• Journal of Marine Life Science
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• v.3 no.2
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• pp.67-73
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• 2018

This study was conducted to investigate the influence of environmental factors such as water temperature, salinity, rearing density and feeding amount on the survival and development of larvae in surf clam, Tresus keenae. As a result of this study, the optimum conditions of larval rearing were as follows. The optimum range of water temperature is 20℃ to 24℃, the optimum salinity is 30 psu, the optimum rearing density is 5 ind./ml and the supply of mixed feed organism for larva rearing such as Isochrysis galbana, Chaetoceros simplex and Tetraselmis suecica is 10×10⁴ cells/ml. The results of this study suggest that the optimum conditions of environmental factors in larval rearing of Tresus keenae contribute to productivity improvement through rapid growth and high survival.

• Parasites, Hosts and Diseases
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• v.51 no.4
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• pp.427-432
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• 2013

A new trichostome ciliate, Balantidium honghuensis n. sp., was isolated from the recta of Rana nigromaculata and R. limnocharis during parasite surveys in Honghu Lake, Hubei Province, central China in summmer of 2010 and 2011. Its detailed morphometric characters based on LM and SEM studies were described herein. The organism is oval in shape and thickly ciliated. The vestibulum is "V" shaped and occupies about 1/3 to 2/5 of the body length. The vestibular and nearby regions possess strong peripheral fibers which form a marked axial fiber about the cytopharynx. More than 10 contractile vacuoles are distributed along the periphery of the latter body. Comparisions were made between this new species and B. sinensis Nie, 1935. They were discriminated from each other in terms of general body forms, body size, and vestibulum shapes. Besides, special attention was paid to its high-speed daughter swarmers which we believed to be the infective stage of B. honghuensis. Possible infection routes of anura amphibian balantidia were discussed.

• Journal of Applied Biological Chemistry
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• v.57 no.2
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• pp.183-188
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• 2014

In order to increase the nutritional quality of soybean meal (SBM) as an animal feed, Bacillus subtilis TP6, a previously isolated strain from an Indonesian traditional fermented soybean food, Tempeh, was used as a starter organism for solid-state fermentation. In the pre-treated SBM with water content of 60% (v/w), B. subtilis TP6 was grown to a maximum viable cell number of $3.5{\times}10^9CFU/g$. Compared to control, crude protein in Bacillus fermented SBM was increased by 16%, while raffinose, stachyose, and trypsin inhibitors were reduced by 31, 37, and 90%, respectively. The Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that proteins in the fermented SBM were remarkably hydrolyzed into smaller molecular masses, resulting in a decrease in large sized proteins. Our data suggested that B. subtilis fermentation could increase the nutritive value of SBM through reduction of anti-nutritive factors and improvement of protein quality by hydrolysis of soy protein. In addition, B. subtilis TP6 produced a functional ingredient, poly-${\gamma}$-glutamic acid which has various health benefits.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.805-816
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• 2024

The aim of this study was to evaluate a new Bacillus amyloliquefaciens B-1895 probiotic as a feed additive for farmed trout. Final weight, absolute and average daily gain of fish, and average daily growth rate were higher in the group that received the probiotic than in the control group (p<0.05). Moreover, the probiotic-fed trout had more intense growth rates than the control group (higher by 15.7%; p<0.05). A decrease in feed ratio was also observed in the group that received probiotic (25% decrease; p<0.05), indicating more efficient digestion and assimilation of feed. In general, the introduction of probiotic in the feed did not adversely affect the functional status of the fish. In young trout of the control group, when assessing the general chemical composition of the organism in the muscle tissue revealed significantly (p≤0.001) higher level of moisture content by 5.1% and lower by 11.0% dry matter content. In muscle, the protein content was higher by 1.33% (p≤0.001) and fat content by 2.1% (p≤0.001) in experimental fish. Generally, Lactobacilli, Enterococcus, Vibrio, Bacillus, and coliform bacteria were found in the intestinal samples of rainbow trout. Significant reliable difference (p≤0.05) between the samples of experimental and control groups was noted in the content of Bacillus bacteria. In the control group, 5.0±0.4×10³ CFU/g was detected, while in the experimental group 8.4±0.8×10⁴ CFU/g. Overall, the data indicate that probiotic bacteria B. amyloliquefaciens B-1895 has no adverse effect on selected microorganisms in the study fish.

• Journal of Life Science
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• v.32 no.8
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• pp.641-646
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• 2022

There are concerns about the environmental release of living modified organism (LMO) maize created to increase yields. In fact, there are cases in which LMO crops for feed have been leaked in Korea to form autoite colonies, and concerns about LMO spill are intensifying. In this study, the possibility of environmental outflow and occurrence of native organisms was analyzed using maize feed and seeds distributed in Korea. In the evaluation of the possibility of spontaneous occurrence of maize in the event of an unintentional release of maize feed made by crushing maize, the incidence rate of maize was 0.01%, which was extremely low compared to the germination rate of maize seeds. A survey of the dormant rate of maize showed that all maize seeds collected every month were dead. In the germination rate test by temperature using Daehak wax corn and Kwangpyeongok, high germination rates were found at 20℃ and 30℃, and relatively low germination rates were found at 10℃ and 40℃. In addition, all germination tests showed a higher germination rate Daehak wax corn than Kwangpyeongok. The difference between domestic and overseas cultivation maize was confirmed through a survey on the agricultural properties of three varieties of maize. The data obtained through this experiment could be the basis for the evaluation of the weediness potential of environmental risk assessment and technology to suppress the occurrence of autoite in preparation for future LMO spills.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1458-1468
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• 2002

