• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.527-539
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• 2010

This study was conducted to determine the effect of probiotics as an alternative for antibiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in growing piglets. A total of 96 piglets ($22.5{\pm}1.3$kg average body weight) were allotted to 3 different treatment groups and replicated 4 times with 8 piglets per replicate in randomized complete block design. Treatments were T1) (Control, basal diet+0.2% antibiotics), T2) 0.2% probiotics complex and T3) 0.3% Bacillus probiotics. During the whole experiment period, there were no differences (p>0.05) in average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency. However, digestibility of dry matter, crude protein, ether extract, nitrogen free extract and crude ash were showed higher in probiotics groups (T2 and T3) than those of control. In noxious gas emission, ammonia, amine, hydrogen sulfide and mercaptan were significantly (p<0.05) reduced in T2 and T3 treatments compared to those in control. Moisture content of feces was not significantly different among treatments. The colony forming units (CFU) of total bacteria, E. coli and thermoduric bacteria in feces were significantly different among treatments. The CFU of total bacteria, E. coli and thermoduric bacteria in T3 treatment were reduced by feeding probiotics B. From this study, we suggest that probiotics A and B are likely able to improve the growth performance and nutrients digestibility, reduce noxious gas emission and change the fecal microbial composition in growing piglets.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.4
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• pp.322-331
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• 2017

This study was conducted to evaluate the changes of pH, dry matter digestibility (DMD), $NH_3-N$ concentrate, gas production and volatile fatty acid (VFA) through in vitro fermentation by adding horse feces to various juice pomaces fermented with Bacillus, yeast and lactic acid bacteria. The pH range of fermented fluid with juice pomaces was 6.4-7.1, indicating that the digestion by microbial fermentation was normal. Juice pomaces adopted will be helpfully used to assist with digestion by microbes in intestines because approximately $10^9CFU/m{\ell}$ microbes were grown after 48 hours in fermented fluid. DMD rate gradually increased from 12 hours. It was 39.19% in pomaces of apple, 38.22% in grape, 37.02% in carrot, 36.2% in citrus and 34.35% in mixture respectively after 48 hours. $NH_3-N$ concentrate was not changed significantly as it was maintained at $1.5mg/100m{\ell}$ level in the entire treatment group from beginning of fermentation until 12 hours, but increased rapidly from 24 hours. Amount of gas produced was lowest in the mixture and increased rapidly after 12 hours. Total VFA increased from 24 hours and was highest at 48 hours. It was suggested that dry matter digestion was processed while fermented juice pomaces kept proper pH during in vitro digestion, and cellulose degrading microorganisms could act actively in the caecum and colon of horses.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.559-568
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• 2003

This study was carried out to investigate the effect of probiotics on the performance, nutrients digestibility, noxious gas emission and microflora population on the cecum of broilers. A total of 120 broilers, consisted of 4 treatments X 3 replicates X 10 broilers per replicates, were fed the experimental diets containing 0, 0.1, 0.3 and 0.5％ probiotics for 5 weeks. Broilers fed the diets containing 0.1 and 0.3％ probiotic had higher (p<0.05) body weight gain and feed conversion than those of the others from the 3rd to 4th week. Broilers fed 0.3％ probiotic had higher (p<0.05) body weight gain and feed conversion than those of the other levels from the 5th to 6th week. Broilers fed the diets containing 0.1% and 0.3％ probiotic had higher (p<0.05) body weight gain and feed conversion than those of the others from the 2nd to 6th week. Dry matter digestibility was significantly (p<0.05) improved with 0.3% probiotic. Emission of ammonia and sulfate hydrogen gas was significantly (p<0.05) decreased at 6th week. However, there was no (p<0.05) difference at the levels of 0, 0.1, 0.3 and 0.5% at the 4th weeks. There was an increase in the lactobacillus sp, but there was a decrease in the microflora population of coliforms in the cecum of broiler with 0.1% and 0.3% probiotics. These results indicated that the compound probiotics of 0.1${\sim}$0.3% were effective in the body weight gain, feed conversion, nutrients digestibility, noxious gas emission and microflora population on the cecum in broilers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.2
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• pp.119-127
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• 2021

