• Title/Summary/Keyword: 소화가스

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Effects of Antibiotics, Copper Sulfate and Probiotics Supplementation on Performance and Ammonia Emission from Slurry in Growing Pigs (사료에 대한 항생제, 황산동 및 생균제 첨가가 육성돈의 생산성 및 슬러리의 암모니아 발생에 미치는 영향)

  • Han, Y.K.;Shin, H.T.
    • Journal of Animal Science and Technology
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    • v.47 no.4
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    • pp.537-546
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    • 2005
  • An experiment was conducted to determine the effect of supplementation of chlortetracycline (CTC,110ppm), copper sulfate(Cu, 125ppm) and two levels of probiotics(Prob I, 0.04%, Prob II, 0.1%), Bacillus licheniformis and Bacillus subtilis) on growth performance, nutrient digestibility and manure characteristics in growing pigs. A total of 50 pigs that averaged 20.78$\pm$0.35kg BW and 50$\pm$2.3d age were allocated in a randomized block design with two pigs per pen and 5 pens per treatment. Pigs and feeders were weighed 10-days interval for the 40-d trials to determine ADG, ADFI and feed:gain ratio(F:G). Average daily gain, feed intake, feed/gain and nutrient digestibility were not improved(P>0.10) by the supplementation of CTC, Cu and two levels of probiotics. There were significant(P<0.05) Cu effects on digestibility of crude protein, and probiotics effects on digestibilities on organic matter, crude protein and energy between first 20 days and subsequent 20 days. Fecal concentrations of copper were highly increased(P<0.001) by the copper supplementation. Total bacteria and coliform counts were not altered by the supplementation of CTC, Cu and two levels of probiotics. Ammonia emission from slurry, measured during first 3 weeks, was reduced (P<0.001) in pigs fed diet with 125 ppm copper from copper sulfate. Results indicate that CTC, Cu and Probiotics supplementation had a little or not positive effect on grower pig performance under sound environmental conditions. Further studies may be warranted to investigate the effects of dietary copper-either reduced or in combination with dietary ammonia control agents-on the ammonia emission characteristics of swine manure.

A Study on the Application of Bushings Fire Prevent Structure to Prevent Fire Spread of Transformer (변압기의 화재확산 방지를 위한 부싱 방화구조체 적용에 관한 연구)

  • Kim, Do-Hyun;Cho, Nam-Wook;Yoon, Choung-Ho;Park, Pil-Yong;Park, Keun-Sung
    • Fire Science and Engineering
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    • v.31 no.5
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    • pp.53-62
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    • 2017
  • Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

A study on inspection methods for waste treatment facilities(I): Derivation of impact factor and mass·energy balance in waste treatment facilities (폐기물처리시설의 세부검사방법 마련연구(I): 공정별 주요인자 도출 및 물질·에너지수지 산정)

  • Pul-Eip Lee;Eunhye Kwon;Jun-Ik Son;Jun-Gu Kang;Taewan Jeon;Dong-Jin Lee
    • Journal of the Korea Organic Resources Recycling Association
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    • v.31 no.1
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    • pp.69-84
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    • 2023
  • Despite the continuous installation and regular inspection of waste treatment facilities, complaints about excessive incineration and illegal dumping stench continue to occur at on-site treatment facilities. In addition, field surveys were conducted on the waste treatment facilities currently in operation (6 type) to understand the waste treatment process for each field, to grasp the main operating factors applied to the inspection. In addition, we calculated the material·energy balance for each main process and confirmed the proper operation of the waste disposal facility. As a result of the site survey, in the case of heat treatment facilities such as incineration, cement kilns, and incineration heat recovery facilities, the main factors are maintenance of the temperature of the incinerator required for incineration and treatment of the generated air pollutants, and in the case of landfill facilities Retaining wall stability, closed landfill leachate and emission control emerged as major factors. In the case of sterilization and crushing facilities, the most important factor is whether or not sterilization is possible (apobacterium inspection).In the case of food distribution waste treatment facilities, retention time and odor control during fermentation (digestion, decomposed) are major factors. Calculation results of material balance and energy resin for each waste treatment facility In the case of incineration facilities, it was confirmed that the amount of flooring materials generated is about 14 % and the amount of scattering materials is about 3 % of the amount of waste input, and that the facility is being operated properly. In addition, among foodwaste facilities, in the case of an anaerobic digestion facility, the amount of biogas generated relative to the amount of inflow is about 17 %, and the biogas conversion efficiency is about 81 %, in the case of composting facility, about 11 % composting of the inflow waste was produced, and it was comfirmend that all were properly operated. As a result, in order to improve the inspection method for waste treatment facilities, it is necessary not only to accumulate quantitative standards for detailed inspection methods, but also to collect operational data for one year at the time of regular inspections of each facility, Grasping the flow and judging whether or not the treatment facility is properly operated. It is then determined that the operation and management efficiency of the treatment facility will increase.