There is increasing interest in exploiting natural products as feed additives to solve problems in animal nutrition and livestock production. Essential oils and saponins are two types of plant secondary compounds that hold promise as natural feed additives for ruminants. This paper describes recent advances in research into these additives. The research has generally concentrated on protein metabolism. Dietary essential oils caused rates of NH$_3$ production from amino acids in ruminal fluid taken from sheep and cattle receiving the oils to decrease, yet proteinase and peptidase activities were unchanged. Hyper-ammonia-producing (HAP) bacteria were the most sensitive of ruminal bacteria to essential oils in pure culture. Essential oils also slowed colonisation and digestion of some feedstuffs. Ruminobacter amylophilus may be a key organism in mediating these effects. Saponin-containing plants and their extracts appear to be useful as a means of suppressing the bacteriolytic activity of rumen ciliate protozoa and thereby enhancing total microbial protein flow from the rumen. The effects of some saponins seems to be transient, which may stem from the hydrolysis of saponins to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects which may prove useful in, for example, controlling starch digestion. These studies illustrate that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation, to the potential benefit of the farmer and the environment.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.830-835
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• 2004

An experiment of 10 weeks duration was carried out to study the influence of supplemental effective microorganism (EM) culture, yeast culture and enzymes on nutrient digestibility and gut microflora in rabbit gastrointestinal (GI) tract. Twenty four eight to nine weeks old, New Zealand White rabbits were allotted to four dietary treatments; a basal (control) feed, basal feed supplemented with either EM (1%), yeast culture or enzymes (400 ppm). Nutrient flow in digesta and their digestibility at ileum, caecum, colon and in the total tract as well as gut microflora distribution were studied. Feed dry matter was diluted from 92% to about 14% up to the ileum and about 95% of this water was reabsorbed by the colonic rectal segment followed by caecum (25%). EM and yeast improved protein digestibility at a lower rate than enzymes. Ileal, caecal, colonic and total tract digestibility of crude protein with enzymes were higher by 10.8, 9.4, 11.3 and 10.7%, respectively, as compared to the control. Yeast and enzymes increased crude fiber digestibility at ileum, caecum, colon and in the total tract by 8.5, 9.6, 9.0 and 8.3%, respectively, while EM improved them at a lower rate. Irrespective of treatments, total tract digestibility of crude protein (0.698-0.773) and fiber (0.169-0.183) were greater (p<0.05) than the ileal digestibility. Even though a post-caecal protein digestibility was observed, fiber digestion seemed to be completed in the caecum especially with yeast and enzymes. High precaecal digestibility of crude fiber (97%) and protein (95%) were observed even without additives probably due to caecotrophy. EM and yeast culture promoted the growth of lactic acid bacteria especially in the caecum but they did not influence gut yeast and mould. Present findings reveal that even though rabbits digest nutrients efficiently through hind gut fermentation, they can be further enhanced by EM, yeast and enzymes. Of the three additives tested, enzymes found to be the best.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.128-133
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• 2010

The Titanium has many superior characteristics which are specific strength, heat resistance, corrosion resistance, organism compatibility, non-magnetic and etc. and their quantity are abundant. this study performed turning operation of Ti-6Al-4V alloy using the TiAlN Coated Tool which treated Physical Vapor Deposition. Experimental works are also executed to measure cutting force, tool wear, chip figuration and surface roughness for different cutting conditions. As a result of study. Cutting depth influences on the cutting force much more than the feed rate and the value of the cutting force is the most stable at the depth of 1.0mm. And tool wear was serious at over 100m/min of cutting speed and cutting condition was excellent at 1.0mm of cutting depth.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.99-106
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• 2018

Extensive monitoring of aquatic organisms in rice paddy fields has been difficult due to laborious sampling methods such as quadrat sampling using a hand net. This study aimed to analyze temporal and regional community compositions of aquatic organisms collected with a less time-consuming sampling method. This method involved using submerged funnel traps in rice paddy fields. Submerged funnel traps were useful for capturing taxa containing species that are indicative of environmental changes and highly mobile species that feed on waterbirds. Fifteen taxa including Ampullariidae, Cobitidae, Chironomidae, Hydrophilidae and Dytiscidae determined the community compositions. Among the major taxa, only Chironomidae resistant to environmental disturbances represented temporal variations of aquatic organism communities in rice paddy fields. Ampullariidae, Dytiscidae, and Hydrophilidae, which are prone to be affected by anthropogenic activities, differed among regions.

• Journal of Korean Society of Forest Science
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• v.83 no.1
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• pp.1-5
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• 1994

Sixteen kinds of piercing-sucking mouth type insects were observed at witches'-broom diseased paulownia (Paulownia tomentosa) trees. Among ten insect species tested, a leafhopper, Empoasca sp., transmitted paulownia witches'-broom mycoplasma-like organism(PWB-MLO) to periwinkle(Catharanthus roseus) plant. Adults of this leafhopper were collected from PWB-diseased paulownia trees. The leafhpoppers were allowed to feed on the PWB-infected paulownia trees for three weeks to acquire PWB-MLO. These insects were then transferred to healthy seedlings of paulownia and periwinkle plants for inoculation-feeding. About 30-40days after the inoculation, "little-leaf" symptoms developed on periwinkle plants, but no symptoms developed on paulownia seedlings. MLO infection in the diseased periwinkle tissue was diagnosed by fluorescence microscopy. MLOs were observed in the sieve tubes by electron microscopy, proving the insect transmission of PWB-MLO.