• Animal Bioscience
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• 제37권2_spc호
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• pp.370-384
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• 2024

Rumen microbiota play a central role in the digestive process of ruminants. Their remarkable ability to break down complex plant fibers and proteins, converting them into essential organic compounds that provide animals with energy and nutrition. Research on rumen microbiota not only contributes to improving animal production performance and enhancing feed utilization efficiency but also holds the potential to reduce methane emissions and environmental impact. Nevertheless, studies on rumen microbiota face numerous challenges, including complexity, difficulties in cultivation, and obstacles in functional analysis. This review provides an overview of microbial species involved in the degradation of macromolecules, the fermentation processes, and methane production in the rumen, all based on cultivation methods. Additionally, the review introduces the applications, advantages, and limitations of emerging omics technologies such as metagenomics, meta-transcriptomics, metaproteomics, and metabolomics, in investigating the functionality of rumen microbiota. Finally, the article offers a forward-looking perspective on the new horizons and technologies in the field of rumen microbiota functional research. These emerging technologies, with continuous refinement and mutual complementation, have deepened our understanding of rumen microbiota functionality, thereby enabling effective manipulation of the rumen microbial community.

• 유기물자원화
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• 제1권1호
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• pp.103-113
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• 1993

우리나라에서 년간 3,367만톤(1991년) 배출되는 생활쓰레기의 28% 이상이 주방폐기물로 통칭되는 음식찌꺼기, 채소류등으로 구성되는데 수분함량이 75~85%로 높고 발열량 낮아 혐기성 소화에 의한 처리법은 폐기물의 안정화 및 메탄가스 회수를 통한 효율적인 자원화가 가능하여 매우 실용적인 것으로 고려된다. 그러나, 주방폐기물은 셀룰로즈, 단백질등의 복잡한 고분자 고형물질들로 구성되어 있어 혐기성 소화시 가수분해반응이 율속단계로 인식되고 있으며, 이로 인한 유기물 부하율이 작고 반응조 용적이 커져 경제적이지 못한 것으로 알려져 있다. 따라서, 본 연구에서는 셀룰로즈 등의 고분자물질의 가수분해 반응에 활성이 뛰어난 rumen 미생물을 이용하여 주방폐기물의 혐기성 소화의 효율을 증진시키기 위한 연구가 600 mL의 회분식반응조에서 수행되었다. 주방폐기물의 가수분해 및 산생성 반응에 대한 중온산생성균과 rumen 미생물의 산생성반응 효율을 비교하였으며, rumen 미생물을 이용한 산형성 반응에서 pH, 온도, 고형물 농도등 환경인자의 영향을 평가하였다. Rumen 미생물을 이용한 주방폐기물의 산형성 반응에서 최종휘발산수율은 이론치의 약 95%에 해당하는 8.4meq/g VS를 보여 중온산형성균을 이용하였을 때와 비슷하였으나, 산생성반응의 속도는 중온산형성균을 이용했을 때 보다 약 2배 이상 빨랐다. Rumen 미생물을 이용한 주방폐기물의 산생성 반응에 대한 기질 농도의 영향에서는 TS 15%일 때 급격한 pH저하 및 비이온화된 VFA 등의 저해작용으로 휘발산수율은 TS 1%인 반응조에서의 절반이하의 값을 보여 유출수의 연속적인 희석이 중요한 인자임을 알 수 있었다. Rumen 미생물을 이용한 산생성 반응의 최적 pH 및 온도 범위는 각각 6.0~7.5, $35{\sim}45^{\circ}C$였다. 이상과 같은 결과로부터 rumen 미생물을 주방폐기물의 혐기성소화 공정에 이용할 경우 혐기성 반응의 율속단계로 고려되는 가수분해 및 산형성 반응의 속도를 증가 시킬 수 있어 반응조 용적 감소 및 유기물 부하 증가 등의 소화 효율향상이 가능함을 알 수 있었다.

• Journal of Animal Science and Technology
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• 제58권9호
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• pp.33.1-33.7
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• 2016

