• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.201-205
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• 2009

Effects of Cordyceps militaris mycelia on rumen microbial fermentation were determined by measuring in vitro gas production, cellulose digestion and VFA concentrations. C. militaris mycelia was added to buffered rumen fluid with final concentrations of 0.00, 0.10, 0.15, 0.20, 0.25 and 0.30 g/L and incubation times were for 3, 6, 9, 12, 24, 36, 48 and 72 h. At all incubation times, the gas production showed a quadratic increase with the supplementation of C. militaris mycelia; maximum responses were seen with 0.25 g/L supplementation. However, the gas production was significantly lower for the 0.30 g/L supplementation than for the 0.25 g/L supplementation from 9 h to 72 h incubation. The cellulose filter paper (FP) digestion showed a quadratic increase, as did the gas production except at 3 h incubation. The concentration of total VFA was significantly increased by the supplementation of C. militaris mycelia compared with the control treatment; the highest response was also seen with 0.25 g/L supplementation. This was true for responses in the concentration of acetic and propionic acids. As opposed to other responses, the responses of pH to the supplementation of C. militaris mycelia showed a quadratic decrease from 3 h to 36 h incubation. In conclusion, C. militaris mycelia alter the mixed rumen microbial fermentation with increases in the production of gas and VFA, and cellulose FP digestion.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1625-1633
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• 2003

This study was conducted to observe effects of dietary acidogenicity value (AV) on rumen fermentation characteristics and nutrients digestibility. The AV of feedstuffs was based on the dissolution of Ca from $CaCO_3$ powder added at the end of a 24 h in vitro fermentation. Three diets were formulated to be iso-energetic and iso-nitrogenous with different AV. Two experiments were involved in this study. In experiment 1, it appears that pH, $NH_3-N$ concentration and A:P ratio tended to decrease, but gas production, VFA production and DM disappearance tended to increase with increasing dietary AV. In experiment 2, the rumen pH tended to decrease in order of high AV>medium AV>low AV treatment, respectively. There were no significant effects of dietary AV on $NH_3-N$ concentration, enzyme activity and nutrient digestibility. In addition, total VFA and individual VFA concentrations tended to increase with increasing dietary AV without significance. In fact, we hypothesized that different dietary AV would affect rumen fermentation and nutrients digestibility because dietary AV was adjusted with fermentable carbohydrate sources. The present results indicate that differences in dietary AV between treatments were too small to affect rumen fermentation and its effects were minimal.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.10
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• pp.1598-1603
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• 2018

Objective: The goal of this study was to evaluate kenaf as a roughage source in vitro and its effects on meat quality of Hanwoo (Korean native) cattle. Methods: Three roughage materials, rice straw silage, ryegrass silage, and kenaf silage, were tested in a batch culture and feeding trial. Rumen fermentation parameters, including gas, pH, volatile fatty acid (VFA), and ammonia were analyzed. In the feeding trial, Hanwoo steers ($373.5{\pm}5.1kg$, n = 36, 11 month of age) were divided into three feeding groups (n = 12 each). Animals were fed with each silage and concentrate until the fattening stage. Results: Crude protein, ether extract, and non-structural carbohydrates were greater in kenaf silage. Total gas production was higher in ryegrass silage, followed by kenaf silage and rice straw silage (p<0.05). Total VFA and individual VFA (acetate, propionate, and n-butyrate) were greater in kenaf silage than rice straw silage (p<0.05). In vitro dry matter digestibility showed a similar trend to that of total gas and VFA production; it was higher in ryegrass silage and lower in rice straw (p<0.05). Throughout the feeding trial, the rice straw silage group showed significantly greater average daily gain than did the others (p<0.05). The feed conversion ratio in the group fed kenaf silage was significantly greater than that of others (p<0.05). No significant differences were observed in yield or quality traits, including carcass weight, ribeye area, backfat thickness, and scores for marbling, meat color, and fat color (p>0.05). Conclusion: The results indicated that no negative effects on growth performance and carcass characteristics occurred across treatments. Therefore, kenaf could be substituted for rice straw, which is most widely used as a roughage source in Korea.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.125-133
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• 2012

