• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.68-72
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• 2004

The effects of the addition of yeast on in vitro roughage degradability and methane production were investigated in order to clarify the effects of yeast on the rumen microbes and to establish methods of rumen manipulation. Three roughages (whole crop corn, rice straw and Italian ryegrass) were incubated for 3, 6, 12 and 24 h with or without dried beer yeast following the method described by Tilley and Terry. Using the same method, these roughages were incubated with or without yeast extract, albumin or purified DNA. In vitro methane production was measured with or without dried beer yeast at 12 and 24 h. The degradability of yeast was found to be 57 and 80% at 12 and 24 h, respectively. The rate of degradation of fraction b was 6.16%/h. There was a significant increase in roughage degradability at 6 h (p<0.05), 12 h (p<0.05) and 24 h (p<0.01) by dried yeast addition. The degradability of all three roughages was higher in the samples treated with yeast extract than in the no addition samples except in the case of rice straw incubated for 12 h. Nevertheless, the magnitude of increment was smaller with the addition of yeast extract than without the addition of yeast. With the addition of purified DNA, there were significant increases in roughage degradability at 6 h (p<0.01), 12 h (p<0.01) and 24 h (p<0.05); however, higher degradability values were detected in the samples to which albumin was added, particularly at 6 h. If the degradability values of the no addition samples with those of samples containing yeast, yeast extract, DNA and albumin were compared, the largest difference was found in the samples to which yeast was added, although it is worth noting that higher values were observed in the yeast extract samples than in the DNA or albumin samples, with the exception of the case of rice straw incubated for 24 h. Methane production was significantly increased at both 12 and 24 h incubation. The increment of roughage degradation and methane production brought about by the addition of dried beer yeast to the samples was thought to be due to the activation of rumen microbes. Water soluble fraction of yeast also seemed to play a role in ruminal microbe activation. The increment of degradability is thought to be partially due to the addition of crude protein or nucleic acid but it is expected that other factors play a greater role. And those factors may responsible for the different effects of individual yeast on ruminal microbes.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.10
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• pp.1424-1436
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• 2013

The objective of this study was to investigate the effect of banana flower powder (BAFLOP) supplementation on gas production kinetics and rumen fermentation efficiency in in vitro incubation with different ratios of roughage to concentrate in swamp buffalo and cattle rumen fluid. Two male, rumen fistulated dairy steers and swamp buffaloes were used as rumen fluid donors. The treatments were arranged according to a $2{\times}2{\times}3$ factorial arrangement in a Completely randomized design by using two ratios of roughage to concentrate (R:C; 75:25 and 25:75) and 3 levels of BAFLOP supplementation (0, 2 and 4% of dietary substrate) into two different kinds of rumen fluid (beef cattle and swamp buffalo). Under this investigation, the results revealed that the rumen ecology was affected by R:C ratio. The pH declined as a result of using high concentrate ratio; however, supplementation of BAFLOP could buffer the pH which led to an improvement of ruminal efficiency. BAFLOP supplementation affected acetic acid (C2) when the proportion of concentrate was increased. However, there were no effect on total volatile fatty acid (TVFA) and butyric acid (C4) by BAFLOP supplementation. The microbial community was affected by BAFLOP supplementation, especially the bacterial population. As revealed by real-time PCR, the populations of F. succinogenes and R. albus were reduced by the high concentrate treatments while that of R. flavafaciens were increased. The populations of three dominant cellulolytic bacteria were enhanced by BAFLOP supplementation, especially on high concentrate diet. BAFLOP supplementation did not influence the ammonia nitrogen ($NH_3$-N) concentration, while R:C did. In addition, the in vitro digestibility was improved by either R:C or BAFLOP supplementation. The BAFLOP supplementation showed an effect on gas production kinetics, except for the gas production rate constant for the insoluble fraction (c), while treatments with high concentrate ratio resulted in the highest values. In addition, BAFLOP tended to increase gas production. Based on this study, it could be concluded that R:C had an effect on rumen ecology both in buffalo and cattle rumen fluid and hence, BAFLOP could be used as a rumen buffering agent for enhancing rumen ecology fed on high concentrate diet. It is recommended that level of BAFLOP supplementation should be at 2 to 4% of total dry matter of substrate. However, in vivo trials should be subsequently conducted to investigate the effect of BAFLOP in high concentrate diets on rumen ecology as well as ruminant production.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1137-1142
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• 2003

