The present study estimated rumen fermentation characteristics and greenhouse gas emissions of different forages. Alfalfa, timothy, tall fescue, Italian ryegrass, and rice straw as the main forage sources for Hanwoo were used in the present study. Crude protein was highest in alfalfa but lowest in rice straw (p<0.05). Ether extract was higher in alfalfa and Italian ryegrass than in the other forages (p<0.05). Crude ash was highest in rice straw but lowest in tall fescue (p<0.05). Neutral detergent fiber was highest in tall fescue but lowest in alfalfa (p<0.05). Acid detergent fiber was highest in Italian ryegrass and rice straw but lowest in alfalfa (p<0.05). In vitro digestibilities of dry matter (DMD) and neutral detergent fiber (NDFD) were highest in timothy but lowest in rice straw (p<0.05). Rumen pH was highest (p<0.05) in alfalfa, while ammonia-N was higher (p<0.05) in alfalfa and Italian ryegrass than in the other forages. Total volatile fatty acid was highest (p<0.05) in timothy, while acetate and propionate were highest (p<0.05) in alfalfa and rice straw, respectively. Acetate to propionate ratio was higher (p<0.05) in alfalfa, timothy, and Italian ryegrass than in rice straw. Rice straw had lowest total gas (mL) (p<0.05) but highest its per DMD and NDFD. Rice straw had higher (p<0.05) CO2 (per DMD and NDFD) compared to alfalfa (per DMD and NDFD), timothy (per DMD and NDFD), tall fescue (per NDFD), and Italian ryegrass (per DMD). Again, rice straw had higher (p<0.05) CH4 (per DMD and NDFD) compared to timothy (per DMD and NDFD) and tall fescue (per NDFD). Therefore, this study indicates that timothy has a higher nutrient digestibility and volatile fatty acid in the rumen leading to a reduction of greenhouse gas emission.

한우에게 급여하는 사료 내 에너지원의 종류에 따라 반추위 미생물의 아미노산 조성에 차이가 있는지를 조사하고자 본 연구를 수행하였다. 국내 한우 비육우 사육에 주로 이용되는 에너지원 사료인 옥수수(T1), 생미강(T2), 소맥(T3) 그리고 소맥피(T4)로 반추위 환경과 유사한 연속식 배양기를 이용하여 72시간까지 배양을 진행하였다. 배양이 진행되는 동안 6시간 간격으로 배양액의 발효 성상을 확인하였으며 pH, NH3-N이 일정하게 유지되는 것을 확인하였으며, 배양 종료 시점인 72시간대에 미생물체 단백질 합성량(MPS), 미생물의 아미노산 조성 및 미생물 균총 변화를 분석하였다. 배양액의 pH는 모든 처리구에서 배양 기간동안 5.5~7.0을 유지하였다. Total VFA 농도는 T1이 23.13 mM으로 가장 낮았고, T4가 29.93 mM으로 가장 높았다(p<0.05). A (acetate) :P (propionate) 비율은 T1이 1.48로 가장 낮았으며, T4가 2.81로 가장 높게 나타났다 (p<0.05). Butyrate는 T1이 2.37 mM으로 가장 낮았으며, T2, T3 그리고 T4는 4.37~4.58 mM으로 차이가 없었다(p<0.05). MPS는 T2 (332.5 mg/L)와 T3 (320.2 mg/L)가 높았고 T1 (137.5 mg/L)와 T4 (154.2 mg/L)로 낮게 나타났다(p<0.05). DGGE band 분석결과 모든 처리구는 57.5 % 이하의 유사도가 나타났다. 미생물의 총 아미노산 함량은 T1 (31.59 %)과 T3 (31.33 %)가 가장 높았으며, T2 (20.09 %)가 가장 낮았다 (p<0.05). 이는 급여된 사료 내 총 아미노산 함량과 반대되는 결과로 나타났다. 따라서, 본 연구에서 한우 급여 에너지원 사료에 따른 반추위 내 미생물 발효 특성과 미생물체 단백질 합성량이 미생물 군집에 영향을 미치며 이에 따라 미생물의 총 아미노산 함량에 영향을 미친다는 것을 확인하였다.