Anaerobic digestion is an alternative method to digest food wastes and to produce methane that can be used as a renewable energy source. We investigated bacterial and archaeal community structures in a three-stage methane production process using food wastes with concomitant wastewater treatment. The three-stage methane process is composed of semianaerobic hydrolysis/acidogenic, anaerobic acidogenic, and strictly anaerobic methane production steps in which food wastes are converted methane and carbon dioxide. The microbial diversity was determined by the nucleotide sequences of 16S rRNA gene library and quantitative real-time PCR. The major eubacterial population of the three-stage methane process was belonging to VFA-oxidizing bacteria. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (Methanoculleus). Family Picrophilaceae (Order Thermoplasmatales) was also observed as a minor population. The predominance of hydrogenotrophic methanogen suggests that the main degradation pathway of this process is different from the classical methane production systems that have the pathway based on acetogenesis. The domination of hydrogenotrophic methanogen (Methanoculleus) may be caused by mesophilic digestion, neutral pH, high concentration of ammonia, short HRT, and interaction with VFA-oxidizing bacteria (Tepidanaerobacter etc.).

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.13-23
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• 2014

A lab-scale Anaerobic Baffled Reactor (ABR) was applied to treat a primary sludge taken from a municipal wastewater treatment plant. In this experiment, acidogenic reaction was promoted by operating the ABR with short hydraulic retention time (HRT) to produce sufficient volatile fatty acids (VFA) instead of production of methane. The performance of ABR on the VFA production and total solids reduction was observed with different operating conditions with 2, 4, 6, and 8 days of HRT. Corresponding organic loading rates were 6.7, 3.4, 2.2, and $1.6kgCOD_{cr}/m^3{\cdot}day$. As HRT increased the removal rate of TCOD was also increased (82.5, 84.2, 96.9, and 95.9 % in average for HRT of 2, 4, 6, and 8 days, respectively) because the settlement of solids was enhanced in the baffle by the decrease of upflow velocity. At HRT of 2 days the average concentration of VFA in the effluent was measured at $1,306{\pm}552$ mgCOD/L corresponding to 107 % increment as compared to the VFA concentration in the influent. However, as HRT increased VFA concentraiotn was decreased to $143{\pm}552$ mgCOD/L at HRT of 8 days. The reduction rates of total solids were 12.2, 26.5, 24.8, and 43.0 % for HRT of 2, 4, 6, and 8 days. As HRT increased the hydrolysis of organic particulate matters in the reactor was enhanced due to the increasing of solids retention time in the baffle zone with low upflow velocity in long HRT condition. Consequently, we found that a primary sludge became a good source of VFA production by the application of ABR process with HRT less than 4 days and the 12-26 % of total solids reduction was expected at these conditions.

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.241-250
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• 2003

Accurate and rapid evaluation of the nutritional quality of Korean straws is important because of the recent increase in the use of these feedstuffs in Korean. The aim of the study was to establish with relationships between ruminal fermentation of Korean straws and in vitro gas production using a pressure transducer. The pressure transducer system includes pressure censors, AD board, LED monitor, and the computer with real-time graphics. Both gas production and DM digestibility data were fitted into the exponential equation P = a + b (1-e-$1-e^{-ct}$). The initial rate of gas production was highest for rice straw, followed by barley straw and wheat straw. The gas production rate of constant (c) in gas production for rice straw, wheat straw, and barley straw were 3.8, 2.5, and 2.5 $%h^{－1}$, respectively. Total VFA concentration (mM) produced after 72h incubation was similar among three Korean straws, even though was variable during the early (12h) fermentation. Volume of gas production was related (P> 0.05: r = 0.76 to 0.83) to DM disappearance and also strongly related (p< 0.05: r = 0.91 to 0.98) to VFA concentration at all incubation times. Linear correlation showed between gas production and DM disappearance and VFA by in vitro will be matched in in vivo digestibility.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1040-1048
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• 1999