In a balanced incomplete block design, two dry Holstein cows were used to investigate the effect of $\beta$ 1-4 galactooligosaccharides (GOS) supplementation on nitrogen (N) utilization, rumen fermentation and microbial N supply in the rumen. During the experiment, cows were fed four diets: orchardgrass (Dactylis glomerata L.) silage (OS), OS with GOS supplementation (OSG), OS mixed with alfalfa (Medicago sativa L.) silage (MS) and MS with GOS supplementation (MSG). GOS was supplemented at 2% of dry matter intake. Diets were fed at maintenance level of protein and energy. Results showed that N digestion was affected by silage and interaction of silage and GOS supplementation. Cows fed OSG had the highest N digested (p<0.05) followed by MS, OS and MSG. Supplementation of GOS to OS or MS diets tended to improve N utilization through reducing the N losses on dairy cows. There was no effect of GOS supplementation on rumen fermentation parameters (i.e. pH, $NH_3$-N and total VFA) at 1 h and 6 h after feeding. Compared to cows fed MS, cows fed OS silage had higher (p<0.05) allantoin excretion (80.8 vs. 67.1 mmol/d) and higher (p<0.05) total purine derivatives excretion (92.9 vs. 78.5 mmol/d). The microbial N supply in cows fed OSG was higher (p<0.05) than those fed OS, MS and MSG.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.451-456
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• 2000

Fifty mid-lactation Holstein cows were used in a six-week feeding trial to study effects of high-forage, and high-fat diets on blood constituents, rumen fermentation and dry matter digestibility. Cows were divided into 10 replicates, each consisting of five cows. Each cow was assigned to a control (diet 1) or one of the four experimental diets (high-forage (75%), high-fat (7.5%) (diet 2); high-forage. medium-fat (5.0%) (diet 3); medium forage (65%), high-fat (diet 4); medium-forage, medium-fat (diet 5)), or a control diet containing about 50% forage and 2% fat. All diets were isonitrogenous (17.7% crude protein). The forage mixture consisted of 20% alfalfa hay, 40% alfalfa haylage, and 40% corn silage. Supplemental fat included 80% rumen-protected fat and 20% yellow grease. A non-significant difference was observed in concentrations of blood glucose for cows on different experimental and control diets. Plasma nonesterified fatty acids (NEFA) were higher in cows consuming experimental diets than those consuming the control diet. However, differences in NEFA concentrations in the plasma of cows consuming diets with different forage and fat levels were not significant. Rumen pH, concentration of volatile fatty acids (VFA) in rumen contents, and dry matter digestibility of control and experimental diets, and diets with different levels of forage and supplemental fat did not differ significantly.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.165-174
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• 2012

This study was conducted to develop Miscanthus as a new roughage resource for ruminant animals. Miscanthus sacchariflorus var. No 1, a newly developed germtype in Korea, was harvested at late maturity stage and its effect on rumen pH, ammonia nitrogen, gas production, volatile fatty acid (VFA) production and digestibility were evaluated using in vitro rumen fermentation. The effects of Miscanthus were compared with rice straw. Miscanthus showed significantly higher pH compared to rice straw (p<0.01). As for ammonia nitrogen, there was no significant difference after 12 h of incubation (p>0.05). Gas production in Miscanthus was significantly lower than that of rice straw in overall incubation time (p<0.05) after 6 h of incubation. In VFA production, acetate, propionate, butyrate, valerate and total VFA production in Miscanthus were lower than those in rice straw. However, production of iso-butyrate and iso-valerate were not different in between two forage materials. Dry matter digestibility of Miscanthus was significantly lower than rice straw (p<0.05) during 12~24 h of incubation. As a result, the availability of Miscanthus as roughage source showed approximately 80% that of rice straw.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.48-53
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• 2001