본 연구의 목표는 S. boulardii 유래 세포벽 추출물 (CWSB)의 첨가가 반추위 발효에 미치는 영향을 평가하는 것이다. 본 연구의 in vitro 발효 실험은 CWSB의 첨가용 량이 다른 2개의 실험으로 구성되었다. 실험 1에서는 대 조구(CON, 시험사료)와 CWSB0.05(시험사료+CWSB 0.5g/kg 첨가), CWSB0.075(시험사료+CWSB 0.75g/kg 첨 가)의 처리구로 구성되었고, 실험 2의 처리구는 대조구 (CON, 시험사료)와 CWSB0.5(시험사료+ CWSB 5g/kg 첨 가), CWSB1.0(시험사료+CWSB 10g/kg 첨가)의 처리구로 구성되었다. In vitro 배양 이후 3, 6, 12, 24, 48h 동안 발 생한 가스 발생량 및 48h 배양 이후 발효 성상을 분석하 였다. 실험 1에서는 CWSB0.05 처리구에서 유의적으로 높 았던 Vmax(p<0.01)를 제외한 모든 반추위 발효성상에서 처 리구간 유의적 차이가 관찰되지 않았고, 이에 따라 사료 내 0.5%, 1%의 고용량 첨가 수준을 설정한 실험 2를 수행 하였다. 실험 2에서의 CWSB1.0 처리구는 대조구에 비해 총 VFA 발생량이 유의적으로 높았으나 전체 배양시간 내 가스 발생량 및 건물 소화율, 섬유소 소화율은 대조구와 유의적인 차이를 나타내지 않았다. 본 연구 결과를 종합 해 볼 때, CWSB의 첨가수준은 0.5% 이상에서 반추위 발 효 개선효과를 나타낼 것으로 추정된다.

반추위 미생물체 단백질의 아미노산 조성이 한우의 에 너지원 사료에 따라 차이가 있는지를 조사하고자 본 연구 가 수행되었다. 본 실험은 국내 한우 비육우 사육에 주로 이용되는 에너지원 사료인 옥수수(T1), 생미강(T2), 소맥 (T3), 소맥피(T4)를 이용하여 in vitro 반추위 발효실험을 진행하여 발효 24시간 후 배양액의 발효 성상, 미생물체 단백질 합성량(MPS), 미생물의 아미노산 조성 및 미생물 균총 변화를 분석하였다. 배양액의 pH는 T4가 6.02로 다 른 처리구들에 비해서 가장 높았으며, T1은 4.84로 가장 낮았다(p<0.05). Total VFA 농도는 T2가 96.80mM로 다른 처리구들에 비해서 가장 높았고, T1이 53.35mM로 가장 낮았다(p<0.05). 미생물체 단백질 합성량은 T3가 222.50g/L로 다른 처리구들에 비해서 높았으며(p<0.05), T1과 T4는 유의적인 차이는 없었지만 T1이 가장 낮았다. DGGE band 분석결과 모든 처리구는 57.5% 이하의 유사도를 나타내었으며, 급여되는 사료에 따라서 미생물 군집 이 다르게 나타났다. 미생물 내 총 아미노산 함량은 T3와 T4가 다른 처리구보다 높았다(p<0.05). 미생물의 아미노산 조성 중 대부분의 필수 아미노산은 T4가 다른 처리구들에 비해서 낮았다. 하지만 methionine은 다른 필수 아미노산 과 다르게 T4에서 가장 높았다(p<0.05). 곡류 사료 위주의 급여 시 결핍되기 쉬운 lysine은 모든 처리구에서 미생물 의 아미노산 조성이 8.05~8.98%의 범위에 있었다. 따라서, 본 연구에서 반추 가축 급여 에너지 사료원에 따른 반추 위 내 미생물 발효특성과 미생물 군집의 차이가 미생물의 아미노산 조성을 변화시킨다는 것을 확인하였다.