Background: The continuing growth of the ethanol industry has generated large amounts of various distillers grains co-products. These are characterized by a wide variation in chemical composition and ruminal degradability. Therefore, their precise formulation in the ruminant diet requires the systematic evaluation of their degradation profiles in the rumen. Methods: Three distillers grains plus soluble co-products (DDGS) namely, corn DDGS, high-protein corn DDGS (HP-DDGS), and wheat DDGS, were subjected to an in situ trial to determine the degradation kinetics of the dry matter (DM) and crude protein (CP). Soybean meal (SBM), a feed with highly degradable protein in the rumen, was included as the fourth feed. The four feeds were incubated in duplicate at each time point in the rumen of three ruminally cannulated Hanwoo cattle for 1, 2, 4, 6, 8, 12, 24, and 48 h. Results: Wheat DDGS had the highest filterable and soluble A fraction of its DM (37.2 %), but the lowest degradable B (49.5 %; P < 0.001) and an undegradable C fraction (13.3 %; P < 0.001). The filterable and soluble A fraction of CP was greatest with wheat DDGS, intermediate with corn DDGS, and lowest with HP-DDGS and SBM; however, the undegradable C fraction of CP was the greatest with HP-DDGS (41.2 %), intermediate with corn DDGS (2.7 %), and lowest with wheat DDGS and SMB (average 4.3 %). The degradation rate of degradable B fraction ($%\;h^{-1}$) was ranked from highest to lowest as follows for 1) DM: SBM (13.3), wheat DDGS (9.1), and corn DDGS and HP-DDGS (average 5.2); 2) CP: SBM (17.6), wheat DDGS (11.6), and corn DDGS and HP-DDGS (average 4.4). The in situ effective degradability of CP, assuming a passage rate of $0.06h^{-1}$, was the highest (P < 0.001) for SBM (73.9 %) and wheat DDGS (71.2 %), intermediate for corn DDGS (42.5 %), and the lowest for HP-DDGS (28.6 %), which suggests that corn DDGS and HP-DDGS are a good source of undegraded intake protein for ruminants. Conclusions: This study provided a comparative estimate of ruminal DM and CP degradation characteristics for three DDGS co-products and SBM, which might be useful for their inclusion in the diet according to the ruminally undegraded to degraded intake protein ratio.

• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.131-138
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• 2009

Among rumen microbes, bacteria play important roles in the biological degradation of plant fiber due to their large biomass and high activity. To maximize the utilization of fiber components such as cellulose and hemicellulose by ruminant animals, the ecology and functions of rumen bacteria should be understood in detail. Recent genome sequencing analyses of representative fibrolytic bacterial species revealed that the number and variety of enzymes for plant fiber digestion clearly differ between Fibrobacter succinogenes and Ruminococcus flavefaciens. Therefore, the mechanism of plant fiber digestion is also thought to differ between these two species. Ecology of individual fibrolytic bacterial species has been investigated using pure cultures and electron microscopy. Recent advances in molecular biology techniques complement the disadvantages of conventional techniques and allow accurate evaluation of the ecology of specific bacteria in mixed culture, even in situ and in vivo. Molecular monitoring of fibrolytic bacterial species in the rumen indicated the predominance of F. succinogenes. Nutritive interactions between fibrolytic and non-fibrolytic bacteria are important in maintaining and promoting fibrolytic activity, mainly in terms of crossfeeding of metabolites. Recent 16S rDNA-based analyses suggest that presently recognized fibrolytic species such as F. succinogenes and two Ruminococcus species with fibrolytic activity may represent only a small proportion of the total fibrolytic population and that uncultured bacteria may be responsible for fiber digestion in the rumen. Therefore, characterization of these unidentified bacteria is important to fully understand the physiology and ecology of fiber digestion. To achieve this, a combination of conventional and modern techniques could be useful.

• 한국초지조사료학회지
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• 제18권4호
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• pp.345-350
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• 1998

본 시험은 우리나라의 조사료자원 확대 방안을 모색하는 노력의 일환으로 대부분의 축산농가에서 조사료원으로 이용하고 있는 볏짚의 생육기별에 따른 사료가치를 구명하기 위하여 1998년 4월부터 동년 11월까지 우석대학교 부속 시험포장에서 수행하였으며 그 결과는 다음과 같다. 1. 볏짚의 생육기별 섬유소와 조회분 함량은 벼의 생육이 진행됨에 따라 증가하였으며, 조단백질과 조회분 함량은 감소하였다. NDF 함량은 큰 변화가 없었다. 황숙기 이후 hemicellulose 함량은 크게 감소하였고, cellulose 및 lignin 함량은 증가하였다. 2. 볏짚의 성숙기별 NDF의 반추위 분해율은 출수기때 가장 빨랐고, 유숙기부터는 비슷한 경향을 보였다. ADF의 반추위 분해율은 성숙기별에 따라 큰 변화를 나타내지 않았다. 따라서 볏짚의 성숙에 따른 화학적 조성분의 변화와 반추위 분해율을 종합해 볼 때, 출수기까지의 볏짚은 아직 목질화가 완성되지 않아 섬유질의 반추위 분해속도도 빨랐고, 그 이후의 볏짚은 사료적 가치가 급속히 낮아진다고 할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권5호
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• pp.752-757
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• 1999

