• 한국토양비료학회지
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• 제25권4호
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• pp.334-341
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• 1992

석천미사질토양(石泉微砂質土壤)의 답전륜환포장(畓田輪換圃場)에서 수도(水稻)의 생산력변화와 식물체중의 무기성분흡수양상(無機成分吸收樣相)의 특징(特徵)등에 대해서 수도연작구(水稻連作區)와 수환구(輸換區)와를 비교검토(比較檢討)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 정조수량(精租收量)은 '90년(年)(2년차(年次)) 및 '91년(年)(3년차(年次))에서 벼연작구(連作區)에 비하여 매년윤환구(每年輪換區) 및 2년윤환구(年輪煥區)의 감자, 배추구(區)>대두구(大豆區)>대두구(大豆區))>벼연작구(連作區)의 순(順)이며 증수요인(增收要因)은 주당수수(株當穗數), 수당립수(穗當粒數)의 증가(增加)와 등숙률(登熟率)의 향상(向上)에 기인(基因)되었다. 2. 2년간(年間)('90~'91년(年))의 수확기(收穫期) 무기성분함량(無機成分含量) 및 흡수량(吸收量)은 수량(收量)의 증수경향(增收傾向)과 같은 양상(樣相)으로 증가(增加)되었으며 특(特)히 3년차(年次)('91년(年))의 무기성분흡수량(無機成分吸收量)이 질소시비수준(窒素施肥水準)에 따라 증대(增大)되는 경향(傾向)이었다. 3. 2년차(年次)('90년(年)) 수도흡수질소(水稻吸收窒素)의 토양유내(土壤由來)의 질소(窒素)는 수도연작구(水稻連作區)<매년윤환대두구(每年輪換大豆區)<매년윤환(每年輪換)감자, 배추구(區)의 순(順)이었다. 4. 군락상태하(君落狀態下)에서 수도엽색(水稻葉色)의 경시적(經時的) 변화(變化)는 토양용액중(土壤溶液中)의 암모니아태질소함량(態窒素含量)에 따라 변화(變化)되는 양상(樣相)이 큰 경향(傾向)이다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2001년도 추계학술강연 및 발표대회
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• pp.7-7
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• 2001

The increasing interest in light weight materials coupled to the need for cost -effective processing have combined to create a significant opportunity for aluminum P/M. particularly in the automotive industry in order to reduce fuel emissions and improve fuel economy at affordable prices. Additional potential markets for Al PIM parts include hand tools. Where moving parts against gravity represents a challenge; and office machinery, where reciprocating forces are important. Aluminum PIM adds light weight, high compressibility. low sintering temperatures. easy machinability and good corrosion resistance to all advantages of conventional iron bm;ed P/rv1. Current commercial alloys are pre-mixed of either the AI-Si-Mg or AL-Cu-Mg-Si type and contain 1.5% ethylene bis-stearamide as an internal lubricant. The powder is compacted in closed dies at pressure of 200-500Mpa and sintered in nitrogen at temperatures between $580~630^{\circ}C$ in continuous muffle furnace. For some applications no further processing is required. although most applications require one or more secondary operations such as sizing and finishing. These sccondary operations improve the dimension. properties or appearance of the finished part. Aluminum is often considered difficult to sinter because of the presence of a stable surface oxide film. Removal of the oxide in iron and copper based is usually achieved through the use of reducing atmospheres. such as hydrogen or dissociated ammonia. In aluminum. this occurs in the solid st,lte through the partial reduction of the aluminum by magncsium to form spinel. This exposcs the underlying metal and facilitates sintering. It has recently been shown that < 0.2% Mg is all that is required. It is noteworthy that most aluminum pre-mixes contain at least 0.5% Mg. The sintering of aluminum alloys can be further enhanced by selective microalloying. Just 100ppm pf tin chnnges the liquid phase sintering kinetics of the 2xxx alloys to produce a tensile strength of 375Mpa. an increilse of nearly 20% over the unmodified alloy. The ductility is unnffected. A similar but different effect occurs by the addition of 100 ppm of Pb to 7xxx alloys. The lend changes the wetting characteristics of the sintering liquid which serves to increase the tensile strength to 440 Mpa. a 40% increase over unmodified aIloys. Current research is predominantly aimed at the development of metal matrix composites. which have a high specific modulus. good wear resistance and a tailorable coefficient of thermal expnnsion. By controlling particle clustering and by engineering the ceramic/matrix interface in order to enhance sintering. very attractive properties can be achicved in the ns-sintered state. I\t an ils-sintered density ilpproaching 99%. these new experimental alloys hnve a modulus of 130 Gpa and an ultimate tensile strength of 212 Mpa in the T4 temper. In contest. unreinforcecl aluminum has a modulus of just 70 Gpa.