The present study was conducted to examine the effect of soybean silage as a crude protein supplement for corn silage in the diet of Hanwoo steers. The first experiment was conducted to evaluate the effect of replacing corn silage with soybean silage at different levels on rumen fermentation characteristics in vitro. Commercially-purchased corn silage was replaced with 0, 4, 8, or 12% of soybean silage. Half gram of the substrate was added to 50 mL of buffer and rumen fluid from Hanwoo cows, and then incubated at 39°C for 0, 3, 6, 12, 24, and 48 h. At 24 h, the pH of the control (corn silage only) was lower (p<0.05) than that of soybeansupplemented silages, and the pH numerically increased along with increasing proportions of soybean silage. Other rumen parameters, including gas production, ammonia nitrogen, and total volatile fatty acids, were variable. However, they tended to increase with increasing proportions of soybean silage. In the second experiment, 60 Hanwoo steers were allocated to one of three dietary treatments, namely, CON (concentrate with Italian ryegrass), CS (concentrate with corn silage), CS4% (concentrate with corn silage and 4% of soybean silage). Animals were offered experimental diets for 110 days during the growing period and then finished with typified beef diets that were commercially available to evaluate the effect of soybean silage on animal performance and meat quality. With the soybean silage, the weight gain and feed efficiency of the animal were more significant than those of the other treatments during the growing period (p<0.05). However, the dietary treatments had little effect on meat quality except for meat color. In conclusion, corn silage mixed with soybean silage even at a lower level provided a greater ruminal environment and animal performances, particularly with increased carcass weight and feed efficiency during growing period.

본 연구는 조사료 원료인 마늘 껍질의 사료적 가치와 메탄 발생량을 조사하기 위해 in vitro 발효 실험을 수행하였다. Garlic husk를 제외하고 국내에서 널리 사용되는 4가지 조사료 원료(Oat hay, Annual ryegrass, Timothy, Tall fescue)를 실험의 처리구로 구성하였다. In vitro 48 시간 발효 후 건물 소화율, 섬유소 소화율, 암모니아태 질소, 휘발성 지방산, pH, 메탄 발생량을 평가하였다. 가스 발생량은 3, 6, 9, 12, 24, 36 및 48 시간에 각각 측정되었다. 최종 가스 발생량에서 Oat hay가 유의적으로 가장 높았다(p<0.01). Garlic husk는 처리구 중 가장 높은 메탄 발생량을 나타내었다(p<0.01). Garlic husk의 건물 소화율은 Oat hay보다 유의적으로 낮았지만 Annual ryegrass, Timothy, Tall fescue보다 높았다(p<0.01). 섬유소 소화율은 Annual ryegrass에서 가장 낮았다(p<0.01). 총 휘발성 지방산 생성량은 Oat hay에서 가장 높았고(p<0.01), Garlic husk, Timothy, Tall fescue는 유사하였다. 본 연구의 in vitro 발효 성상과 메탄 발생량을 고려할 때, Garlic husk는 국내 주요 조사료를 대체할 영양적 가치를 포함하고 있으나 메탄 저감 효과는 미미할 것으로 추정된다.

This in vitro study investigated the enhancement of rumen bacterial adhesion on a substrate to increase the digestibility of rice straw in Hanwoo cattle. The rice straw was pretreated with enzymes, probiotics, or ammonia, and the effects on the enhancement of bacterial adhesion and fiber degradation were analyzed using in vitro rumen fermentation. Enzyme treatment included spraying of cellulase and xylanase at 40 and 120 U per g of rice straw, respectively; Saccharomyces cerevisiae culture of 1.0×107 CFU was sprayed as a probiotic treatment per gram of rice straw; ammonia was sprayed at 0.3% per gram of rice straw. Following enzyme treatment, Fibrobacter succinogenes formed a higher adhesion colony than the control group (7.26±0.03 and 8.43±0.20) after 6h and 12h of in vitro culture (p<0.05), respectively. Attachment of Ruminococcus flavefaciens also increased following enzyme treatment (p<0.05) after 6 and 12 h compared to that of the control (5.18±0.06 and 6.60±0.15); and R. albus attachment showed a significant increase compared to that of the control (5.94±0.15) after 6 h of incubation (p<0.05). Probiotic treatment increased attachment of F. succinogenes in comparison with untreated rice straw after 6 h and 12 h of fermentation (p<0.05); R. flavefaciens attachment showed an increase only after 6 h of culture (p<0.05); R. albus was not affected. Attachment of F. succinogenes, R. flavefaciens, and R. albus increased with ammonia treatment after 6 h and 12 h (p<0.05). Dry matter digestibility was higher after the enzyme treatment (3.45±0.21 and 7.04±0.09) than in the control group(1.85±0.08 and 3.94±0.04) after 6 and 12 h of in vitro culture (p<0.05), respectively. It was also higher than that of untreated rice straw after probiotic and ammonia treatments (p<0.05). There was an increase in the enhancement levels of bacterial adhesion depending on the type of fibrolytic bacteria following enzyme, probiotic, and ammonia treatment. These treatments improved digestibility. This enhancement is considered to be greater following enzyme and ammonia treatments than with probiotics.