Effects of Dietary Germanium Biotite in Weaned, Growing and Finishing Pigs (이유자돈, 육성돈 및 비육돈에 있어 게르마늄흑운모의 급여 효과)

  • Kwon, O.S.;Kim, I.H.;Hong, J.W.;Lee, S.H.;Jung, Y.K.;Min, B.J.;Lee, W.B.;Shon, K.S.
    • Journal of Animal Science and Technology
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    • v.45 no.3
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    • pp.355-368
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    • 2003
  • In Exp. 1, this study was conducted to determine the effect of dietary germanium biotite on growth performance and nutrient digestibility in nursery pigs. A total of sixty crossbred pigs (initial body weight 15.09$\pm$0.18kg) were used in this experiment. This study was carried out for 28 days. The five treatments were control (CON; basal diet), GB0.1 (basal diet + germanium biotite 0.1%), GB0.3 (basal diet + germanium biotite 0.3%), GB0.6 (basal diet + germanium biotite 0.6%) and GB1.0 (basal diet + germanium biotite 1.0%). For overall period, ADG and Gain/feed were not significantly different among the treatments. In Exp. 2, a study was conducted to evaluate the effect of germanium biotite as a substitute for antibiotics in growing pigs. A total of fifty five crossbred pigs (initial body weight 32.47$\pm$0.9kg) were used in this experiment. The three treatments were negative control (NC: basal diet without antibiotic), positive control (PC: basal diet + 200ppm CTC) and GB0.3 (basal diet + germanium biotite 0.3%). Pigs fed PC (17%, 385 vs 451 g/d) and GB0.3 (14%, 385 vs 438 g/d) diets grew faster(P<0.05) than pigs fed NC diet. Pigs fed PC and GB0.3 diets resulted higher(P<0.05) ADFI than pigs fed CON diet. However, pigs fed GB0.3 diet had improved gain/feed compared to pigs fed NC diet(P<0.05). Apparent digestibility of DM and N by pigs fed PC and GB0.3 diets were greater(P<0.05) than those by pigs fed NC diet. In Exp. 3, a study was conducted to determine the effect of dietary germanium biotite on growth performance, plasma characteristics, backfat thickness and fecal ammonia gas concentration in finishing pigs. A total of seventy-two finishing pigs (initial body weight 78.56$\pm$1.32kg) were used in this experiment. The treatments included 1) Control (CON; basal diet) 2) GB1.0 (basal diet + germanium biotite 1.0%), 3) GB3.0 (basal diet + germanium biotite 3.0%). Pigs fed GB1.0 diet grew faster than pigs fed CON diet and GB0.3 diet (P<0.05). Also, pigs fed CON diet showed higher(p<0.05) ADFI than pigs fed GB3.0 diet. Pigs fed GB diets had improved gain/feed compared to pigs fed CON diet(P<0.05). Total?and VLDL concentrations in plasma of pigs fed GB diets treatments were significantly decreased compared to those in pig fed CON diet(P<0.05). However, HDL-cholesterol concentration in plasma of the pig was significantly increased compared to those in pigs fed CON diet (P<0.05). Pigs fed CON diet exerted higher(P<0.05) backfat thickness than pigs fed GB1.0 (5.4%, 27.19 vs 25.71mm) and GB3.0 (16.1%, 27.19 vs 22.81mm) diets. Feces from CON treatment were higher in fecal ammonia gas concentration than faces from pigs fed GB1.0 (64.1%, 17.00 vs 6.10mg/kg)and GB3.0 (61.8%, 17.00 vs 6.50mg/kg) treatments(P<0.05). In conclusion, the results suggest that the dietary addition of germanium biotite into diets for nursery pigs did not affect growth performance. The results also suggest the possibility of germanium biotite to replace antibiotic in diets for growing pigs. In finishing pigs, dietary supplementation of germanium biotite was an effective means for improving growth performance and for decreasing Total-and LDL+VLDL-plasma cholesterols, backfat and fecal ammonia gas concentration.