The objective of this study was to evaluate effects of feeding methods on in vitro ruminal fermentation, total gas and methane production in Hanwoo steers. Six Hanwoo steers fitted with rumen cannula (430 ± 21 kg of body weight) were randomly assigned to one of three feeding systems: 1) feeding forage 1 hour after concentrate, 2) feeding concentrate 1 hour after forage, 3) feeding mixed ration. Rumen fluid sampled from each animals was incubated 24 hours with maize or timothy substrates in in vitro. Ruminal pH was increased in feeding method 2 or maize substrate than that of other methods or timothy substrate (P < 0.001). The production of total volatile fatty acid, acetate, propionate, butyrate, and valerate were increased when steers fed diets using feeding method 1 or rumen fluid was incubated with maize substrate (P < 0.001). Increased production of total gas and methane was observed in feeding method 1 and maize substrate compared to those of other methods or timothy substrate (P < 0.001). Due to the inconsistent results between ruminal fermentation and gas production in this study, further research is required to estimate effects of feeding method on enteric fermentation and gas production in in vivo.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.225-231
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• 2002

Total 240 of ISA Brown layers were employed in this experiment to study the effects of single or mixed feeding of Lactobacillus and yeast on the performance and intestinal microflora of laying hens. They were randomly allocated to six dietary treatments; None(Control), Pichia farinosa(PF), Lactobacillus crispatus avihen1 (LCH), Lactobacillus vaginalis avihen1(LVH), LCH＋PF, and LVH＋PF. Viable microflora were added to meet 3${\times}$10$\^$6/ cfu PF and 10$\^$7/ cfu Lacrobacillus per g of feed. There were four replicates per treatment, and 10 birds per replicates. Laying performance was recorded for 10 weeks, followed by a metabolism trial during which nutrient utilization, pattern of intestinal microflora and fecal NH$\sub$3/ emission were examined. Egg production and daily egg mass of birds fed either single or mixed microorganisms were significantly higher than those of the control(P<0.05). Egg weight and feed intake were not statistically different among all treatments. However, feed conversion ratio tended to improve by the supplementation of microbes. Digestibility of crude protein, ether extract and crude ash tended to improve in Lactobacillus treatments, however, there were not statistically different. With regards to the number of intestinal microbes, number of anaerobes were increased in microbes feeding group. Eggshell quality of PF layers was significantly poorer than those of the other treatments. No consistent trend was found in Haugh Unit among all treatments. Fecal NH$\sub$3/ gas emission was significantly lower in LVH, LVH＋PF and LCH＋PF than the other treatments(P<0.05). From the result of this experiment, it could be concluded that single or mixed feeding of Lactobacillus and yeast improves the laying performance and decreases the fecal ammonia gas emission. No synergic effect was found when both microbes were mixed and fed to the layers.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.24-29
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• 2013

In the present study, the effects of prebiotics and prebiotics+probiotics on intestinal microflora and fermentation products were evaluated in a pig in vitro fermentation model. The substrates used in this study were iso-malto oligosaccharide (IMO), partially digested chicory-inulin (CI), raffinose (RA), and cyclodextrin (CD) as prebiotics and Lactobacillus reiteri as probiotics. For a pig in vitro fermentation, the experimental diet for growing pigs was predigested using digestive enzymes secreted by small intestine and this hydrolyzed diet was mixed with a buffer solution containing 5% fresh swine feces. The mixture was then incubated with either prebiotics or prebiotics+probiotics for 24 h. Samples were taken at 24 h, and viable counts of microflora, gas, pH, volatile organic compounds (VOCs) and short-chain fatty acid (SCFA) were analyzed. The viable count of Enterobacteriaceae was significantly decreased (p<0.001) in all treatments containing prebiotics and prebiotics+probiotics when compared to the control. However, the number of lactic acid bacteria increased in the prebiotics and prebiotics+probiotics treatment. The pH values in the fermentation fluid decreased in all treatments when compared to the control, and their effects were greater in the prebiotics+probiotics group than prebiotics group. Fermentation with prebiotics resulted in a reduction in malodorous compounds such as ammonia, hydrogen sulfide and skatole when compared to the prebiotics+probiotics group. Short-chain fatty acid production was also higher for treatment with prebiotics+probiotics than treatment with prebiotics. In conclusion, the results of this study demonstrated that fermentation with prebiotics was effective in reducing the formation of malodorous compounds and prebiotics+probiotics was effective in increasing lactic acid bacteria and SCFA and reducing the pH. Moreover, further studies will be needed to determine whether the results observed in the in vitro model would occur in pigs that ingest these prebiotics or probiotics.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.383-392
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• 2006