• Journal of Animal Science and Technology
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• 제58권1호
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• pp.4.1-4.7
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• 2016

Background: This study was conducted to evaluate the effects of adding Korean rice wine residue (RWR) in total mixed ration (TMR) on in vitro ruminal fermentation and growth performance of growing Hanwoo steers. Methods: For in vitro fermentation, the experimental treatments were Control (Con: 0 % RWR + TMR), Treatment 1 (T1: 10 % RWR + TMR), and Treatment 2 (T2: 15 % RWR + TMR). The rumen fluid was collected from three Hanwoo steers and mixed with buffer solution, after which buffered rumen fluid was transferred into serum bottles containing 2 g dry matter (DM) of TMR added with or without RWR. The samples were then incubated for 0 h, 12 h, 24 h, or 48 h at $39^{\circ}C$ and 100 rpm. For the in vivo experiment, 27 Hanwoo steers (6 months old) with an average weight of $196{\pm}8.66kg$ were subjected to a 24-week feeding trial. The animals were randomly selected and equally distributed into three groups. After which the body weight, feed intake and blood characteristics of each group were investigated. Results: The pH of the treatments decreased significantly relative to the control during the 12 h of incubation. Total gas production and ammonia nitrogen ($NH_3-N$) was not affected by RWR addition. The total volatile fatty acid (VFA) was lower after 24 h of incubation but at other incubation times, the concentration was not affected by treatments. Feed cost was 8 % and 15 % lower in T1 and T2 compared to control. Blood alcohol was not detected and a significant increase in total weight gain and average daily gain were observed in Hanwoo steers fed with RWR. Conclusion: Overall, the results of this study suggest that TMR amended with 15 % RWR can be used as an alternative feed resource for ruminants to reduce feed cost.

• Asian-Australasian Journal of Animal Sciences
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• 제8권1호
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• pp.43-50
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• 1995

This study was carried out to investigate the effects of activated carbon (AC) on growth, ruminal charateristics, blood profiles and feed digestibility in sheep, using roughage-based or concentrate-based diets. Twelve Suffolk breed of sheep of similar age and weight were distributed into 4 groups in a $2{\times}2$ factorial design. Two groups were fed a roughage-based diet with (R + AC) and without AC (R - AC), while the other two were fed a concentrate-based diet with (C + AC) and without AC (C - AC), respectively. The addition of 0.3% AC was based on dry matter of feed offered to animals. The incorporation of AC in roughage and concentrate based diets had no marked effects on feed intake, daily gain and feed conversion of the animals within experimental diets. The results obtained might be due to the low level of AC added in the diet. The animal on both concentrate-based diets were higher than the roughage-based diets in terms of daily gain and feed conversion ratio. However, it was observed that the animals provided with AC in the concentrate-based diet did not suffer from diarrhea and easily adjusted to high concentrate feeding. Further, the pH value for all diets before feeding was noted to be similar. After feeding, however, pH was shown to be higher in R + AC (p < 0.05) than in C + AC diet. Rumen protozoa number was decreased after feeding for both + AC diets, but in C - AC diet it was higher than in the roughage-based diets. For ammonia-nitrogen, C - AC was found to be higher than C + AC diet and the roughage-based diets before feeding. Total volatile fatty acid concentration, propionate and valerate molar ratios for both diets and time of collection were not affected. However, acetate, butyrate and valerate molar ratios were observed to be affected by diets and time of collections. The diets with AC increased (p < 0.05) before feeding for acetate molar ratio, but not different within diet, however, the roughage diets were found to be higher (p < 0.05) in acetate than the concentrate diet. In the blood parameters, the glutamic pyruvic transaminase (GPT), red and white blood cell (RBC, WBC) counts and packed cell volume (PCV) did not differ within and among the diets. Likewise, the WBC differential count in both diets with either - AC or + AC were similar in trend. However, lymphocyte count was noted to be increased in R + AC than the R - AC diet. The addition of AC in both diets did not affect nutrient digestibilities within diets.

