• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.3
• /
• pp.625-633
• /
• 2015

Olive flounder (Parlichthys olivaceus) is a large carnivorous fish that live at coastal area and shallow seas in Korea. It was good texture and clean taste because of a high collagen content and low lipid content. More than 70% of olive flounder annual production was traded alive, consequently processing food product from olive flounder is rare to be towed. This study was conducted to investigate the best method of olive flounder cutlet processing. Clean fillet (headless, skinless and contain no viscera part) of olive flounder were divided into 5 portion. Every 100 g of olive flounder meat was wrapped with vinyl then flatten with meat hammer. Flatten fillet then was coated with wheat flour, and seasoned with salt and pepper. These were then coated with egg wash and bread crumbs. Two different method of processing was to make this olive flounder cutlet. Cutlet-1 was fried for 1 min in olive oil, then kept in polyethylene film vacuum packaging ($20{\times}30{\times}0.05mm$) and stored at $-20^{\circ}C$ for 7 days. After 7 days the cutlet was thawed and heat up in microwave for 2 min (Sample-1). The other proup is cutlet-2, which is directly stored in polyethylene film vacuum packaging at $-20^{\circ}C$ for 7 days then thawed and fried for 1 min in olive oil (Sample-2). The factors such as pH, TBA value, amino-N, free amino acid, chemical composition, color value (L, a, b), texture profile, sensory evaluation and viable bacterial count of the olive flounder cutlet (Sample-1, Sample-2) were measured. From the result of sensory evaluation, Sample-2 showed a little high scores than Sample-1. But there was no significant differences in color, odor, taste, texture and overall acceptance between Sample-1 and Sample-2 products.

• Research in Plant Disease
• /
• v.14 no.1
• /
• pp.51-56
• /
• 2008

Powdery mildew of lettuce that is a newly reported disease became a threat to organic cultivation of lettuce in Korea since the disease caused by Podosphaera fusca resulted in a half of yield loss in heavily infected fields. To improve micro-environmental conditions around lettuce, ACF (air-circulation fan) was installed on inside roof of plastic house at 6 m intervals. The ACF increased 57% of lettuce yield and reduced 71.4% of lettuce seedling death. COY (cooking oil and yolk mixture) consisted of cooking oil 0.3% and egg yolk 0.08% reduced lettuce seedling death from 89.3% to 92.9% under the greenhouse. Seven-day interval spray of COY resulted in high control values of powdery mildew of lettuce ranging from 89.6% to 96.3%, which was comparable to a fungicide, Azoxystrobin. Lettuce yield was increased about two times compared to a non-treated conventional cultivation. Qualities of lettuce such as hardness and chlorophyll content were also improved by COY and ACF combination. Effect of COY on control of the disease was improved when $CaCO_3$ or $SiO_2$ 1,000 ppm was supplemented. Results indicated that the COY made of cooking oil such as canola emulsified with yolk was highly effective on control of powdery mildew of lettuce and suitable for organic agriculture, especially when combined with ACF.

• Korean Journal of Poultry Science
• /
• v.43 no.2
• /
• pp.111-118
• /
• 2016

Mycotoxins are secondary metabolites produced by molds, such as Aspergillus, Fusarium and Penicillium, that have adverse effects on animals and humans. Aflatoxin, ochratoxin, zearalenone, fumonisin and deoxynivalenol are the mycotoxins of greatest agro-economic importance and cause acute disease called mycotoxicoses. Mycotoxicosis in poultry birds results in decreased meat/egg production, immunosuppressant, and hepatotoxicosis. Some of toxins or their metabolites may be retained in animal or human tissues and induce health problems. This study was designed to develop a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous detection and quantification of mycotoxins, such as aflatoxin $B_1$, aflatoxin $M_1$, ochratoxin A, zearalenone, fumonisin B and deoxynivalenol, in chicken liver and kidney tissues. The mycotoxins were extracted and purified using modified QUECHERS methods, separated by LC and detected by an electrospray ionisation interface (ESI) and tandem MS. Good precision and linearity were observed for most of six mycotoxins. The recovery test for each mycotoxin in liver and kidney tissues mostly indicated good average recovery rates between 80.94% and 98.10% and the coefficient of variation mostly under 13.78%, except for aflatoxin $M_1$ and fumonisin $B_1$. The limit of detection (LOD) for six mycotoxins was $7.6{\sim}145.79{\mu}g/kg$ in liver tissues and $6.07{\sim}197.20{\mu}g/kg$ in kidney tissues. The quantification limits (LOQ) for 6 mycotoxins were in the range $23.04{\sim}441.78{\mu}g/kg$ in liver tissues and $18.40{\sim}597.59{\mu}g/kg$ in kidney tissues, respectively. The developed multi-mycotoxin method in this study permits simultaneous, simple, and rapid determination of several co-existing mycotoxins in chicken liver and kidney tissues.

