• Journal of Environmental Science International
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• v.26 no.5
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• pp.651-659
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• 2017

This study aimed to estimate the effects of replacing Mushroom By-Product (MBP) with Tofu By-Product (TBP) on the chemical composition, microbes, and rumen fermentation indices of Fermented Diets (FDs). The basal diet was formulated using MBP, TBP, rice bran, molasses, and inoculants. The MBP in the basal diet was replaced with TBP at 0, 5, and 10% on Dry Matter (DM) basis for the experimental diets. The experimental diets were fermented at $39^{\circ}C$ for 144 h. Chemical composition, pH, microbes, and rumen fermentation indices of the FDs were analyzed. With increasing TBP replacement, crude protein content of FDs increased (L, P < 0.001), whereas crude ash content decreased (L, P = 0.002). Lactic acid bacteria and Bacillus subtilis contents in the TBP-replaced FDs were higher than those in the control (P < 0.05), whereas pH level and mold count were lower (P < 0.05). With increasing TBP replacement, in vitro rumen digestibility of DM (L, P = 0.053) and neutral detergent fiber (L, P = 0.024) increased, wheres rumen pH changed (P = 0.026) quadratically. Rumen total volatile fatty acid (L, P = 0.001) and iso-butyrate contents (Q, P = 0.003) increased with increasing TBP replacement. In conclusion, this study indicates that the replacement of MBP with TBP could improve the quality of FD.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8_spc
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• pp.1321-1330
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• 2019

Recent development of novel techniques in systems biology have been used to improve and manipulate the rumen microbial ecosystem and gain a deeper understanding of its physiological and microbiological interactions and relationships. This provided a deeper insight and understanding of the relationship and interactions between the rumen microbiome and the host animal. New high-throughput techniques have revealed that the dominance of Proteobacteria in the neonatal gut might be derived from the maternal placenta through fetal swallowing of amniotic fluid in utero, which gradually decreases in the reticulum, omasum, and abomasum with increasing age after birth. Multi "omics" technologies have also enhanced rumen fermentation and production efficiency of dairy goats using dietary interventions through greater knowledge of the links between nutrition, metabolism, and the rumen microbiome and their effect in the environment. For example, supplementation of dietary lipid, such as linseed, affects rumen fermentation by favoring the accumulation of ${\alpha}$-linolenic acid biohydrogenation with a high correlation to the relative abundance of Fibrobacteriaceae. This provides greater resolution of the interlinkages among nutritional strategies, rumen microbes, and metabolism of the host animal that can set the foundation for new advancements in ruminant nutrition using multi 'omics' technologies.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.3
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• pp.410-416
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• 2010

Methane emitted from ruminant livestock is regarded as a loss of feed energy and also a contributor to global warming. Methane is synthesized in the rumen as one of the hydrogen sink products that are unavoidable for efficient succession of anaerobic microbial fermentation. Various attempts have been made to reduce methane emission, mainly through rumen microbial manipulation, by the use of agents including chemicals, antibiotics and natural products such as oils, fatty acids and plant extracts. A newer approach is the development of vaccines against methanogenic bacteria. While ionophore antibiotics have been widely used due to their efficacy and affordable prices, the use of alternative natural materials is becoming more attractive due to health concerns regarding antibiotics. An important feature of a natural material that constitutes a possible alternative methane inhibitor is that the material does not reduce feed intake or digestibility but does enhance propionate that is the major hydrogen sink alternative to methane. Some implications of these approaches, as well as an introduction to antibiotic-alternative natural materials and novel approaches, are provided.

• 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.16 no.10
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• pp.1482-1486
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• 2003

In order to compare effects of feeding systems on rumen fermentation characteristics and nutrient digestion, steers were fed either total mixed ration (TMR) or separate concentrate-roughage ration (CR). Total tract digestibility of nutrients was higher in steers receiving TMR. Especially, DM, ADF and NDF in TMR were digested to a greater extent than those in CR. Rumen pH was not influenced by the feeding systems. Holstein steers on TMR had higher ruminal $NH_3$-N than those on CR. Feeding system did not alter VFA production but TMR feeding resulted in lower A/P ratio. TMR feeding tended to increase the number of bacteria and protozoa in the rumen fluid. Also steers fed TMR generally had higher fiber degrading enzyme activities, which might be the result of increased number of cellulolytic microbes in the rumen of animals on TMR. Our results indicate that TMR may provide more favorable condition for nutrient digestion both in the rumen and in the total tract of steers.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.70-74
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• 2007

An in vitro study was carried out to investigate the differences in rumen microbes and fiber degradation capacity between sheep and goats. Three local male sheep and three Inner Mongolia male cashmere goats (aged 1.5 to 2 years; weight 25.0 to 32.0 kg) were each fitted with a permanent rumen cannula used to provide rumen fluid. Cycloheximide was used to eliminate rumen anaerobic fungi. The results showed that the quantities of fungal zoospores in the culture fluid of the control group were significantly greater in the sheep than in the goats; however, bacteria and protozoa counts were significantly higher in goats than in sheep. The digestibility of straw dry matter did not differ significantly between the two species before elimination of fungi, but tended to be higher for sheep (55.4%) than for goats (53.3%). The results also indicated that bacteria counts increased significantly after elimination of anaerobic fungi; however, the digestibility of straw dry matter significantly decreased by 12.1% and 8.6% for sheep and goats respectively. This indicated that the anaerobic fungi of the rumen played an important role in degradation of fiber.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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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.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.80-86
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• 2016