• Asian-Australasian Journal of Animal Sciences
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• 제28권9호
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• pp.1296-1302
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• 2015

This study was conducted to examine the effects of supplementing brown seaweed by-products (BSB) in the diet of ruminants on ruminal fermentation characteristics, growth performance, endocrine response, and milk production in Holstein cows. In Experiment 1, the effects of different levels (0%, 2%, and 4% of basal diet as Control, 2% BSB, 4% BSB, respectively) of BSB were evaluated at 3, 6, 9, 12, and 24 h in vitro batch culture rumen fermentation. The pH tended to be higher for the higher level of BSB supplementation, with the pH at 12 h being significantly higher (p<0.05) than that of the control. The concentration of ammonia nitrogen was lower at 3, 9, 12, and 24 h incubation (p<0.05) compared with the control, and tended to be low at other incubation times. Volatile fatty acid concentration appeared to be minimally changed while lower values were observed with 4% BSB treatment at 24 h (p<0.05). In Experiment 2, effects of levels (0%, 2%, and 4%) of BSB on growth performance, endocrine responses and milk production were studied with Holstein dairy cows during transition. Dry matter intake, daily gain and feed efficiency were not affected by BSB supplementation. The concentration of plasma estrogen for the control, 2% BSB and 4% BSB after three months of pregnancy were 55.7, 94.1, and 72.3 pg/mL, respectively (p = 0.08). Although the differences of progesterone levels between BSB treatments and the control were minimal, the concentration in 4% BSB treatment increased to 157.7% compared with the initial level of the study. Triiodothyronine and thyroxine levels were also higher after both three months and eight months of pregnancy than the initial level at the beginning of the study. In addition, BSB treatments during one month after delivery did not affect daily milk yield and composition. In conclusion, the present results indicate that supplementation of BSB did not compromise ruminal fermentation, and animal performance at lower levels and hence may have potential to be used as a safe feed ingredient in dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• 제29권2호
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• pp.230-240
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• 2016

Information on the effects of different yeast species on ruminal fermentation is limited. This experiment was conducted in a $3{\times}4$ factorial arrangement to explore and compare the effects of addition of three different live yeast species (Candida utilis 1314, Saccharomyces cerevisiae 1355, and Candida tropicalis 1254) at four doses (0, $0.25{\times}10^7$, $0.50{\times}10^7$, and $0.75{\times}10^7$ colony-forming unit [cfu]) on in vitro gas production kinetics, fiber degradation, methane production and ruminal fermentation characteristics of maize stover, and rice straw by mixed rumen microorganisms in dairy cows. The maximum gas production (Vf), dry matter disappearance (IVDMD), neutral detergent fiber disappearance (IVNDFD), and methane production in C. utilis group were less (p<0.01) than other two live yeast supplemented groups. The inclusion of S. cerevisiae reduced (p<0.01) the concentrations of ammonia nitrogen ($NH_3$-N), isobutyrate, and isovalerate compared to the other two yeast groups. C. tropicalis addition generally enhanced (p<0.05) IVDMD and IVNDFD. The $NH_3$-N concentration and $CH_4$ production were increased (p<0.05) by the addition of S. cerevisiae and C. tropicalis compared with the control. Supplementation of three yeast species decreased (p<0.05) or numerically decreased the ratio of acetate to propionate. The current results indicate that C. tropicalis is more preferred as yeast culture supplements, and its optimal dose should be $0.25{\times}10^7$ cfu/500 mg substrates in vitro.