An in vitro study was conducted to examine the effect of sources and the addition levels of carbohydrates on fermentation characteristics, bacterial growth, and hydrogenation of linoleic acid ($C_{18:2}$) by mixed ruminal bacteria. Starch and cellobiose were added to the 200 ml non-selective basal media at the levels of 0.20 and 0.35% (w/v), respectively. Linoleic acid (66.8~79.6 mg) in the absorbed form into the pieces of nylon cloth was also added to the media of 5 treatments including control which was not added with carbohydrate. Three mls of rumen fluid strained through 12 layers of cheese cloth were added to each medium, and were incubated anaerobically in the shaking incubator of $39^{\circ}C$ for 24 hours. During 24 h incubation the pH in incubation media of all treatments was maintained above 6.6 by the addition of sodium bicarbonate. The pH and ammonia concentration of incubation media were not clearly influenced by the sources and addition levels of carbohydrates while additions of carbohydrates increased (p<0.0001) VFA concentration at the 24 h incubation. Molar proportions of acetate were reduced (p<0.0004) while those of propionate were increased (p<0.0006) by the addition of carbohydrates. But the differences in concentration and molar proportions of the VFA were small between the sources or the addition levels. Bacterial growth was faster (p<0.0004) in the starch added treatments than in the cellobiose added ones and control, but no differences were found between addition levels. Increased (p<0.0487) hydrogenation was observed from the starch added treatments compared to the cellobiose added ones, but there was no difference between addition levels.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.952-959
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• 2016

The objective of this study was to investigate the effects of 11 active compounds of essential oils (ACEO) on rumen fermentation characteristics and methane production. Two trials were conducted. In trial 1, ACEO (eugenol, carvacrol, citral, limonene, 1,4-cineole, p-cymene, linalool, bornyl acetate, ${\alpha}$-pinene, and ${\beta}$-pinene) at a dose of $1,000{\mu}L/L$ were incubated for 24 h in diluted rumen fluid with a 70:30 forage:concentrate substrate (16.2% crude protein; 36.6% neutral detergent fiber). Three fistulated Holstein cows were used as donors of rumen fluid. The reduction in methane production was observed with nine ACEO (up to 86% reduction) compared with the control (p<0.05). Among these, only limonene, 1,4-cineole, bornyl acetate, and ${\alpha}$-pinene did not inhibit volatile fatty acid (VFA) production, and only bornyl acetate produced less methane per mol of VFA compared with the control (p<0.05). In a subsequent trial, the effects on rumen fermentation and methane production of two concentrations (500 and $2,000{\mu}L/L$) of bornyl acetate, the most promising ACEO from the first trial, were evaluated using the same in vitro incubation method that was used in the first trial. In trial 2, monensin was used as a positive control. Both doses of bornyl acetate decreased (p<0.05) methane production and did not inhibit VFA production. Positive effects of bornyl acetate on methane and VFA production were more pronounced than the effects of monensin. These results confirm the ability of bornyl acetate to decrease methane production, which may help to improve the efficiency of energy use in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.75-81
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• 2007