This study was conducted to investigate the effects of a supplemented mixture of herbs (artemisia, eucommia ulmoids and houttuynia cordata) on the growth performance, nutrient utilization, blood characteristics, microflora population and diarrhea frequency in weanling pigs. Eighty-four pigs were randomly allotted into one of the four dietary treatments, each of which had 3 replicates. Experimental diets were prepared by adding (0.0, 0.5, 1.0 and 2.0%) a mixture of artemisia, eucommia ulmoids and houttuynia cordata to a commercial feed, and were given to pigs for 42 days. Daily feed intake was significantly increased in the groups supplemented with the mixture at 1.0% group and 2.0% group. Digestibility was significantly increased in 1.0% for protein and ether extract, and in 1.0% group and 2.0% group for NFE. Total bacillus and lactobacillus sp. were significantly (p<0.05) improved in 1.0% group and 2.0% group, respectively. Glucose concentrations of serum increased significantly (p<0.05) in 0.5% group and 1.0% group, and HDL increased significantly (p<0.05) in 1.0% group and 2.0% group. Diarrhea decreased by treatments except control (p<0.05). It is concluded that pigs fed the diet supplemented with 1.0% mixture of herbs can improve daily body weight gain, feed efficiency, nutrient utilizations and diarrhea frequency in pigs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.244-245
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• 2003

고체나 액체 추진로켓에 비하여 하이브리드 추진 시스템은 작동조건의 안정성과 안전함등의 많은 장점을 가지고 있다. HTPB와 같은 고체연료는 제작 및 저장, 운송 그리고 장착상의 안정성을 가지고 있으며 하이브리드 로켓의 고체연료로의 산화제의 유입을 제어하면서 추력의 변화와 엔진내부의 연소중단과 재 점화를 용이하게 할 수 있다. 이러한 이유로 인하여 하이브리드 엔진은 좀 더 경제적인 장치로 기대를 모으고 있다. 그러나, 기존의 하이브리드 로켓 엔진은 고체 추진 로켓에 비하여 낮은 연료 regression 율과 연소효율을 가지는 단점이 있다. 이러한 단점을 해결하고 요구되어지는 추력값과 연료유량을 증가시키기 위하여 고체연료의 표면적을 증가시킬 필요가 있다. 기존의 하이브리드 엔진에서는 연료 그레인에 다수의 연소포트를 만들어 표면적을 증가시켰으나 이는 비 활용 공간의 증가와 추진제의 질량 및 체적분율의 상당한 감소를 초래한다. 지난 수십년간에 걸쳐 하이브리드 엔진에서 연료의 regression 특성 및 엔진 성능 향상을 위한 연구가 계속되어 왔으며 최근에 엔진의 체적 규제를 경감시키고 연료의 regression율을 향상시키기 위하여 선회유동을 이용하는 하이브리드 로켓 엔진들이 제안되고 있다. 이러한 선회유동을 가지는 하이브리드 로켓은 고체연료 그레인에 대하여 평행하게 유입되는 기존의 하이브리드 로켓에 비하여 고체연료 벽면에서의 대류열전달이 현저하게 증가하게 되어 아주 높은 고체연료의 regression율을 얻을 수 있는 이점이 있다. 선회유동 하이브리드 로켓의 연소과정은 고체 연료의 열분해과정, 대류 열전달, 난류 혼합, 난류와 화학반응의 상호작용, soot의 생성 및 산화과정, soot 입자 및 연소가스에 의한 복사 열전달, 연소장과 음향장의 상호작용 등의 복잡한 물리적 과정을 포함하고 있다. 이러한 물리적 과정 중 난류연소, 고체연료 벽면 근방에서의 대류 열전달 및 연소과정에서 생성되는 soot 입자로부터의 복사 열전달, 그리고 고체연료 열 분해시 표면반응들은 고체연료의 regression율에 큰 영향을 미친다. 특히 고체연료의 난류화염면의 위치와 폭, 그리고 비 예혼합 난류화염장에서 생성되는 soot의 체적분율의 예측은 난류연소모델, 열전달 모델, 그리고 regression율 모델에 의해 크게 영향을 받기 때문에 수치모델의 예측 능력 향상시키기 위하여 이러한 물리적 과정을 정확히 모델링해야 할 필요가 있다. 특히 vortex hybrid rocket내의 난류연소과정은 아래와 같은 Laminar Flamelet Model에 의해 모델링 하였다. 상세 화학반응 과정을 고려한 혼합분율 공간에서의 화염편의 화학종 및 에너지 보존 방정식은 다음과 같다. 화염편 방정식과 혼합분률과 scalar dissipation rate의 관계식을 이용하여 혼합분률과 scalar dissipation rate에 따른 모든 reactive scalar들을 구하게 된다. 이러한 화염편 방정식들을 mixture fraction space에서 이산화시켜서 얻은 비선형 대수방정식은 TWOPNT(Grcar, 1992)로 계산돼 flamelet Library에 저장되게 된다. 저장된 laminar flamelet library를 이용하여 난류화염장의 열역학 상태량 평균치는 presumed PDF approach에 의해 구해진다. 본 연구에서는 강한 선회유동을 가지는 Hybrid Rocket 연소장내의 난류와 화학반응의 상호작용을 분석하기 위하여 Laminar Flamelet Model, 화학평형모델, 그리고 Eddy Dissipation Model을 이용한 수치해석결과를 체계적으로 비교하였다. 또한 Laminar Flamelet Model과 state-of-art 물리모델들을 이용하여 선회 유동을 갖는 하이브리드 로켓 엔진의 연소 및 Soot 생성 및 산화과정을 살펴보았으며 복사 열전달이 고체 연료 표면의 regression율에 미치는 영향도 살펴보았다. 특히 swirl강도, 산화제의 유입위치 그리고 선회유동의 형성방식이 하이브리드 로켓의 연소특성 및 regression rate에 미치는 영향을 상세히 해석하였다.