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.

In this study, the effect of forage sources in the total mixed ration (TMR) on in vitro goat rumen fermentation was investigated. Rice straw (RS), Italian ryegrass (IRG), timothy (TIM), and alfalfa (ALF) were used as forage sources. Each forage source was mixed with a commercial goat concentrate diet in the ratio of 1:1. Total 4 TMR were prepared. Rumen simulated in vitro fermentation using goat rumen fluid collected from the slaughterhouse was conducted until 72 th . For fermentation parameters, gas production (GP), volatile fatty acids (VFAs), and ammonia nitrogen (NH3-N) were examined. All assays were performed at 24 th , 48 th , and 72 th h of incubation individually. Contents of crude protein and non-fibrous carbohydrate were greater in the order of RS < IRG < TIM < ALF. Significant treatment effects were found in valerate and NH3-N at 24 th h of incubation (p<0.05). ALF showed the greatest contents of them and RS was the lowest. At 48 th incubation, a significant effect was detected at GP (p<0.05) and RS was greater than others. However, GP of RS was lower than others at 72 th . Significant effects on Total VFA, butyrate, and valerate productions were found at 72 th h of incubation (p<0.05). ALF showed the greatest production. Methane production from all treatments was not significantly different for each incubation time (p>0.05). The present study provided primary information on how goat rumen fermentation responds to different nutrient contents and forage sources of TMR. And the information could be used for the design or optimizing economical diet formulation for goats.

Diets different in crude protein (CP) and undegraded intake protein (UIP) contents were offered to sheep in a metabolism study to describe their effects on nutrient digestibility and nitrogen (N) metabolism. Six Corriedale sheep (body weight=56.2±2.3 kg) were divided in random within a Latin square design (replicated) to 1 of 3 diets: 1) a low-CP diet (LP; 12.2% CP with 35.1% UIP), 2) high CP with low UIP diet (HPLU; 14.9% CP with 33.7% UIP), and 3) high CP with high UIP diet (HPHU; 15.5% CP with 45.8% UIP). High-protein dried distillers grain and soybean meal were the main CP sources for the adjustment of UIP:DIP in the diets. No significant differences were found in feed consumption and nutrient digestibility; however, a greater proportion of CP was digested in sheep fed the HPLU diet (69.4%; P=0.04). Although N intake was greater in sheep receiving HPLU and HPHU diets, loss of N through fecal or urinary route was not different among sheep, which resulted in the highest (12.7 g/d) and lowest N retention (7.40 g/d) in HPHU- and LP-fed sheep, respectively. In conclusion, although CP or UIP content had marginal effects on feed consumption and whole-tract digestibility of the majority of nutrients, with the increased CP and UIP levels in the diet, the efficiency of N utilization was improved with regard to increased N retention with minimal differences in N excretion, which is important from an economic and environmental standpoint.

This study was conducted to observe the effect of fiber digestion enhancement and inhibition factors on fibrolytic bacterial colony growth and fiber digestion in the rumen fermentation environment. In order to promote the fiber digestion, 0.2% NaOH of rice straw was used as a substrate in rumen in vitro fermentation. A 0.1% methylcellulose (MC) was added rumen in vitro culture with untreated rice straw to inhibit fiber digestion. When in vitro culture was performed using untreated rice straw as a substrate, all substrate adherent colonies and rumen suspended colonies of Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminococcus albus showed an increasing growth as incubation time progressed; however there were significantly more substrate-adherent colonies than rumen fluid floating colonies at all incubation times (p<0.05). Fiber substrate digestibility in in vitro rumen fermentation was significantly higher 0.2% NaOH treated rice straw than untreated substrate (p<0.05). In addition, substrate-adherent colonies of fibrolytic bacteria were significantly more in the NaOH-treated group than in the untreated group for F. succinogenes, R. flavefaciens, and R. albus (p<0.05). When untreated rice straw was added to an in vitro culture, with or without 0.1% MC, to create a rumen environment for inhibiting fiber digestion, substrate digestibility was significantly suppressed compared to that in the untreated group (p<0.05). Additionally, substrate-adherent colonies were significantly fewer in the addition of MC than in the untreated control group for F. succinogenes, R. flavefaciens and R. albus (p<0.05). The results indicate that surface-adherent colonies of bacteria decomposing fiber substrate are far more than rumen fluid floating colonies in the rumen fermentation environment, and the environmental factors of rumen fermentation give same associative effect on the fibrinolytic function of fiber bacteria and its ecological communities.