Effects of Halogenated Compounds on in vitro Fermentation Characteristics in the Rumen and Methane Emissions (할로겐 화합물의 첨가가 반추위 발효성상과 메탄생성에 미치는 영향)

  • Hwang, Hee-Soon;Ok, Ji-Un;Lee, Shin-Ja;Chu, Gyo-Moon;Kim, Kyoung-Hoon;Oh, Young-Kyoon;Lee, Sang-Suk;Lee, Sung-Sill
    • Journal of Life Science
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    • v.22 no.9
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    • pp.1187-1193
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    • 2012
  • This study was conducted to evaluate effects of halogenated compounds on in vitro rumen fermentation characteristics and methane emissions. A fistulated Holstein cow of 650 kg body weight was used as a donor of rumen fluid. Five kinds of halogenated compounds (bromochloromethane (BCM), 2-bromoethane sulfonic acid (BES), 3-bromopropanesulfonic acid (BPS), chloroform (CLF), and pyromellitic diimide (PMDI) known to inhibit methyl-coenzyme M reductase activity were added to an in vitro fermentation incubated with rumen fluid. The microbial population including bacteria, protozoa, and fungi were enumerated, and gas production including methane and fermentation characteristics were observed in vitro. The pH values ranged from 6.25 to 6.72 in all the treatments, and these showed a similar level at 48 hr. The total gas production in the treatments showed a similar pattern with C at 48 hr, whereas methane production in the treatments was lower (p<0.05) than C. Concentrations of total volatile fatty acids (VFAs) and propionic acid were higher (p<0.05) in the treatments than in C at 12 hr. Therefore, halogenated compounds (BCM, BES, BPS, CLF, and PMDI) inhibited in vitro methane emissions by inhibiting methanogens in the rumen. Further studies on safety are needed.

The Respiratory and Hemodynamic Effects of Prone Position According to the Level of PEEP in a Dog Acute Lung Injury Model (잡종견 급성폐손상 모델에서 Prone position 시행시 PEEP 수준에 따른 호흡 및 혈류역학적 효과)

  • Lim, Chae-Man;Chin, Jae-Yong;Koh, Youn-Suck;Shim, Tae-Sun;Lee, Sang-Do;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.1
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    • pp.140-152
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    • 1998
  • Background: Prone position improves oxygenation in patients with ARDS probably by reducing shunt Reduction of shunt in prone position is thought to be effected by lowering of the critical opening pressure (COP) of the dorsal lung because the pleural pressure becomes less positive in prone position compared to supine position. It can then be assumed that prone position would bring about greater improvement in oxygenation when PEEP applied in supine position is just beneath COP than when PEEP is above COP. Hemodynamically, prone position is expected to attenuate the lifting of cardiac fossa induced by PEEP. Based on these backgrounds, we investigated whether the effect of prone position on oxygenation differs in magnitude according to the level of PEEP applied in supine position, and whether impaired cardiac output in supine position by PEEP can be restored in prone position. Methods: In seven mongrel dogs, $PaO_2/F_1O_2$(P/F) was measured in supine position and at prone position 30 min. Cardiac output (CO), stroke volume (SV), pulse rate (PR), and pulmonary artery occlusion pressure (PAOP) were measured in supine position, at prone position 5 min, and at prone position 30 min. After ARDS was established with warmed saline lavage(P/F ratio $134{\pm}72$ mm Hg), inflection point was measured by constant flow method($6.6{\pm}1.4cm$ $H_2O$), and the above variables were measured in supine and prone positions under the application of Low PEEP($5.0{\pm}1.2cm$ $H_2O$), and Optimal PEEP($9.0{\pm}1.2cm$ $H_2O$)(2 cm $H_2O$ below and above the inflection point, respectively) consecutively. Results : P/F ratio in supine position was $195{\pm}112$ mm Hg at Low PEEP and $466{\pm}63$ mm Hg at Optimal PEEP(p=0.003). Net increase of P/F ratio at prone position 30 min, however, was far greater at Low PEEP($205{\pm}90$ mm Hg) than at Optimal PEEP($33{\pm}33$ mm Hg)(p=0.009). Compared to CO in supine position at Optimal PEEP($2.4{\pm}0.5$ L/min), CO in prone improved to $3.4{\pm}0.6$ L/min at prone position 5 min (p=0.0180) and $3.6{\pm}0.7$ L/min at prone position 30 min (p=0.0180). Improvement in CO was attributable to the increase in SV: $14{\pm}2$ ml in supine position, $20{\pm}2$ ml at prone position 5 min (p=0.0180), and $21{\pm}2$ ml at prone position 30 min (p=0.0180), but not to change in PR or PAOP. When the dogs were turned to supine position again, MAP ($92{\pm}23$ mm Hg, p=0.009), CO ($2.4{\pm}0.5$ L/min, p=0.0277) and SV ($14{\pm}1$ ml, p=0.0277) were all decreased compared to prone position 30 min. Conclusion: Prone position in a dog with saline-lavaged acute lung injury appeared to augment the effect of relatively low PEEP on oxygenation, and also attenuate the adverse hemodynamic effect of relatively high PEEP. These findings suggest that a PEEP lower than Optimal PEEP can be adopted in prone position to achieve the goal of alveolar recruitment in ARDS avoiding the hemodynamic complications of a higher PEEP at the same time.