• Korean Journal of Ecology and Environment
• /
• v.40 no.3
• /
• pp.379-386
• /
• 2007

Nonylphenol (NP) has been well known as a major substance of surfactant and/or estrogenic environmental hormone. We tested toxic effects of nonylphenol on the population growth and development of aquatic organism such as algae (Microcystis aeruginosa), heterotrophic nanoflagellate (Diphylleia rotans), micro- (Brachionus calyciflorus) and macro-zooplankton (Daphnia magna) among eutrophic water food-web constituents. Dosage of NP treatment were 4 to 5 grades, according to each organism's tolerance based on pre-experiments; algae (0.01, 0.05, 0.10, 1.00 mg $L^{-1}$) Diphylleia rotans (0.5, 1,2. 5,6, 10 ${\mu}g\;L^{-1})$, Brachionus calyciflorus (0.1, 0.5, 1, 2.5, 5 ${\mu}g\;L^{-1}$), and Daphnia magna (0.5, 1, 5, 10, 50 ${\mu}g\;L^{-1}$), respectively. Toxic effects were measured by the changes of biomass of each organism after NP treatment. All experiments were triplication. As suggested, the higher concentration of NP treatment, the stronger inhibited the population growth of all organisms tested. In view of toxicity, a variety of concentration of NP showed a significant growth inhibition to organism; algae to 0.05 $mg\;L^{-1}$, D. rotans and B. calyciflorus to 1.0 ${\mu}g\;L^{-1}$, and D. magna to 5.0 ${\mu}g\;L^{-1}$, respectively. The $EC_{50}$ of each organism to the nonylphenol are as follows; 3. calyciflorus (2.49 ${\mu}g\;L^{-1}$), D. rotans (3.49 ${\mu}g\;L^{-1}$), D. magna (7.61 ${\mu}g\;L^{-1})$, and M. aeruginosa (47 ${\mu}g\;L^{-1})$. NP toxic effects on the development of zooplankton like egg production showed some differences in treatment concentration between Brachionus calyciflorus ${0.1{\sim}1NP{\mu}g\;L^{-1})$ and Daphnia magna $(0.5{\sim}5NP\;{\mu}g\;L^{-1})$. These results suggest that a strong growth inhibition of predator or grazer by the nonylphenol can stimulate the algal growth, or can play important role in evoking the nuisance algal bloom in eutrophic water with enough nutrients.

• Korean Journal of Heritage: History & Science
• /
• v.56 no.3
• /
• pp.214-232
• /
• 2023

Stromatolite at the Daegu Catholic University, Gyeongsan was designated as a natural monument in December 2009 because it was very excellent in terms of rarity, accessibility, preservation and scale. From the time of designation, the necessity of confirming the lateral extension of the stromatolite beds with the excavation of the surrounding area, and preparing a preservation plan was raised. Accordingly, the Cultural Heritage Administration conducted an investigation of the scale, production pattern, and weathering state of stromatolites with an excavation from April to December 2022, and based on this, suggested natural heritage values and conservation and use plans. The excavation was carried out in a 1,186m² area surrounding the exposed hemispherical stromatolite (approximately 30m2). Stromatolites are continuously distributed over the entire excavation area, and hemispherical stromatolites predominate in the eastern region, and the distribution and size of hemispherical domes tend to decrease toward the west. These characteristics are interpreted as a result of long-term growth in large-scale lakes, where stratiform or small columnar domes continued to grow and connect with each other, finally forming large domes. Consequently, large and small domes were distributed on the bedding plane in clusters like coral reefs. The growth of plants and lichens, as well as small-scale faults and joints developed on the stromatolite bedding surface, is the main cause of accelerated weathering. However, preservation treatment with chemicals as with dinosaur footprints or dinosaur egg fossil sites is not suitable due to the characteristics of stromatolites, and preservation with the installation of closed protection facilities should be considered. This excavation confirmed that the distribution, size and value of stromatolites are much larger and higher than at the time of designation as a natural monument. Therefore, additional excavation of areas by experts that could not be excavated due to the discovery of buried cultural properties (stone chamber tombs) and reexamination of the expansion designation of natural monuments are required.