The object of this study was to determine the influence of supplementation of concentrate containing high levels of cassava chip on rumen ecology, microbial protein and digestibility of nutrients. Four, rumen fistulated crossbred beef steers with initial body weight of 400${\pm}$10 kg were randomly assigned according to a 4${\times}$4 Latin square design. The dietary treatments were concentrate cassava chip based offering at 0, 1, 2 and 3% BW with urea-treated rice straw fed ad libitum. It was found that ruminal pH was significantly decreased with increase of concentrate. Volatile fatty acids (VFA) concentration in the rumen was significantly different among treatments. In addition, a molar proportion of propionate was higher in supplemented groups at 2 and 3% BW (p<0.05), leading to significantly decreased acetate:propionate ratio. Furthermore, microbial N supply was significantly improved and was highest at 2% BW supplementation. The efficiency of rumen microbial-N synthesis based on organic matter (OM) truly digested in the rumen was highest in level of concentrate supplementation at 2% BW (80% of cassava chip in diets). Moreover, bacterial populations such as amylolytic bacteria was linearly increased, while cellulolytic bacteria was linearly decreased (p<0.01) when cattle received concentrate supplementation in all levels. The total protozoal counts were significantly increased, while fungal zoospores were dramatically decreased in cattle receiving increased levels of concentrate. In conclusion, cassava chip can be use as energy source at 80% in concentrate and supplementation of concentrate at 2% BW with urea-treated rice straw as roughage could improve rumen fermentation efficiency in beef cattle.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.281-296
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• 2018

This study was conducted to evaluate the effect of different processing of rice on rumen fermentation in in vitro and in situ experiments. Different processing treatments (extruding, roasting, and steaming) were used in this study and all treatments were ground through a cyclone mill (Foss, Hillerød, Denmark) fitted with a 1 mm screen. Non-treated rice was considered to a control substrate. Then, all treatments were used in in vitro and in situ experiments. Total gas production and dry matter digestibility in control were lower than any other treatment at all incubation times (P<0.01). The lowest ammonia nitrogen ($NH_3-N$) concentration was observed in control among treatments at 6, 12, and 24 h incubation (P<0.01). Extruding had a highest total volatile fatty acids (VFA) concentration at 6, 12 h incubation (P<0.01) and Steaming exhibited a highest total VFA at 24 h (P<0.01). The lowest total VFA concentration was observed in control at 6, 12, and 24 h (P<0.01). In an in situ, The highest value of soluble fraction, degradation rates, effective degradability was observed in extruding (P<0.01). It was considered that feed processing increased dry matter digestibility, total VFA concentration, and decreased pH as well as $NH_3-N$ concentration indicating that processing may increase nutrient degradation of rice in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.113-128
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• 1999

Protozoa can represent as half of the total rumen microbial biomass. Around 10 genera are generally present on the same time in the rumen. Based on nutritional aspects they can be divided in large entodiniomorphs, small entodiniomorphs and isotrichs. Their feeding behaviour and their enzymatic activities differ considerably. Many comparisons between defaunated and refaunated animals were carried out during the last two decades to explain the global role of protozoa at the ruminal or animal levels. It is now generally considered that a presence of an abundant protozoal population in the rumen has a negative effect on the amino acid (AA) supply to ruminants and contribute to generate more methane but, nevertheless, protozoa must not be considered as parasites. They are useful for numerous reasons. They stabilise rumen pH when animal are fed diets rich in available starch and decrease the redox potential of rumen digesta. Because cellulolytic bacteria are very sensitive to these two parameters, protozoa indirectly stimulate the bacterial cellulolytic activity and supply their own activity to the rumen microbial ecosystem. They could also supply some peptides in the rumen medium which can stimulate the growth of the rumen microbiota, but this aspect has never been considered in the past. Their high contribution to ammonia production has bad consequences on the urinary nitrogen excretion but means also that less dietary soluble nitrogen is necessary when protozoa are present. Changes in the molar percentages of VFA and gases from rumen fermentations are not so large that they could alter significantly the use of energy by animals. The answer of animals to elimination of protozoa (defaunation) depends on the balance between energy and protein needs of animals and the supply of nutrients supplied through the diet. Defaunation is useful in case of diets short in protein nitrogen but not limited in energy supply for animals having high needs of proteins.