• 한국수산과학회지
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• 제43권4호
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• pp.331-339
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• 2010

Shrimp farming is the most important mariculture industry on the west coast of South Korea. However, it has suffered from mass mortality due to viral disease outbreaks and coastal pollution due to water discharge. This study developed an intensive shrimp culture method for outdoor ponds, without water exchange, which minimizes the chance of viral transmission from the environment, reduces coastal pollution by water discharge and enhances shrimp production. A culture trial was conducted in two high-density polyethylene (HDPE)-lined ponds with a $550\;m^2$ surface area. The ponds were stocked with postlarvae of Litopenaeus vannamei, the major farmed shrimp species in Korea, on July 10, 2007, and cultured for 90 days with no water exchange. The stocking density of the postlarvae (B.W. 0.0015 g) was $272\;ind./m^2$, which is eight times higher than in traditional pond culture in Korea. At harvest, the total production of ponds 1 and 2 was 1,362kg ($2.48\;kg/m^2$) and 1,282 kg ($2.33\;kg/m^2$), respectively. This is 20~22 times higher than the mean farmed shrimp production ($0.112\;kg/m^2$) in Korea and about eight times higher than in traditional ponds with a good harvest. Although there was no water exchange throughout the culture period, the mean concentrations of unionized ammonia and nitrite-nitrogen were as low as 0.038 and 6.0 mg/L, respectively. The feed conversion rate (FCR) was 1.38, which is 20~45% lower than that of traditional pond cultures. The high efficiency of the diet in this study is thought to be due to a well-managed feeding strategy and well-developed bioflocs used as diet additions for the shrimp. The final body weight of the shrimp at harvest was low (12.2~12.5 g), compared with that of traditional pond culture. This may have resulted from the combination of a short culture period, high density of shrimp, and low temperature. This study suggests that a super-intensive shrimp pond culture method using biofloc technology with no water exchange can minimize viral transmission via water exchange, reduce coastal pollution, and enhance shrimp production.

• Asian-Australasian Journal of Animal Sciences
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• 제22권8호
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• pp.1202-1208
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• 2009

Synbiotics is the term used for a mixture of probiotics (live microbial feed additives that beneficially affects the host animal) and prebiotics (non-digestible food ingredients that beneficially affect the organism). This study investigated the effect of probiotics from anaerobic microflora with prebiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in weaning pigs. 150 pigs with an initial BW of 6.80${\pm}$0.32 kg (20 d of age) were randomly assigned to 5 dietary treatments as follows: i) US, basal diet+0.15% antibiotics (0.05% oxytetracycline 200 and 0.10% tiamulin 38 g), ii) BS, basal diet+0.2% synbiotics (probiotics from bacteria), iii) YS, basal diet+0.2% synbiotics (probiotics from yeast), iv) MS, basal diet+0.2% synbiotics (probiotics from mold), v) CS, basal diet+0.2% synbiotics (from compounds of bacteria, yeast and mold). The probiotics were contained in $10^{9}$ cfu/ml, $10^{5}$ cfu/ml and $10^{3}$ tfu/ml of bacteria, yeast and molds, respectively. The same prebiotics (mannan oligosaccharide, lactose, sodium acetate and ammonium citrate) was used for all the synbiotics. Pigs were housed individually for a 16-day experimental period. Growth performance showed no significant difference between antibiotic treatments and synbiotics-added treatments. The BS treatment showed higher (p<0.05) dry matter (DM) and nitrogen digestibility while ether extract and crude fiber digestibility were not affected by the dietary treatment. Also, the BS treatment decreased (p<0.05) fecal ammonia and amine gas emissions. Hydrogen sulfide concentration was also decreased (p<0.05) in BS, YS and MS treatments compared to other treatments. Moreover, all the synbioticsadded treatments increased fecal acetic acid concentration while the CS treatment had lower propionic acid concentration than the US treatment (p<0.05) gas emissions but decreased in fecal propionate gas emissions. Total fecal bacteria and Escherichia coli populations did not differ significantly among the treatments, while the Shigella counts were decreased (p<0.05) in synbiotics-included treatment. Fecal bacteria population was higher in the YS treatment than other treatments (p<0.05). The BS treatment had higher yeast concentration than YS, MS and CS treatments, while US treatment had higher mold concentrations than MS treatment (p<0.05). Therefore, the results of the present study suggest that synbiotics are as effective as antibiotics on growth performance, nutrient digestibility and fecal microflora composition in weaning pigs. Additionally, synbiotics from anaerobic microflora can decrease fecal noxious gas emission and synbiotics can substitute for antibiotics in weaning pigs.