Studies were made of digestion of timothy (Pheleum pretense) hay, tall fescue (Festuca elatior) hay, and rice (Oryza sativa) straw in pure cultures of rumen anaerobic fungus, Neocallimastix frontails MCH3. The fungus was inoculated on ground forages (1%, w/v) in an anaerobic medium and incubated at $39^{\circ}C$. Incubation was continued for 24, 48, 72 and 96 h. The losses of dry matter, xylose and glucose of forage during incubation were determined at the end of these incubation periods. Xylose and glucose were considered to be released from xylan and cellulose, respectively. The digested xylan to digested cellulose (X/C) ratios of the substrate were calculated. Xylanase and carboxymethyl cellulose (CMCase) of culture supernatant and residual substrate was measured at the same time. The X/C ratios in the cultures on timothy hay and rice straw were greater than 0.5 in the first 24-h incubation period. The values were smaller than 0.3 in tall fesque. The ratio of xylanase activity to that of CMCase in the first 24-h incubation period correlated well with the traits in X/C ratio. However xylanase activity was still superior to CMCase in the following incubation period (48 to 96 h), although the glucose (designated as cellulose) was more intensively digested than xylose (designated as xylan). The production of these polysaccharidases appeared to correlate with substrate cell-wall sugar composition, xylose to glucose ratios, at the beginning of fast growing period.

• Asian-Australasian Journal of Animal Sciences
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• 제16권7호
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• pp.979-982
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• 2003

Two rapeseed meal samples (Sample A, hybrid 5900 and sample B, double low rapeseed No.4) obtained from China and one Canola meal sample obtained from a local crushing plant in Canada were used to investigate the amino acid degradability of rapeseed/Canola meal in rumen and amino acid digestibility of ruminal incubation residues by precision-fed rooster bioassay. Results show that in ruminal incubation the degradation rate of non amino acid nitrogen in crude protein is higher than that for amino acid nitrogen in crude protein, the results also suggest that the degradation rate of amino acid nitrogen in Chinese rapeseed meal sample B was lower than that for Canadian Canola, but that in Chinese rapeseed meal sample A is much close to that for Canadian canola meal. For all amino acids the digestibility of the bypass or residual protein as measured by the precision-fed rooster bioassay tended to be lower for Chinese rapeseed meal sample A than for sample B or Canadian canola meal which had similar digestibility values. However following a calculation of total amino acid availability, involving the digestibility of amino acids in the rumen and rooster bioassay the results are less contradictory. Results indicated that in traditional roasting-expelling process, heat treatment, especially dry heat treatmeat could decrease amino acids degradability in rumen of rapeseed/canola meal, but also may decrease total availability of amino acids of rapeseed/canola meal.

• Asian-Australasian Journal of Animal Sciences
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• 제11권4호
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• pp.455-461
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• 1998

This study was proposed to investigate effects of inclusion of Chinese milk vetch silage (MVS) and rapeseed meal (RSM) on the growth and rumen fermentation of Hu-sheep. Fifty weanling lambs were randomly divided into five equal groups and offered ammoniated rice straw (ABRS) ad libitum along with 100 g concentrate (Trial 1). The animals in $T_0$, $T_1$, $T_2$, $T_3$ and $T_4$ group were respectively supplemented with MVS at levels of 0, 0, 7, 14 or 21% and with RSM at levels of 0, 15, 10, 5 or 0%. Daily gain of lambs was significantly (p<0.05) higher in $T_1$, $T_2$ and $T_3$ group than that in $T_0$ and $T_4$ group. Feed conversion ratio was greatly reduced in supplemented groups as compared with $T_0$ group. In trial 2, five sheep with rumen cannulae were used in a $5{\times}5$ Latin square design. The experimental treatments were as described in Trial 1, but without concentrate. The intake of AVRS was significantly (p<0.05) lower in $T_4$ group than that in $T_0$ group, and also significantly (p<0.05) lower than those in $T_1$ and $T_2$ group. Little difference among all treatments was found in 48h DM degradability of ABRS, MVS and RSM, and in rumen pH value and microbial protein concentration. Rumen concentrations of individual and total VFA tended to be higher in supplemented groups than those in $T_0$ group.These rusults suggest that supplementation with RSM or RSM plus MVS can effectively improve the performance of lambs, and may fail to influence markedly the rumen digestion of ABRS and rumen environments.

• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.35-42
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• 1998

Whole faba beans (WFB) were dry roasted at different temperatures (110, 130, $150^{\circ}C$) for 15, 30, 45 minutes to determine the optimal heating conditions of time and temperature to increase nutritional value. Ruminant degradation characteristics of crude protein (CP) of WFB were determined by the nylon bag incubation technique in dairy cows fed 60% hay and 40% concentrate. Measured characteristics of crude protein (CP) were soluble (washable) fraction (S), undegradable fraction (U), lag time (T0), potentially degradable fraction (D) and the rate of degradation (Kd) of insoluble but degradable fraction. Based on measured characteristics, percentage bypass crude protein (%BCP) and bypass crude protein (BCP in g/kg) were calculated. Degradability of CP was reduced by dry roasting (p < 0.01). S was reduced rapidly with increasing time and temperature, from 49.0% in the raw WFB (RWFB) to 26.3% in $150^{\circ}C/45$ min. D varied from 50.7% in RWFB to 73.7% in $150^{\circ}C/45^{\prime}$. U varied from 0% in $130^{\circ}C/45^{\prime}$, $150^{\circ}/30^{\prime}$ and $150^{\circ}/45^{\prime}$ to 0.66% in $110^{\circ}/45^{\prime}$ (0.24% for the RWFB). Lag time (T0) varied from 1.58 h in $130^{\circ}C/30^{\prime}$ to 2.40 h in $150^{\circ}C/45^{\prime}$ (1.87 h for RWFB). Kd varied from 24.2% in the $110^{\circ}C/30^{\prime}$ to 4.3% in $150^{\circ}C/45^{\prime}$ (21.4% for the RWFB). Kd was significantly reduced with time and temperature. All these effects resulted in increasing % BCP from 8.9% in the $110^{\circ}C/45^{\prime}$, 11.3% in the RWFB to 43.1% in the $150^{\circ}C/45$. Therefore BCP increased from 31.3 and 39.9 to 148.4 g/kg respectively. Both %BCP and BCP at $150^{\circ}C/45$ increased nearly 4 times over the raw faba beans. The effects of dry roasting temperature and time on %BCP and BCP seemed to be linear up to the highest values tested. Therefore no optimal dry roasting conditions of time and temperature could be determined at this stage. It was concluded that dry roasting was effective in shifting crude protein degradation from rumen to intestine to reduce unnecessary nitrogen (N) loss in the rumen. To determine the optimal treatment, the digestibility of each treatment should be measured in the next trial using mobile bags technique.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.534-541
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• 2009

The aim of this study was to evaluate the effects of gamma irradiation (${\gamma}$-irradiation) at doses of 15, 30 and 45 kGy on chemical composition, anti-nutritional factors, ruminal dry matter (DM) and crude protein (CP) degradibility, in vitro CP digestibility and to monitor the fate of true proteins of full-fat soybean (SB) in the rumen. Nylon bags of untreated or ${\gamma}$-irradiated SB were suspended in the rumens of three ruminally-fistulated bulls for up to 48 h and resulting data were fitted to a nonlinear degradation model to calculate degradation parameters of DM and CP. Proteins of untreated and treated SB bag residues were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Digestibility of rumen undegraded CP was estimated using the three-step in vitro procedure. The chemical composition of raw and irradiated soybeans was similar. Results showed that phytic acid in ${\gamma}$-irradiated SB at dose of 30 kGy was eliminated completely. The trypsin inhibitor activity of 15, 30 and 45 kGy ${\gamma}$-irradiated SB was decreased (p<0.01) by 18.4, 55.5 and 63.5%, respectively. From in sacco results, ${\gamma}$-irradiation decreased (p<0.05) the washout fractions of DM and CP at doses of 30 and 45 kGy, but increased (p<0.05) the potentially degradable fractions. Gamma irradiation at doses of 15, 30 and 45 kGy decreased (p<0.05) effective degradability of CP at a rumen outflow rate of 0.05 $h^{-1}$ by 4.4, 14.4 and 26.5%, respectively. On the contrary, digestibility of ruminally undegraded CP of irradiated SB at doses of 30 and 45 kGy was improved (p<0.05) by 12 and 28%, respectively. Electrophoretic analysis of untreated soybean proteins incubated in the rumen revealed that ${\beta}$-conglycinin subunits had disappeared at 2 h of incubation time, whereas the subunits of glycinin were more resistant to degradation until 16 h of incubation. From the SDS-PAGE patterns, acidic subunits of 15, 30 and 45 kGy ${\gamma}$-irradiated SB disappeared after 8, 8 and 16 h of incubation, respectively, while the basic subunits of glycinin were not degraded completely until 24, 48 and 48 h of incubation, respectively. It was concluded that ${\gamma}$-irradiated soybean proteins at doses higher than 15 kGy could be effectively protected from ruminal degradation.