반추동물의 급여 단백질 효율성은 반추위 내 미생물 발효에 따른 우회단백질, 미생물체단백질, 사료 및 미생물체의 아미노산 구성 등에 의해 결정된다. 실험 1은 주요 단백질 사료원료 중 국내 한우 사육에 주로 이용되는 사료원료 15종[옥수수(남미), 옥수수(우크라이나), 단백피(국내), 단백피(중국1), 단백피(중국2), 대두박(국내), 대두박(미국), 대두박(브라질), DDGS(미국), 팜박(인도네시아), 채종박(캐나다), 루핀(미국), 미강(국 내), 주정박(국내), 타피오카(인도네시아)]의 반추위 내 단백질과 아미노산의 우회 수준을 측정하였다. 캐뉼라 장착 한우 암소를 이용하여 in situ 실험을 진행하였다. 우회 단백질 함량은 타피오카(인도네시아)에서 59.98%로 가장 높았다. 타피오카(인도네시아)는 총 우회 아미노산 함량이 73.73% 로 가장 높았으며, glutamic acid (Glu)와 alanine (Ala)이 72.17%, 75.23%로 가장 높았다. 실험 2에서는 실험 1과 같은 원료를 사용해 반추위 내 미생물 발효 특성에 따른 미생물체 아미노산 조성분석을 실시하였다. 실험 결과 채종박(캐나다)의 pH는 6.99 (p<0.05), 미생물 단백질 합성량은 326.53mg/100mL (p<0.05), NH3-N의 농도는 단백피(중국 1)가 48.20mg/100mL (p<0.05)로 높았다. 옥수수(우크라이나)의 총 VFA 농도는 97.92mM (p<0.05)이었다. 미생물의 총 아미노산 함량은 대두박(미국) 52.07%로 높았으며 아미노산 조성은 모든 시험 사료에서 Glu가 높았다. 따라서, 본 연구는 한우의 급여 단백질 사료원에 대한 반추위 내 우회단백질, 우회아미노산함량과 반추위 내 미생물 아미노산 조성에 대한 연구를 실시하였으며, 향후 한우 단백질 급여사료원에 대한 대사단백질(MP) 공급체계의 기초자료로 활용될 수 있을 것이다.

국제적으로 최근의 세계적인 축산 ICT 개발 추세는 음성, 맥박, 저작수, 호흡수, CCTV 영상인식 등 보다 다양하고 다중적ㆍ통합적인 센서기술을 접목하여 분만, 상해, 질병 감염, 발정, 반추 및 저작 등 가축의 중요한 생명ㆍ생산 활동을 판단하고 조기에 발견하는 연구들이 시도되고 있다. 이에 본 연구는 ICT 기술을 활용하여 농가 생산성 향상 방안의 일환으로 체류형 바이오캡슐 내 pH, 반추위 체온 및 활동성 센서를 활용한 생체정보를 수집하였고 도축등급과의 상관관계 여부를 파악하고자 수행하였다. 시험방법으로는 26개월령의 한우 거세우 10두를 공시하여 5개월간 바이오캡슐 자료들을 수집하였고 이후 도축하여 등급판정성적과의 연관성 여부를 분석하였다. 연구 결과 육량 등급과 관련이 있는 등심단면적, 등지방두께, 도체중과 생체형질인 반추위 pH, 체온 그리고 활동성과는 모두 정(+)의 상관을 보였다. 육질등급과 관련 있는 근내지방도 및 성숙도는 생체형질인 체온에서는 정(+)의 상관을, pH 및 활동성과는 부(-)의 상관을 나타낸 반면에, 조직감에 대하여 체온은 부(-)의 상관을, pH 및 활동성과 는 정(+)의 상관을 보였다. 특히, 활동성과 근내지방도간의 상관계수가 –0.65로 통계적 유의성을 보였는데 (p<0.05), 이러한 결과는 소의 활동성이 낮으면 근내지방도는 높아진다는 것을 제시하여 준다. 반면에 pH와 도체중 간의 상관계수는 0.50으로 나타나 정(+)의 상관을 보였다. 이는 반추위의 pH가 낮아지면 체중도 작아진다는 것으로 분석된다. 본 연구 결과를 확대하여 계절 및 시간대별 생체정보가 도축성적에 미치는 요인에 대하여 추가적인 분석이 필요하며, 이를 근거로 한우 생산성 향상을 위한 생체정보를 활용할 수 있는 정보를 제공해 줄 것으로 판단된다.

