• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1216-1220
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• 2001

Effect of hydroquinone (HQ) on rumen urease activity was studied. Hydroquinone at concentrations of 0.01 ppm, 0.1 ppm, 1 ppm, and 10 ppm inhibited urease activity of intact rumen microbes in vitro by 25%, 34%, 55% and 64% respectively. In the presence of low concentrations of $\beta$-mercaptoethanol, rumen urease could be solubilized and partially purified. The Km for the enzyme was $2{\times}10^{-3}$ M with Vmax of $319.4{\mu}moles/mg$ min. The kinetics of inhibition with partially purified rumen urease was investigated. The result showed that the inhibitory effect was not eliminated by increasing urea concentrations indicating a noncompetitive effect in nature with an inhibition constant $1.2{\times}10^{-5}$ M. Hydroquinone at the concentration of 10 ppm produced 64% urease inhibition, did not affect ruminal total dehydrogenase and proteolytic enzyme (p>0.05), but increased cellulase activity by 28% (p<0.05) in vitro. These results indicated that hydroquinone was a effective inhibitor of rumen urease and could effectively delay urea hydrolysis without a negative effect. The inhibitor appeared to offer a potential to improve nitrogen utilization by ruminants fed diets containing urea.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1728-1735
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• 2008

The present study was conducted with four ruminally canulated Holstein cows to observe the effects of monensin or fish oil on diet fermentation and production of conjugated linoleic acids (CLAs) in the rumen when fed diets supplemented with soybean oil and sodium bicarbonate. Cows of the control treatment were fed a basal diet (CON) consisting of 60% commercial concentrate and 40% chopped rye grass hay. Cows of other treatments were fed the same diet as CON, but the concentrate was supplemented with 7% of soybean oil and 0.5% of sodium bicarbonate (SO-B), SO-B supplemented with monensin (30 ppm, SO-BM) or concentrate supplemented with 6.3% of soybean oil, 0.5% of sodium-bicarbonate, 30 ppm of monensin and 0.7% of fish oil (SO-BMF). Dry matter (DM) intake of the cows was significantly (p<0.011) reduced by feeding the SO-BMF diet compared to the other diets which did not differ in DM intake. Whole tract digestibility of major dietary components was significantly (p<0.004-0.027) higher for SO-BMF than the other supplement-containing diets. Dietary supplements did not clearly affect rumen pH and ammonia concentrations compared to the CON diet. Significantly reduced (p<0.05) total VFA concentration was obtained by the addition of fish oil to the diet (SO-BMF) compared to other diets. No differences, however, were obtained in major VFA proportions as well as in total VFA between the supplemented diets. The SO-BM diet increased (p<0.01-0.05) the concentrations of trans-11 $C_{18:1}$ and linoleic acid in rumen fluid. Total CLA concentration was also increased by the feeding of SO-B and SO-BM diets during early fermentation times (up to 3 h) post-feeding. Cis-9, trans-11 CLA concentration in rumen fluid was highest (p<0.05) for SO-B up to 1 h while the highest (p<0.01) value for SO-BM occurred at 3 h post-feeding. An increased trans-10, cis-12 CLA concentration was obtained from the SO-B and SO-BM diets at 1 and 3 h post feeding compared to the other diets. Supplementation of oils with monensin and sodium bicarbonate increased (p<0.05) the proportions of $C_{18:1}$ and CLA in the plasma of cows, but the effect of monensin and/or fish oil was limited to trans-10, cis-12 CLA.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.990-996
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• 2005

The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y$\alpha$) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y$\alpha$ and lag time in total gas has showed significant (p<0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p<0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y$\alpha$ indicated that the effect of diet on Y$\alpha$ was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y$\alpha$, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.285-294
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• 2011