Four ruminally fistulated crossbred $(Sahiwal{\times}Holstein\;Friesan)$ adult (~6 yr.) cattle of about $318{\pm}16kg$ body weight were randomly assigned in an experiment based on $4{\times}4$ latin square design to study the effect of different level of barseem (Trifolium alexendrinum) supplementation to wheat straw based diet on intake, digestion, VFA production, eating behaviour and passage rate. Four dietary treatments were wheat straw ad lib. (I), supplementation to wheat either 15(II), 30(III) or 45(IV)% of berseem. Mean total volatile fatty acids (TVFA) concentration in rumen liquor was 58.45, 66.14, 77.92 and 78.64 mmol/l. TVFA concentration in rumen liquor increased significantly (p<0.01) with increased level of berseem supplementation upon 30% level of breseem. Two peaks of TVFA concentration was observed at 4 and 8 h post feeding. Brseem supplementation showed no significant effect on daily time spent for eating, ruminating or idling, chews per minute or number of rumination boli ingested per minute. Time spent for eating and ruminating one kg neutral detergent fibre (NDF) was significantly (p<0.05) less in breseem supplemented groups. Animals in groups I, II, III and IV consumed 26, 34, 47 and 57% of DM within 1st 4 h and 64, 70, 70 and 77% of total DM within 1st 8 h of offering. All the animals consumed more than 90% of their DMI within 12 h. Active period of rumination was observed 8h post feeding reached the peak at 16 h post feeding, then declined and animals spend considerable time idling in last 4 h of 24 h feeding cycle. Berseem supplementation showed no significant effect on eating and rumination time. It is concluded that berseem supplementation upon 30% increases the efficiency of chewing during eating and rumination, which results in increase intake and TVFA production and nutrient digestibility.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.155-162
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• 2013

The objective of this study is to investigate the effects of Cynanchum wilfordii (CW) on cell viability, anti-oxidant activity, volatile fatty acid (VFA) production and methane gas production. Collected rumen fluid incubated with CW powder (1% w/v) for 12 and 24 hours were analyzed for pH, VFAs and methane. Alamar blue assay showed no significant difference on the viability of 3T3-L1 and C2C12 cells treated with CW for 24 hours. TBARS data showed a dose dependent increase on the antioxidant activity of CW. VFAs increased in the CW-treated groups compared to the control group. In addition, propionate increased more than other VFAs by the treatment with CW. There was a significant decrease in methane gas production in batch culture treated with CW in 12hrs. In conclusion, it was suggested that Cynanchum wilfordii could manipulate rumen fermentation considered by increasing VFA production and inhibition of methanogenesis.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.43-53
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• 1997

In this research, the synthetic livestock wastewater was prepared to study the characteristics of organic matter removal, the change of VFA production, and the amount of gas production with respect to the change of ammonium nitrogen concentration in the waste using anaerobic fixed bed process, which is an anaerobic biofilm process. The HRT and operation temperature were 1 day and $35{\pm}1^{\circ}C$, respectively. Also, the characteristics of organic matter removal and the inhibitory effect on microorganism in the anaerobic process were studied on the organic loading and ammonium nitrogen concentration. The results obtained were as follows: For COD loading of $10kg/m^3$-day and five levels of ammonium nitrogen concentration ranging from 1,000 to 5,000 mg/L, organic removal efficiencies were about 81, 74, 67, 58, and 51%, and gas productions were 3,860, 3,520, 3,240, 3,020, and 2,790 ml/l-day, respectively. Average methane contents in the gas produced on COD loading of $10kg/m^3$-day was about 76%. Throughout the whole period of experiment, remaining VFA (as COD base) in the effluent was over 90% of remaining COD. This result indicated the inhibitory effect of high concentration of ammonium nitrogen through the facts that accumulated VFA was almost COD and organic removal efficiency decreased also with the increase of ammonium nitrogen. Especially, that implys which high concentration of ammonium nitrogen not only inhibits methane forming bacteria, but also acid forming bacteria.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.708-714
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• 1999

Fermentation of legume fodder tree leaves by rumen microorganisms was evaluated. The substrates were sun-dried, ground leaves. Gas and volatile fatty acid (VFAs) production were estimated. Using gas production as an index of fermentation at 12 h, the leaves tested ranked as follows; Chamaecytisus palmensis>Gliricidia sepium>Sebania sesban>Tephrosia bracteolate>Leucaena pallida>Vernonia amygdalina>Acacia sieberiana>Sesbania goetzei>Acacia angustissima. Using VFA production, the ranking was a follows; G. sepium>S. sesban>S. goetzei>L. pallida>C. palmensis/V. amygdalina>T. bracteolate> A. sieberiana>A. angustissima. Absolute gas or VFA production rates, were also used to rank the leaves. Extracts (70% acetone) of A. angustissima inhibited the growth of Ruminococcus albus 8, R. flavefaciens FD-1, Prevotella ruminicola D3ID and Streptococcus bovis JBI while the trowth of Selenomonas ruminantium D was depressed when 0.6 ml exracts were added. C. palmensis water extracts enhanced cellulose hydrolysis by R. flavefaciens FD-1. All extracts reduced celluloysis by R. albus 8. R. flavefaciens FD-1 hydrolyzed more (p<0.001) cellulose than R. albus 8.