• Asian-Australasian Journal of Animal Sciences
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• 제25권7호
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• pp.962-970
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• 2012

This study aimed to investigate the effects of ruminal infusion of garlic oil (GO) on fermentation dynamics, fatty acid (FA) profile, and abundance of bacteria involved in biohydrogenation in the rumen. Six wethers fitted with ruminal fistula were assigned to two groups for cross-over design with a 14-d interval. Each 30-d experimental period consisted of a 27-d adaptation and a 3-d sample collection. Goats were fed a basal diet without (control) or with GO ruminal infusion (0.8 g/d). Ruminal contents collected before (0 h) and at 2, 4, 6, 8, and 10 h after morning feeding were used for fermentation analysis, and 0 h samples were further used for FA determination and DNA extraction. Garlic oil had no influence on dry matter intakes of concentrate and hay. During ruminal fermentation, GO had no effects on total VFA concentration and individual VFA molar proportions, whereas GO increased the concentrations of ammonia nitrogen and microbial crude protein (p<0.05). Compared with control, GO group took a longer time for total VFA concentration and propionate molar proportion to reach their respective maxima after morning feeding. The ratio of acetate to propionate in control reduced sharply after morning feeding, whereas it remained relatively stable in GO group. Fatty acid analysis showed that GO reduced saturated FA proportion (p<0.05), while increasing the proportions of C18, t11-18:1 (TVA), c9,t11-conjugated linoleic acid (c9,t11-CLA), t10,c12-CLA, and polyunsaturated FA (p<0.05). The values of TVA/(c9,t11-CLA+TVA) and C18:0/(TVA+C18:0) were reduced by GO (p<0.05). Real-time PCR showed that GO tended to reduce Butyrivibrio proteoclasticus abundance (p = 0.058), whereas GO had no effect on total abundance of the Butyrivibrio group bacteria. A low correlation was found between B. proteoclasticus abundance and C18:0/(TVA+C18:0) (p = 0.910). The changes of fermentation over time suggested a role of GO in delaying the fermentation process and maintaining a relatively modest change of ruminal environment. The inhibitory effects of GO on the final step of biohydrogenation may be related to its antibacterial activity against B. proteoclasticus and other unknown bacteria involved.

• Asian-Australasian Journal of Animal Sciences
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• 제24권10호
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• pp.1456-1463
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• 2011

A total of 629 Duroc${\times}$Landrace${\times}$Large White crossbred pigs were utilized in three experiments (Exp. 1, 222 pigs weighing $25.6{\pm}2.0\;kg$ BW; Exp. 2, 216 pigs weighing 5$6.2{\pm}4.3\;kg$ BW; Exp. 3, 191 pigs weighing $86.4{\pm}4.6\;kg$ BW) conducted to determine the effects of fermented potato pulp on performance, nutrient digestibility, carcass traits and plasma parameters in growingfinishing pigs. Each experiment lasted 28 d. The pigs were assigned to one of two corn-soybean meal-based diets containing 0 or 5% fermented potato pulp. The inclusion of fermented potato pulp increased weight gain (p<0.05) in experiments 1 and 2 and increased feed intake (p<0.05) in experiment 2. Feed conversion was improved (p<0.05) in experiment 2 and showed a tendency to improve (p<0.10) in experiments 1 and 3 when pigs were fed fermented potato pulp. Fermented potato pulp increased (p<0.05) dry matter digestibility in experiments 1 and 3 and energy digestibility in experiment 2. Feeding fermented potato pulp decreased plasma urea nitrogen (p<0.05) and alanine aminotransferase (p<0.05) in experiments 1 and 2, while plasma aspartate aminotransferase was decreased (p<0.05) in experiment 3. Dietary fermented potato pulp did not affect the carcass characteristics of finishing pigs. Feeding fermented potato pulp reduced (p<0.05) fecal ammonia concentration in all three experiments. In conclusion, feeding growing-finishing pigs diets containing 5% fermented potato pulp improved weight gain and feed conversion without any detrimental effects on carcass traits. The improvements in pig performance appeared to be mediated by improvements in nutrient digestibility.