The abatement of methane emission from ruminants is an important global issue due to its contribution to greenhouse gas with carbon dioxide. Methane is generated in the rumen by methanogens (archaea) that utilize metabolic hydrogen ($H_2$) to reduce carbon dioxide, and is a significant electron sink in the rumen ecosystem. Therefore, the competition for hydrogen used for methanogenesis with alternative reductions of rumen microbes should be an effective option to reduce rumen methanogenesis. Some methanogens parasitically survive on the surface of ciliate protozoa, so that defaunation or decrease in protozoa number might contribute to abate methanogenesis. The most important issue for mitigation of rumen methanogenesis with manipulators is to secure safety for animals and their products and the environment. In this respect, prophylactic effects of probiotics, prebiotics and miscellaneous compounds to mitigate rumen methanogenesis have been developed instead of antibiotics, ionophores such as monensin, and lasalocid in Japan. Nitrate suppresses rumen methanogenesis by its reducing reaction in the rumen. However, excess intake of nitrate causes intoxication due to nitrite accumulation, which induces methemoglobinemia. The nitrite accumulation is attributed to a relatively higher rate of nitrate reduction to nitrite than nitrite to ammonia via nitroxyl and hydroxylamine. The in vitro and in vivo trials have been conducted to clarify the prophylactic effects of L-cysteine, some strains of lactic acid bacteria and yeast and/or ${\beta}$1-4 galactooligosaccharide on nitrate-nitrite intoxication and methanogenesis. The administration of nitrate with ${\beta}$1-4 galacto-oligosaccharide, Candida kefyr, and Lactococcus lactis subsp. lactis were suggested to possibly control rumen methanogenesis and prevent nitrite formation in the rumen. For prebiotics, nisin which is a bacteriocin produced by Lactococcus lactis subsp. lactis has been demonstrated to abate rumen methanogenesis in the same manner as monensin. A protein resistant anti-microbe (PRA) has been isolated from Lactobacillus plantarum as a manipulator to mitigate rumen methanogenesis. Recently, hydrogen peroxide was identified as a part of the manipulating effect of PRA on rumen methanogenesis. The suppressing effects of secondary metabolites from plants such as saponin and tannin on rumen methanogenesis have been examined. Especially, yucca schidigera extract, sarsaponin (steroidal glycosides), can suppress rumen methanogenesis thereby improving protein utilization efficiency. The cashew nutshell liquid (CNSL), or cashew shell oil, which is a natural resin found in the honeycomb structure of the cashew nutshell has been found to mitigate rumen methanogenesis. In an attempt to seek manipulators in the section on methane belching from ruminants, the arrangement of an inventory of mitigation technologies available for the Clean Development Mechanism (CDM) and Joint Implementation (JI) in the Kyoto mechanism has been advancing to target ruminant livestock in Asian and Pacific regions.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.8
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• pp.1088-1097
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• 2014

The study aimed to investigate the effects of gynosaponin on in vitro methanogenesis under different forage-concentrate ratios (F:C ratios). Experiment was conducted with two kinds of F:C ratios (F:C = 7:3 and F:C = 3:7) and gynosaponin addition (0 mg and 16 mg) in a $2{\times}2$ double factorial design. In the presence of gynosaponin, methane production and acetate concentration were significantly decreased, whereas concentration of propionate tended to be increased resulting in a significant reduction (p<0.05) of acetate:propionate ratio (A:P ratio), in high-forage substrate. Gynosaponin treatment increased (p<0.05) the butyrate concentration in both F:C ratios. Denaturing gradient gel electrophoresis (DGGE) analysis showed there was no apparent shift in the composition of total bacteria, protozoa and methanogens after treated by gynosaponin under both F:C ratios. The real-time polymerase chain reaction (PCR) analysis indicated that variable F:C ratios significantly affected the abundances of Fibrobacter succinogenes, Rumninococcus flavefaciens, total fungi and counts of protozoa (p<0.05), but did not affect the mcrA gene copies of methanogens and abundance of total bacteria. Counts of protozoa and abundance of F.succinogenes were decreased significantly (p<0.05), whereas mcrA gene copies of methanogens were decreased slightly (p<0.10) in high-forage substrate after treated by gynosaponin. However, gynosaponin treatment under high-concentrate level did not affect the methanogenesis, fermentation characteristics and tested microbes. Accordingly, overall results suggested that gynosaponin supplementation reduced the in vitro methanogenesis and improved rumen fermentation under highforage condition by changing the abundances of related rumen microbes.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1381-1388
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• 2012