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Effect of Byproducts Supplementation by Partically Replacing Soybean Meal to a Total Mixed Ration on Rumen Fermentation Characteristics In Vitro (대두박 대체 부산물 위주의 TMR 사료가 반추위 내 미생물의 In Vitro 발효특성에 미치는 영향)

  • Bae, Gui Seck;Kim, Eun Joong;Song, Tae Ho;Song, Tae Hwa;Park, Tae Il;Choi, Nag Jin;Kwon, Chan Ho;Chang, Moon Baek
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.34 no.2
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    • pp.129-140
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    • 2014
  • This study was performed to evaluate the effects of replacing basic total mixed ration (TMR) with fermented soybean curd, Artemisia princeps Pampanini cv. Sajabal, and spent coffee grounds by-product on rumen microbial fermentation in vitro. Soybean in the basic TMR diet (control) was replaced by the following 9 treatments (3 replicates): maximum amounts of soybean curd (SC); fermented SC (FSC); 3, 5, and 10% FSC + fermented A. princeps Pampanini cv. Sajabal (1:1, DM basis, FSCS); and 3, 5, 10% FSC + fermented coffee meal (1:1, DM basis, FSCC) of soybean. FSC, FSCS, and FSCC were fermented using Lactobacillus acidophilus ATCC 496, Lactobacillus fermentum ATCC 1493, Lactobacillus plantarum KCTC 1048, and Lactobacillus casei IFO 3533. Replacing dairy cow TMR with FSC treatment led to a pH value of 6 after 8 h of incubation-the lowest value measured (p<0.05), and FSCS and FSCC treatments were higher than SC and FSC treatment after 6 h (p<0.05). Gas production was higher in response to 3% FSC and FSCC treatments than the control after 4-10 h. Dry matter digestibility was increased 0-12 h after FSC treatment (p<0.05) and was the highest after 24 h of 10% FSCS treatment. $NH_3-N$ concentration was the lowest after 24 h of FSC treatment (p<0.05). Microbial protein content increased in response to treatments that had been fermented by the Lactobacillus spp. compared to control and SC treatments (p<0.05). The total concentration of volatile fatty acids (VFAs) was increased after 6-12 h of FSC treatment (p<0.05), while the highest acetate proportion was observed 24 h after 5% and 10% FSCS treatments. The FSC of propionate proportion was increased for 0-10 h compared with among treatments (p<0.05). The highest acetate in the propionate ration was observed after 12 h of SC treatment and the lowest with FSCS 3% treatment after 24 h. Methane ($CH_4$) emulsion was lower with A. princeps Pampanini cv. Sajabal and spent coffee grounds treatments than with the control, SC, and FSC treatments. These experiments were designed to replace the by-products of dairy cow TMR with SC, FSC, FSCS, and FSCC to improve TMR quality. Condensed tannins contained in FSCS and FSCC treatments, which reduced $CH_4$ emulsion in vitro, decreased rumen microbial fermentation during the early incubation time. Therefore, future experiments are required to develop a rumen continuous culture system and an in vivo test to optimize the percentages of FSC, FSCS, and FSCC in the TMR diet of the dairy cows.