This study investigated the effects of silage additives on rumen fermentation characteristics of rye silage. Rye was harvested at ripening stage and treated with different additives in quadruplicate following: without additive (control), with either lactic acid bacteria inoculant (LAB), formic acid (FA), or Ca-formate (Ca-FA). Overall, ensiling characteristics of FA and Ca-FA silages contained 4-fold more (P<0.05) butyrate and 2-fold more (P<0.05) NH3-N concentration (% total nitrogen) than those of control and LAB silages. Cows fed LAB silage showed a diurnal trend with the highest values of propionate concentration compared to the control at 1, 2 and 3 hr after feeding. In contrast, FA and Ca-FA silages increased the proportion of butyrate significantly (P<0.05) at all sampling times compared to control and LAB silage. In conclusion, Forage rye treated with FA or Ca-FA showed different fermentation characteristics during ensilage and in the rumen compared to LAB silage. Further studies are needed to evaluate whether different fermentation characteristics in the rumen between LAB and FA silages had effect on partitioning of nutrients between milk production and body tissue.

This study was to evaluate the feed value of whole crop rice silage (WCRS) and to investigate a suitable ratio of the WCRS and concentrate by an analysis of rumen fermentation. A total of 6 treatments were used according to WCRS: concentrate ratio on in vitro rumen fermentation: T1 (100:0), T2 (60:40), T3 (40:60), T4 (20:80), T5 (10:90), and T6 (0:100). The ruminal pH, total gas emission, ammonia nitrogen, and volatile fatty acid (VFA) were determined as fermentation parameters. Total nutrients digestibility trial was conducted by 4 treatments according to WCRS: concentrate ratio at 40:60 (W40), 20:80 (W20), and 10:90 (W10), respectively. Feed value was analyzed according to AOAC (2019) and nutrient digestibility was calculated based on NRC (2001). The levels of crude protein (CP), crude fat, and neutral detergent fiber of the WCRS were 12.29%, 1.67%, and 59.79%, respectively. It was found to be 51.49% as a result of predicting the total digestible nutrient of WCRS using the NRC (2001) model. In vitro rumen fermentation, T4, T5, and T6 treatments showed a greater gas emission and total VFA concentration compared with other treatments (p<0.05). Acetate and acetate to propionate ratio of T4, T5, and T6 were significantly higher than other treatments (p<0.05). There was a significant difference in the level of propionate and butyrate according to the WCRS: concentrate ratio (p<0.05). The digestibility of dry matter and CP was significantly lower in W40 than in other treatments (p<0.05); however, there was no difference in W20 and W10. In conclusion, the 20:80 (WCRS: concentrate) is beneficial for stabilizing the rumen that does not inhibit rumen fermentation and nutrient digestion. This ratio might have a positive effect on the economics of farms as a valuable feed.

This study was conducted to research on the efficacy of chemical treatment as an effective method for reducing mycotoxin in rice straw silage. As a chemical treatment method, ammonia and sodium hydroxid were treated at 4% level of rice straws contaminated with mycotoxin, and the effects of silage storage on fungal toxin reduction, fermentation quality, and fiber digestion were evaluated. Aflatoxin B1, B2, G1, G2 and fumonisin B1, B2 as well as deoxynivalenol were not detected in all experimental groups, and ochratoxin A and zearalenone were detected. Ochratoxin A was detected lower in the chemical treatment than control (41.23 g / kg) (p<0.05). Zearalenone showed lower results in sodium hydroxide treatment (297.44 μg / kg) than control (600.33 μg / kg) and ammonia treatment (376.00 μg / kg) (p<0.05). The pH of rice straw silage was the lowest in ammonia treatment and the highest in sodium hydroxide treatment (p<0.05). The lactic acid contents of control and ammonia treatments were similar, but sodium hydroxide treatment was the lowest (p<0.05). Propionic acid was higher in the control than in the chemical treatments (p<0.05), and showed similar contents in the ammonia and sodium hydroxide treatment. Both the rumen microbial degradation rate of NDF and ADF showed the highest in sodium hydroxide treatment, followed by ammonia treatment, and the control showed the lowest level (p<0.05). Therefore, the results of this study are demonstrated to have a good effect on the treatment of ammonia and sodium hydroxide to reduce the mycotoxins and increase the rumen microbial degradation rate in the rice straw silage. Sodium hydroxide treatment was more effective in reducing mycotoxins and improving fiber degradation rate than ammonia treatment, but it is thought to have an inefficient effect on silage fermentation in rice straw silage.

