• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.4
• /
• pp.471-478
• /
• 2011

The objectives were to compare the ability of various rumen microbial fractions to reduce nitrate and to assess the effect of nitrate on in vitro fermentation characteristics. Physical and chemical methods were used to differentiate the rumen microbial population into the following fractions: whole rumen fluid (WRF), protozoa (Pr), bacteria (Ba), and fungi (Fu). The three nitrogen substrate treatments were as follows: no supplemental nitrogen source, nitrate or urea, with the latter two being isonitrogenous additions. The results showed that during 24 h incubation, WRF, Pr and Ba fractions had an ability to reduce nitrate, and the rate of nitrate disappearance for the Pr fraction was similar to the WRF fraction, while the Ba fraction needed an adaptation period of 12 h before rapid nitrate disappearance. The WRF fraction had the greatest methane ($CH_4$) production and the Pr fraction had the greatest prevailing $H_2$ concentration (p<0.05). Compared to the urea treatment, nitrate diminished net gas and $CH_4$ production during incubation (p<0.05), and ammonia-N ($NH_3$-N) concentration (p<0.01). Nitrate also increased acetate, decreased propionate and decreased butyrate molar proportions (p<0.05). The Pr fraction had the highest acetate to propionate ratio (p<0.05). The Pr fraction as well as the Ba fraction appears to have an important role in nitrate reduction. Nitrate did not consistently alter total VFA concentration, but it did shift the VFA profile to higher acetate, lower propionate and lower butyrate molar proportions, consistent with less $CH_4$ production by all microbial fractions.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.9
• /
• pp.1280-1286
• /
• 2016

This study was aimed to evaluate the in vitro effects of medicinal herb extracts (MHEs) on ruminal fermentation characteristics and the inhibition of protozoa to reduce methane production in the rumen. A fistulated Hanwoo was used as a donor of rumen fluid. The MHEs (T1, Veratrum patulum; T2, Iris ensata var. spontanea; T3, Arisaema ringens; T4, Carduus crispus; T5, Pueraria thunbergiana) were added to the in vitro fermentation bottles containing the rumen fluid and medium. Total volatile fatty acid (tVFA), total gas production, gas profiles, and the ruminal microbe communities were measured. The tVFA concentration was increased or decreased as compared to the control, and there was a significant (p<0.05) difference after 24 h incubation. pH and ruminal disappearance of dry matter did not show significant difference. As the in vitro ruminal fermentation progressed, total gas production in added MHEs was increased, while the methane production was decreased compared to the control. In particular, Arisaema ringens extract led to decrease methane production by more than 43%. In addition, the result of real-time polymerase chain reaction indicted that the protozoa population in all added MHEs decreased more than that of the control. In conclusion, the results of this study indicated that MHEs could have properties that decrease ruminal methanogenesis by inhibiting protozoa species and might be promising feed additives for ruminants.

• Journal of Life Science
• /
• v.5 no.3
• /
• pp.126-136
• /
• 1995

The studies had been conducted to evaluate the grain processing effects for ruminants on starch digestion, body weight gain and feed efficiency since 1970. This research deals with experimental results on chemical structure, gelatinization, microbial starch digestion in rumen, intestinal starch digestion in rumen, roles of protozoa, intestinal starch digestion of bypass starch, limits to starch digestion in small intestine. The grain processing has different effects on digestion, weight gain and feed efficiency when different grain sources and contents is used, and the quality and quantity of roughage is different. The economical and efficient method of grain processing should be selected considering weight gain and feed efficiency enhancement than digestibility.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.11
• /
• pp.1580-1587
• /
• 2006

Several researchers have demonstrated that the rumen microbial community rapidly adapts to saponins and proposed interval feeding to prevent this rapid adaptation. An in vivo experiment was carried out to examine the effect of daily versus application every third day (interval feeding) of Sapindus rarak saponins (SE) on rumen fermentation end products, protozoal counts and nutrient digestibility. Thirty sheep were allocated into 5 groups. Sheep were fed daily or every third day with two levels of SE (0.48 and 0.72 g/kg body mass). One group received no saponin and served as control. All sheep received the same diet, a mixture of elephant grass and wheat pollard (65:35 w/w). Independent of the feeding regime and the level of inclusion, the addition of SE decreased protozoal counts and rumen ammonia concentrations (p<0.01). Microbial N supply and N retention were not affected by the high feeding regime. Daily feeding negatively influenced rumen xylanase and cellulase activity, but only when the high level of saponins was fed. However, these negative effects on rumen cell wall degradation were not reflected in decreasing total tract digestibility of the organic matter or the plant cell walls. Our results show that rumen microorganisms do not rapidly adapt to S. rarak saponins.

• Animal Bioscience
• /
• v.34 no.7
• /
• pp.1146-1156
• /
• 2021

Objective: The aim of the study was to compare the effect of two plant additives, rich in polyphenolic compounds, supplemented to sheep diets on microorganisms and carbohydrate fermentation in rumen. Methods: In the experiment, 6 ewes of the Polish Mountain breed were fitted with ruminal cannulas. Sheep were divided into three feeding groups. The study was performed in a cross-over design of two animals in each group, with three experimental periods (n = 6 per each group). The animals were fed a control diet (CON) or additionally received 3 g of dry and milled lingonberry leaves (VVI) or oak bark (QUE). Additionally, plant material was analyzed for tannins concentration. Results: Regardless of sampling time, QUE diet increased the number of total protozoa, as well as Entodinium spp., Diplodinium spp. and Isotrichidae family, while decreased bacterial mass. In turn, a reduced number of Diplodinium spp. and increased Ophryoscolex spp. population were noted in VVI fed sheep. During whole sampling time (0, 2, 4, and 8 h), the number of protozoa in ruminal fluid of QUE sheep was gradually reduced as opposed to animals receiving CON and VVI diet, where rapid shifts in the protozoa number were observed. Moreover, supplementing sheep with QUE diet increased molar proportions of butyrate and isoacids in ruminal fluid. Unfortunately, none of the tested additives affected gas production. Conclusion: The addition of VVI or QUE in a small dose to sheep diets differently affected rumen microorganisms and fermentation parameters, probably because of various contribution of catechins in tested plant materials. However, it is stated that QUE diet seems to create more favorable conditions for growth and development of ciliates. Nonetheless, the results of the present study showed that VVI and QUE additives could serve as potential natural modulators of microorganism populations and, consequently, carbohydrate digestion in ruminants.