An in vitro trial was conducted to examine the effects of total mixed rations (TMR) on fermentation characteristics and effective degradability (ED) by rumen microbes. Three TMR diets were growing period TMR (GR-TMR, 67% TDN), early fattening period TMR (EF-TMR, 75.4% TDN) and late fattening TMR (LF-TMR, 80% TDN). Three TMR diets (3 g of TMRs in each incubation bottles) was added to the mixed culture solution of stained rumen fluid with artificial saliva (1:1, v/v) and incubated anaerobically for 48 hours at $39^{\circ}C$. The pH in all incubation solutions tended to decrease up to 48h, but the opposite results were found in concentration of total gas production, ammonia-N and total VFA in all incubations.The total gas production (p<0.05) in LF-TMR was highest compared with those of other diets. Also, concentration of total VFA was tended to increase in LF-TMR compared with other TMR diets in all incubations. The EDDM in both EF-TMR and LF-TMR was tended to high compared with GR-TMR (p=0.100). In this in vitro trials, concentration of propionate in all incubation solution was not affected by increased concentration of TDN. The results of the present in vitro study indicate that TMR may provide more favorable condition for nutrient digestion both in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.877-884
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• 2004

Although gut microbial functions have been analyzed through cultivation of isolated microbes, molecular analysis without cultivation is becoming a popular approach in recent years. Gene cloning studies have partially revealed the mechanisms involved in fiber digestion of individual microbe. The molecular approach finally made it possible to analyze full genomes of the representative rumen cellulolytic bacteria Fibrobacter and Ruminococcus. The coming database may contain useful information such as regulation of gene expression relating to fiber digestion. Meanwhile, unculturable bacteria are still poorly characterized, even though they are main constituents of gut microbial ecosystem. The molecular analysis is essential to initiating the studies on these unculturable bacteria. The studies dealing with rumen and large intestine are revealing considerable complexity of the microbial ecosystems with many undescribed bacteria. These bacteria are being highlighted as possibly functional members contributing to feed digestion. Manipulation of gut bacteria and gut ecology for improving animal production is still at challenging stage. Bacteria newly introduced in the rumen, whether they are genetically modified or not, suffer from poor survival. In one of these attempts, Butyrivibrio fibrisolvens expressing a foreign dehalogenase was successfully established in sheep rumen to prevent fluoroacetate poisoning. This expands choice of forages in tropics, since many tropic plants are known to contain the toxic fluoroacetate. This example may promise the possible application of molecular breeding of gut bacteria to the host animals with significance in their health and nutrition. When inoculation strategies for such foreign bacteria are considered, it is obvious that we should have more detailed information of the gut microbial ecology.

• Animal Bioscience
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• v.37 no.2_spc
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• pp.337-345
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• 2024

Ruminants possess a specialized four-compartment forestomach, consisting of the reticulum, rumen, omasum, and abomasum. The rumen, the primary fermentative chamber, harbours a dynamic ecosystem comprising bacteria, protozoa, fungi, archaea, and bacteriophages. These microorganisms engage in diverse ecological interactions within the rumen microbiome, primarily benefiting the host animal by deriving energy from plant material breakdown. These interactions encompass symbiosis, such as mutualism and commensalism, as well as parasitism, predation, and competition. These ecological interactions are dependent on many factors, including the production of diverse molecules, such as those involved in quorum sensing (QS). QS is a density-dependent signalling mechanism involving the release of autoinducer (AIs) compounds, when cell density increases AIs bind to receptors causing the altered expression of certain genes. These AIs are classified as mainly being N-acyl-homoserine lactones (AHL; commonly used by Gram-negative bacteria) or autoinducer-2 based systems (AI-2; used by Gram-positive and Gram-negative bacteria); although other less common AI systems exist. Most of our understanding of QS at a gene-level comes from pure culture in vitro studies using bacterial pathogens, with much being unknown on a commensal bacterial and ecosystem level, especially in the context of the rumen microbiome. A small number of studies have explored QS in the rumen using 'omic' technologies, revealing a prevalence of AI-2 QS systems among rumen bacteria. Nevertheless, the implications of these signalling systems on gene regulation, rumen ecology, and ruminant characteristics are largely uncharted territory. Metatranscriptome data tracking the colonization of perennial ryegrass by rumen microbes suggest that these chemicals may influence transitions in bacterial diversity during colonization. The likelihood of undiscovered chemicals within the rumen microbial arsenal is high, with the identified chemicals representing only the tip of the iceberg. A comprehensive grasp of rumen microbial chemical signalling is crucial for addressing the challenges of food security and climate targets.