In in vitro fermentation studies, feed samples can either be included in the in vitro rumen medium using filter bags or can be directly dispersed. The objective of this study was to investigate the effects of different pore sizes of filter bags on the rumen fermentation characteristics in an in vitro system. Corn, soybean meal, and timothy were ground to pass through a 1.0-mm screen and were formulated in the ratio of 70:7:23 based on DM, respectively. The formulated experimental diet (2g/DM) was put in F57 filter bags and R510 nylon bags (Ankom®) which pore sizes were 25 and 50 μm, respectively. An in vitro study was conducted to determine the rumen fermentation characteristics for 3, 6, 12, 24, and 48 h and rumen microbial community at 48 h of incubation. A significantly higher production of gas was observed in the R510 bags than in F57 at all the incubation times (p<0.01). IVDMD (p<0.01) and IVNDFD (p<0.01) were significantly higher, whereas pH (p<0.01) and NH3-N (p<0.01) were lower when R510 bags were used. In the VFA composition, acetate and butyrate were significantly higher (p<0.01) in R510 bags, and propionate and total VFA concentration did not differ (p=0.55 and 0.25, respectively) between F57 and R510 bags. The log copy numbers of bacteria and protozoa did not differ (p=0.69 and 0.94, respectively) between F57 and R510 bags, whereas those of fungi were significantly higher in R510 than in F57 bags (p<0.01). Therefore, the use of R510 may reflect actual rumen fermentation characteristics more precisely than those of F57 because increased gas production, nutrient digestibility and acetate, butyrate proportion were founded in R510.

메탄가스는 주요 온실가스 중 하나로 반추동물의 장내발효를 통해 발생하며, 이러한 경로의 메탄가스는 대한민국 축산부문 총 온실가스 발생량의 40% 이상을 차지한다. 이런 이유로 많은 연구자들은 반추동물에서 발생하는 메탄생성량을 줄이기 위한 시도를 계속해 왔다. 본 연구는 반추동물의 메탄발생량을 측정하기 위해 호흡대사챔버를 개발하고 호흡대사챔버의 정확성을 검증하기 위해 실시하였다. 호흡대사챔버는 25.4 m3 크기로 스테인리 스 플레이트로 내부를 완전히 밀폐하였다. 직경 Φ100의 공기 유입관과 배출관을 설치하였고, 공기 배출관에 에어모터를 설치하여 내부공기를 제거함과 동시에 유입관을 통해 배출된 만큼의 공기가 외부에서 유입되도록 하였다. 챔버 내 메탄가스 회수기능을 검증하기 위해 메탄표준가스 5L를 각 챔버에 주입하여 균일하게 확산시킨 후, 챔버 내부의 공기를 900 L/min의 속도로 제거하였다. 제거된 공기의 메탄가스 농도를 연속적으로 측정하여 주입된 메탄가스와 비교함으로써 회수율을 평가하였다. 챔버 내 표준가스는 평균 100분에 완전히 제거되었으며, 메탄가스의 회수율은 평균 109 ± 6.7%로 측정되었다. 호흡대사챔버의 실제 이용성을 평가하기 위해, 평균체중 581.9 ± 33.8 kg 의 한우 거세우 4두에게 비육후기 배합사료 9 kg과 볏짚 1 kg을 급여하며 메탄발생량을 측정하였다. 한우의 장내발효에 의한 메탄발생량은 평균 236.4 ± 105.44 L/day로 측정되었다. 본 연구에서 개발·검증한 호흡대사챔버는 국내 한우의 장내발효 메탄가스발생량 측정 시험에 적용 가능할 것이다.