An in vitro experiment was conducted to examine the effects of defaunation (removal of protozoa) on ruminal fermentation characteristics, $CH_4$ production and degradation by rumen microbes when incubated with cereal grains (corn, wheat and rye). Sodium lauryl sulfate as a defaunation reagent was added into the culture solution at a concentration of 0.000375 g/ml, and incubated anaerobically for up to 12 h at $39^{\circ}C$. Following defaunation, live protozoa in the culture solution were rarely observed by microscopic examination. A difference in pH was found among grains regardless of defaunation at all incubation times (p<0.01 to 0.001). Defaunation significantly decreased pH at 12 h (p<0.05) when rumen fluid was incubated with grains. Ammonia-N concentration was increased by defaunation for all grains at 6 h (p<0.05) and 12 h (p<0.05) incubation times. Total VFA concentration was increased by defaunation at 6 h (p<0.05) and 12 h (p<0.01) for all grains. Meanwhile, defaunation decreased acetate and butyrate proportions at 6 h (p<0.05, p<0.01) and 12 h (p<0.01, p<0.001), but increased the propionate proportion at 3 h, 6 h and 12 h incubation (p<0.01 to 0.001) for all grains. Defaunation increased in vitro effective degradability of DM (p<0.05). Production of total gas and $CO_2$ was decreased by defaunation for all grains at 1 h (p<0.05, p<0.05) and then increased at 6 h (p<0.05, p<0.05) and 12 h (p<0.05, p<0.05). $CH_4$ production was higher from faunation than from defaunation at all incubation times (p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1659-1676
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• 2002

Ruminant animals develop a diverse and sophisticated microbial ecosystem for digesting fibrous feedstuffs. Plant cell walls are complex and their structures are not fully understood, but it is generally believed that the chemical properties of some plant cell wall compounds and the cross-linked three-dimensional matrix of polysaccharides, lignin and phenolic compounds limit digestion of cell wall polysaccharides by ruminal microbes. Three adaptive strategies have been identified in the ruminal ecosystem for degrading plant cell walls: production of the full slate of enzymes required to cleave the numerous bonds within cell walls; attachment and colonization of feed particles; and synergetic interactions among ruminal species. Nonetheless, digestion of fibrous feeds remains incomplete, and numerous research attempts have been made to increase this extent of digestion. Exogenous fibrolytic enzymes (EFE) have been used successfully in monogastric animal production for some time. The possibility of adapting EFE as feed additives for ruminants is under intensive study. To date, animal responses to EFE supplements have varied greatly due to differences in enzyme source, application method, and types of diets and livestock. Currently available information suggests delivery of EFE by applying them to feed offers the best chance to increase ruminal digestion. The general tendency of EFE to increase rate, but not extent, of fibre digestion indicates that the products currently on the market for ruminants may not be introducing novel enzyme activities into the rumen. Recent research suggests that cleavage of esterified linkages (e.g., acetylesterase, ferulic acid esterase) within the plant cell wall matrix may be the key to increasing the extent of cell wall digestion in the rumen. Thus, a crucial ingredient in an effective enzyme additive for ruminants may be an as yet undetermined esterase that may not be included, quantified or listed in the majority of available enzyme preparations. Identifying these pivotal enzyme(s) and using biotechnology to enhance their production is necessary for long term improvements in feed digestion using EFE. Pretreating fibrous feeds with alkali in addition to EFE also shows promise for improving the efficacy of enzyme supplements.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.567-586
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• 2001

