analysis revealed that more than 60% and 30% of the relative oxygen concentration in one and two containers, respectively, was maintained when the flow acts along the six sheets of polyethylene plates. Therefore, it is clear that the abalone plate shelters should be placed parallel to the flow.

• Natural Product Sciences
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• v.24 no.4
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• pp.225-228
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• 2018

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug- resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.772-778
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• 2016

To develop a value-added product from individually quick-frozen oysters Crassostrea gigas (IQFO), we prepared a retort pouched oyster soup (RPOS) from IQFOs and characterized its processing conditions and quality metrics. We found that the most appropriate manufacturing process for the RPOS consisted of half-thawing and washing raw IQF oysters, blanching, adding them to the retort pouch along with other ingredients (base soup stock, IQF oyster extract, radish, bean sprouts, garlic, and red pepper), sealing, retort sterilization ($120^{\circ}$, F0-value 10 min.), cooling, and packaging inspection. The moisture, crude protein, pH and salinity of the RPOS were 91.0%, 2.8%, 6.20 and 0.9%, respectively. The total amino acid content of the RPOS was 2,163.8 mg/100 g, and the main amino acids were glutamic acid, aspartic acid, leucine, proline, lysine and arginine. The primary inorganic ions were Na, K, S and Zn. In taste compounds, total free amino acid content was 313.4 mg/100 g, and the main free amino acids were glutamic acid, taurine, proline, hydroxyproline, aspartic acid, glycine, alanine, valine, lysine and arginine. This RPOS has good storage stability and organoleptic qualities compared with commercial retort pouched shellfish soup, and is suitable for commercialization as a value-added instant seafood soup.

• The Journal of Fisheries Business Administration
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• v.44 no.2
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• pp.19-33
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• 2013

China is the world's largest producer of aquatic products and its fishery sector is comprised primarily of aquaculture facilities, both fresh and seawater, and a much smaller wild catch component. The expansion of the aquaculture sector continues to boost China's aquatic output. The increase is attributable to several factors. Among them rapidly growing domestic demand is no doubt one of the most important reasons. Rapid economic growth and rising disposable income are influencing domestic consumption and the economic recovery of major import markets is further stimulating consumption of China's aquatic products. This paper tries to examine the status, trend and reasons of consumption of aquatic products in China. Based on the analysis on the consumption of aquatic products and its change, this paper utilizes panel regression model to estimate the affecting factors of aquatic products consumption in China. By using panel data between 1997 and 2010, the results indicate that income, urbanization, aging and dummy variable have positive effects and fish price index has negative effect on China's aquatic products consumption as predicted. However, effects of meat consumption and education on fishery consumption are totally opposite with our predictions. In other words, it turns out that meat consumption has positive effect on fish consumption while education turns out to have negative effect. Finally the member of household does not show any significant effect on consumption of aquatic products in China.

• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.7-12
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• 2008

Cameroon is a country in Western Africa with 16 million inhabitants. Located between Nigeria and Equatorial Guinea, the country is bordered by the Bight of Biafra. It has a 402 km long coastline. It covers an area of about 475,440 sq km. Cameroon obtains its fish supply from five distinct sources notably-small scale maritime Fisheries, inland fisheries, industrial fisheries, aquaculture and importation. Despite its enormous potential, Cameroon produces only 180,000 metric tons fish annually. The total artisanal annual catch is estimated to be 55,000 t of which bonga/Sardinella, white shrimp and demersal fish contribute 58%, 27% and 15% respectively. The industrial fleet expanded rapidly during the sixties and by 1973 there were 29 trawlers and 13 shrimpers which landed a total of about 17,600 t of fish and shrimp. The total catch of the industrial fisheries peaked at about 20,400 t in 1976 and since then catches have generally declined. The per capita fish consumption in Cameroon stands at about 17.9 kg per inhabitant per year. This means that the demand of fish in Cameroon stands at about 280,000 tons. There is a deficit of in fish supply for which the government always resort to massive importation of fish products to meet the local demand. The main fish product for export from Cameroon is the prawn (Panacus duorarum). The main export market of Cameroon's prawn is the European Union (EU). Between 1998 and 2003, Cameroon's export value has been on the decline, dropping from 1,836 metric tons of prawns for a value of 264 millions USD in 1998 to 51 tonnes, for an estimated value of 315,000 USD in 2003. This drastic drop in exportation is consequential to Cameroon's auto suspension from the exportation of prawns towards the EU as a result of non compliance with EU standards. Today, a good quantity of the catches is being exported illicitly through neighbouring countries.