• Applied Biological Chemistry
• /
• v.18 no.3
• /
• pp.145-166
• /
• 1975

The calcium balance study was carried out to determine the availability of calcium in different sources for chicks and laying hens. The sources of calcium were calcium carbonate (CC), dicalcium phosphate-dihydrate (DCPH), and dicalcium phosphate-anhydride (DCPA) for chicks and calcium carbonate (CC) and oyster shell (OS) for laying hens. The radioisotope dilution method was employed to measure the endogenous excreta calcium during the period of balance study following preliminary feeding. A. Experimental results with chicks: No significant difference was found among feed consumption of chicks fed diets containing different sources of calcium. Body weight gain of chicks was dependent upon the source of calcium. The gain decreased in the order of DCPH, DCPA and CC (P<0.01). The feed conversion efficiency in chicks fed DCPH was better than those in chicks fed CC or DCPA. The average tibia ash contents for chicks fed different sources of calcium were similar. The DCPH was superior to CC or DCPA regarding the calcium content in tibia ash. There were no significant differences among the average calcium contents in plasma trichloracetic acid filtrate in chicks irrespective of calcium sources. The mean apparent retention of calcium by chicks fed DCPH, CC and DCPA were 65.9, 64.0 and 59.9% respectively. The calcium to phosphorus ratios in tibia ash and plasma trichloracetic acid filtrate for chicks fed different sources of calcium were similar. The chicks fed DCPH showed the partition of endogenous excreta calcium in total excreta calcium as 35.6% which was higher than 31.0 or 31.4% for chicks fed CC or DCPA. The endogenous excreta calcium per day per chick in group fed DCPH, DCPA or CC were 17.2, 16.1 and 14.6mg respectively. The true retained calcium per day per chick in group fed DCPH were 109.9 mg which was higher than those observed with CC or DCPA group (P<0.01). The true retention of calcium by the birds fed diets containing DCPH, CC or DCPA were 78.1, 75.1 or 72.6% respectively. B. Experimental results with laying hens: The feed consumption, egg production and feed converion efficiency of laying hens fed diets containing different sources of calcium were similar. Calcium concentration in plasma trichloracetic acid filtrate in laying birds fed CC was equivalent to the value obtained by feeding OS. The apparent calcium retention by laying birds fed CC was 61.6% and it was significantly more than that of hens fed OS of 51.6% (P<0.05). The partition of endogenous excreta calcium in total excreta calcium of laying hens fed CC was 23.5% and this was higher than that of birds fed OS of 15.6%. The laying hens fed CC showed 310 mg of endogenous excreta calcium per day per bird while birds fed OS showed 261mg. The true retention of calcium by layers fed CC was 70.7% against 59.2% for birds fed OS (P<0.05).

• Journal of Aquaculture
• /
• v.9 no.1
• /
• pp.25-42
• /
• 1996

The study has been conducted to know an appropriate feeding strategy and effects of the rearing density on larval growth of the rockfish, Sebastes schlegeli. The results obtained are as fellowed ; 1. Thirty-day-old larvae reached at $25.25{\pm}3.76$ mm in total length and $0.23{\pm}0.07$ g in body weight in experiment A, at which rotifer was provided from the beginning to the end of 30-day experiment, Anemia from 3th to 18th day, and artificial feed from 13th to 30th day after hatching. When rotifer was provided for 30 days, Artemia from 6th to 18th day, and artificial feed from 18th to 30th day after hatching (experiment B), these larvae grew up to $27.52{\pm}2.50$ mm in total length and $0.26{\pm}0.06$ g in body weight. On the other hand, when rotifer and artificial feed were supplied with the same time schedule as shown in experiment B, and Artemia was feed from 6th to 30th day after hatching (experiment C), the total length and body weight of those larvae were $23.22{\pm}3.44$ mm and $0.15{\pm}0.05$ g, respectively. The best result for larval growth was obtained from experiment B. The survival rates estimated were $57.6\%$ in experiment A, $66.4\%$ in experiment B, and $44.4\%$ in experiment C. 2. The growth in total length of the larvae according to their rearing days could be represented by the following equations : Experiment A : Y=4.350+0.116X+$1.887X^2$ (r=0.993) Experiment B : Y=4.500+8.931X+$2.221X^2$ (r=0.994) Experiment C : Y=4.478+5.734X+$1.881X^2$(r=0.990) The average number of Artemia nauplius intaken by the larvae was rapidly increased between 15th and 20th day afer hatching, and 9, 212, 242, 750, and 1,171 nauplius were found in the different sizes of larvae, whose total length were 5.65, 6.81, 9.45, 14.96, and 24.52 mm, respectively. 3. Larval growth in total length and body weight reared at four different densites (A: 1.8 $kg/m^3$, B; 4.0 $kg/m^3$, C; 5.0 $kg/m^3$, D; 6.2 $kg/m^3$) indicated that the best growth was found in experiment A, at which the larval were reared at the lower density and the final survival rates extimated were $92.9\%$ in exp. A, $99.5\%$ in exp. C, $89.0\%$ in exp. B, and $88.2\%$ in exp. D. The amount of production per cubic meter turned out to be 30.45 kg in exp. D, 25.89 kg in exp. C, 20.75 kg in exp. B and 10.48 kg in exp. A. therefore, considering both larval growth and survival rate, higher yields seemed to be attainable at the relatively high-rearing density.