Effects of Terpenoids-Rich Plant Extracts on Ruminal-fermentation and Methane Production (Terpenoid 함유 식물 추출물의 첨가가 반추위 발효와 메탄 발생에 미치는 영향)

  • Hwang, Hee-Soon;Ha, Dong-Uk;Lee, Su-Kyoung;Lee, Il-Dong;Lee, Shin-Ja;Lee, Sung-Sill
    • Korean Journal of Organic Agriculture
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    • v.21 no.4
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    • pp.629-646
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    • 2013
  • This study was conducted to investigate effects of terpenoids-rich plant extracts (TRPE) on the in vitro ruminal fermentation characteristics and methane production. The ruminal fluid was collected from a cannulated Hanwoo cow fed concentrate and timothy in the ratio of 6 to 4. The TRPE as Mint (Mentha arvensis var. piperascens), Pine (Pinus densiflora), Japan cedar (Cryptomeria japonica), Sichuan pepper (Zanthoxylum piperitum), Hinoki cypress (Chamaecyparis obtuse) and Japanese black pine (Pinus thunbergii) were used in this study. The 15 mL of mixture, contains McDougall buffer and rumen fluid in the ratio of 2 to 1. The mixture was dispensed anaerobically 50 mL serum bottles and it is contained 0.3 g timothy substrate and 5% TRPE. The bottles were incubated at $39^{\circ}C$ for 3, 6, 9, 12, 24, 48 and 72 hours. The pH value decrease by increased incubation times and the pH values at all times were significantly (p<0.05) higher in treatments than in control. The digestibility of dry matter at 3 hours was significantly (p<0.05) higher in mint treatment than in control. Productions of total gas and carbon dioxide at before 12 hours was significantly lower (p<0.05) in treatments than in control. The methane production at 24 hours was significantly (p<0.05) lower in treatments than in control. The concentrations of acetic acid and propionic acid at 24 hours were significantly higher (p<0.05) in mint and pine treatments than in control. In conclusion, the terpenoid-rich plant extracts were shown to decreased methane emission and without adversely affected ruminal fermentation. Therefore, the terpenoid-rich plant extracts as mint and pine were shown to decreased methane production and it has potential possibility for ruminal fermentations.

가금에서 분리된 유산균의 생리적 특성 및 급여효과

  • 김상호
    • Proceedings of the Korea Society of Poultry Science Conference
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    • 2002.11a
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    • pp.64-84
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    • 2002
  • These studies were conducted to evaluate the Properties of lactic acid Producing bacteria(LAB), isolated from broiler and laying hens cecum and select the optimum strains to improve the performance, environment of poultry house, immunity, and intestinal microflora of broiler and laying hens. In experiment I , 23 LAB strains were isolated from broiler and laying hens cecum as a colony form. Six strains were selected by acid tolerance, bile salt tolerance, viability, enzyme release, antagonism, and antibiotics susceptibility. In Experiment II, selected LABs from Ex. 1 were conducted to investigate the effects of feeding various Lactobacillus on performance, nutrients digestibility, intestinal microflora, villi development and observation of epithelium surface, blood chemicals and fecal noxious gas of broiler chicks. One thousand eighty one day old broiler chicks were fed into Lactobacillus crispatus avibrol(LCB), Lactobacillus reuteri avibro2(LRB), Lactobacillus crispatus avihen1(LCH), and Lactobacillus vaginalis avihen2(LVH) at the level of 10$^4$ and 10$\^$7/cfu/g diet. Weight gam of chicks fed Lactobacillus tended to increase from the first week and was higher from 50 to 100g in Lactobacillus treatments than control. Feed intake and feed conversion were not statistically different of all treatments. Dry Matter digestibility of Lactobacillus treatments was prone to improve compared to that of control, but was not significantly different. Protein and Ca digestibility were also tended to improve in Lactobacillus treatments relative that of control. Lactobacillus treatments showed improved tendency in crude ash and fat compared to those of control, whereas phosphorus digestibility was not consistency. Nutrients digestibilities of bird fed LCH were superior to those of other treatments, It showed significantly higher in Ca and P digestibility than control(P〈0.05). Total Lactobacillus spp. of birds fed various Lactobacillus was significantly higher in illeum for five weeks(P〈0.05), but was not different at cecum. Yeast was thought to be not completely attached to intestinal lumen for one week. However, total number of yeast was significantly increased in cecum and illeum of three weeks old chicks (P〈0.05). The number of anaerobes exhibited to tendency the increase in Lactobacillus treatments from one week old of age at both ileum and cecum.

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Effects of Single or Mixed Feeding of Lactobacillus and Yeast on Performance, Nutrient Digestibility, Intestinal Microflora, and Fecal NH$_{3}$ Gas Emission in Laying Hens (유산균과 효모의 단독 및 혼합 급여가 산란계의 생산성, 영양소 소화율, 장내미생물 변화 및 분의 암모니아 발생량에 미치는 영향)

  • 김상호;유동조;박수영;이상진;치철환;성창근;류경선
    • 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.