Gastrointestinal tract of ruminants as well as monogastric animals are colonised by a variety of microorganisms including bacteria, fungi and protozoa. Gastrointestinal ecosystem, especially the rumen is emerging as an important source for enrichment and natural selection of microbes adapted to specific conditions. It represents a virtually untapped source of novel products (e.g. enzymes, antibiotics, bacteriocins, detoxificants and aromatic compounds) for industrial and therapeutic applications. Several gastrointestinal bacteria and fungi implicated in detoxification of anti-nutritional factors (ANFs) can be modified and manipulated into promising system for detoxifying feed stuffs and enhancing fibre fermentation both naturally by adaptation or through genetic engineering techniques. Intestinal lactobacilli, bifidobacteria and butyrivibrios are being thoroughly investigated and widely recommended as probiotics. Restriction endonucleases and native plasmids, as stable vectors and efficient DNA delivery systems of ruminal and intestinal bacteria, are increasingly recognised as promising tools for genetic manipulation and development of industrially useful recombinant microbes. Enzymes can improve the nutrient availability from feed stuffs, lower feed costs and reduce release of wastes into the environment. Characterization of genes encoding a variety of commercially important enzymes such as cellulases, xylanases, $\beta$-glucanases, pectinases, amylases and phytases will foster the development of more efficacious and viable enzyme supplements and enzyme expression systems for enhancing livestock production.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.351-362
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• 1998

Microbial growth efficiency in the rumen was studied in sheep given hourly, 31.25 g oaten chaff with either 0.31 and 0.88 g urea or 1.88 and 5.63 g casein (exp. 1) and 33.33 g oaten chaff with 1.04 casein or 0.3, 0.6 and 0.9 g urea or the mixture of the casein and urea (exp. 2). Concentrations of ruminal fluid ammonia increased with increasing nitrogenous supplements. Organic matter digestibility in sacco in the rumen was not different irrespective of N sources. Isoacids and valeric acid increased with increasing ingested casein but decreased with increasing urea intake. Peptide and amino acid pools in ruminal fluid increased with increasing ammonia concentrations (exp. 2) suggesting that proteolytic activity and transportation of peptides and amino acids across microbial membrane of rumen microbes may be regulated by the metabolite mechanism (intracellular amino acids and $NH_4{^+}$, respectively). Densities of total viable and cellulolytic bacteria in ruminal fluid increased with increasing ammonia levels but that of small Entodinia decreased. The density of fungal sporangia growth on oat leaf blades decreased with increasing ammonia concentrations but appeared to remain constant in the presence of casein. Efficiency of net microbial cell synthesis was 15-28% higher when ammonia concentrations increased from 100 to above 200 mg N/l regardless of N sources. In conclusion, supplementation of preformed protein had no effect on rumen digestion and microbial growth efficiency. This could not be accounted for its effect on ruminal fluid ammonia. Increased microbial growth efficiency with increasing ammonia levels may be due to a reduction in the turnover of microbial cells within the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.531-537
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• 2017

Objective: This experiment was conducted to explore the impact of diet on the ruminal microbial community in goats. Methods: Twelve goats were divided into two groups and fed complete feed (CF) or all forage (AF) diet. The total microbial DNAs in the rumen liquid were extracted. The V4 region of microbial 16S rRNA genes was amplified and sequenced using high-throughput. Information of sequences was mainly analyzed by QIIME 1.8.0. Results: The results showed that Bacteroidetes and Firmicutes were the most predominant microbial phyla in the rumen of all goats. At genus level, the abundance of fiber-digesting bacteria such as Ruminococcus and Lachnospiracea incertae sedis was significantly higher in AF than that in CF, while the levels of fat-degrading bacterium Anaerovibrio and protein-degrading bacterium Pseudomonas were opposite. The core shared genera, Prevotella and Butyrivibrio were widespread in the rumen of goats and no significant difference was observed in relative abundance between groups. Conclusion: We concluded that the richness of fiber-, protein-, and fat-digesting bacteria was affected by diet and tended to increase with the rise of their corresponding substrate contents in the ration; some bacteria shared by all goats maintained stable despite the difference in the ration, and they might be essential in maintaining the normal function of rumen.