• Journal of Life Science
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• v.29 no.2
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• pp.223-230
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• 2019

Ozone is a gaseous molecule able to kill microorganisms, such as yeast, fungi, bacteria, and protozoa. However, ozone gas is unstable and cannot be used easily. In order to utilize ozone properly and efficiently, plant oil can be employed. Ozone reacts with C-C double bonds of fatty acids, converting to ozonized oil. In this reaction, ozonide is produced within fatty acids and the resulting ozonized oil has various biological functions. In this study, we showed that ozonized oil has antimicrobial activity against fungi and bacteria. To test the antimicrobial activity of ozonized oil, we produced ozonized olive oil. Ozonized olive oil was applied to Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Antimicrobial activity was assayed using the disk diffusion method following the National Committee for Clinical Laboratory Standards. Minimal inhibitory concentrations (MIC) were 0.25 mg for S. aureus, 0.5 mg for S. epidermidis, 3.0 mg for P. aeruginosa, and 1.0 mg for E. coli. Gram positive bacteria were more susceptible than Gram negative bacteria. We compared growth inhibition zones against S. aureus and MRSA, showing that the ozonized olive oil was more effective on MRSA than S. aureus. Furthermore, the ozonized olive oil killed C. albicans within an hour. These data suggested that ozonized olive oil could be an alternative drug for MRSA infection and could be utilized as a potent antimicrobial and antifungal substance.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.967-974
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• 2009

The effects of Opuntia ficus-indica var. saboten powder on the growth of lactic acid bacteria (LAB) were investigated in order to explore the possibility of manufacturing fermented milk containing the powder. Differences in pH, acidity, LAB counts, viscosity, and sensory evaluation were measured. Also the effects of dietary supplementation on the growth of piglets were evaluated by feeding fermented milks containing 0.1%, 0.2%, 0.5%, and 1.0% Opuntia ficus-indica var. saboten powder. Levels of pH, titratable acidity, viable LAB counts and viscosity were significantly different by the addition of the powder. When fermented milks containg 0.1%, 0.2%, 0.5% and 1.0% Opuntia ficus-indica var. saboten powder were kept at $4^{\circ}C$ for 30 days, viable LAB counts remained high after 30 days of storage. The effects of dietary supplementation of 0.2% Opuntia ficus-indica var. saboten fermented milk were investigated by examining piglet growth rate and fecal ammonia gas release. The piglets were fed 100g/herd of the fermented milk for 14 days. Average daily body weight gain was significantly (p<0.05) improved (110%) with dietary supplementation of the fermented milk, compared to a control group. More over, fecal ammonia gas emissions were reduced by dietary supplementation of the Opuntia ficus-indica var. saboten fermented milk. Sensory evaluation results showed that the samples containing 0.1% and 0.2% Opuntia ficus-indica var. saboten powder had the most parameters similar to those of the control.