• Journal of Animal Science and Technology
• /
• v.65 no.2
• /
• pp.387-400
• /
• 2023

Ruminal protozoa, especially entodiniomorphs, engulf other members of the rumen microbiome in large numbers; and they release oligopeptides and amino acids, which can be fermented to ammonia and volatile fatty acids (VFAs) by amino acid-fermenting bacteria (AAFB). Studies using defaunated (protozoa-free) sheep have demonstrated that ruminal protozoa considerably increase intraruminal nitrogen recycling but decrease nitrogen utilization efficiency in ruminants. However, direct interactions between ruminal protozoa and AAFB have not been demonstrated because of their inability to establish axenic cultures of any ruminal protozoan. Thus, this study was performed to evaluate the interaction between Entodinium caudatum, which is the most predominant rumen ciliate species, and an AAFB consortium in terms of feed degradation and ammonia production along with the microbial population shift of select bacterial species (Prevotella ruminicola, Clostridium aminophilum, and Peptostreptococcus anaerobius). From an Ent. caudatum culture that had been maintained by daily feeding and transfers every 3 or 4 days, the bacteria and methanogens loosely associated with Ent. caudatum cells were removed by filtration and washing. An AAFB consortium was established by repeated transfers and enrichment with casamino acids as the sole substrate. The cultures of Ent. caudatum alone (Ec) and AAFB alone (AAFB) and the co-culture of Ent. caudatum and AAFB (Ec + AAFB) were set up in three replicates and incubated at 39℃ for 72 h. The digestibility of dry matter (DM) and fiber (NDF), VFA profiles, ammonia concentrations, pH, and microscopic counts of Ent. caudatum were compared among the three cultures. The co-culture of AAFB and Ent. caudatum enhanced DM degradation, VFA production, and Ent. caudatum cell counts; conversely, it decreased acetate: propionate ratio although the total bacterial abundance was similar between Ec and the Ec + AAFB co-culture after 24 h incubation. The ammonia production and relative abundance of C. aminophilum and P. anaerobius did not differ between AAFB alone and the Ec + AAFB co-culture. Our results indicate that Ent. caudatum and AAFB could have a mutualistic interaction that benefited each other, but their interactions were complex and might not increase ammoniagenesis. Further research should examine how such interactions affect the population dynamics of AAFB.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.6
• /
• pp.885-893
• /
• 2001

This review summarizes some recent research into ways of improving the productivity of ruminal fermentation by increasing protein flow from the rumen and decreasing the breakdown of protein that results from the action of ruminal microorganisms. Proteinases derived from the plant seem to be of importance to the overall process of proteolysis in grazing animals. Thus, altering the expression of proteinases in grasses may be a way of improving their nutritive value for ruminants. Inhibiting rumen microbial activity in ammonia formation remains an important objective: new ways of inhibiting peptide and amino acid breakdown are described. Rumen protozoa cause much of the bacterial protein turnover which occurs in the rumen. The major impact of defaunation on N recycling in the sheep rumen is described. Alternatively, if the efficiency of microbial protein synthesis can be increased by judicious addition of certain individual amino acids, protein flow from ruminal fermentation may be increased. Proline may be a key amino acid for non-cellulolytic bacteria, while phenylalanine is important for cellulolytic species. Inhibiting rumen wall tissue breakdown appears to be an important mechanism by which the antibiotic, flavomycin, improves N retention in ruminants. A role for Fusobacterium necrophorum seems likely, and alternative methods for its regulation are required, since growth-promoting antibiotics will soon be banned in many countries.

• Journal of Life Science
• /
• v.22 no.10
• /
• pp.1324-1329
• /
• 2012

The objective of this study was to evaluate the in vitro effects of organic acids on methane emission and ruminal fermentation characteristics. We expected our methodology to result in a decrease of methanogens attached to the surface of rumen ciliate protozoa by addition of organic acids and in particular a decrease in methane emission. A fistulated Holstein cow of 650 kg body weight was used as a donor of rumen fluid. Organic acids (aspartic acid, fumaric acid, lactic acid, malic acid, and succinic acid) known to be propionate enhancers were added to an in vitro fermentation system and incubated with rumen fluid. The microbial population, including bacteria, protozoa, and fungi, were enumerated, and gas production, including methane and fermentation characteristics, were observed in vitro. Organic acids appeared to affect the rumen protozoan community. The rumen protozoal popuation decreased with the addition of aspartic acid, fumaric acid, lactic acid, and malic acid. In particular, the methane emission was reduced by addition of lactic acid. The concentration of propionate with all organic acids that were added appeared to be higher than that of the control at 12 h incubation. Addition of organic acids significantly affected rumen bacteria and microbial growth. The bacteria in added fumaric acid and malic acid was significantly higher (p<0.05) and protozoa was significantly lower (p<0.05) than that of the control. Microbial growth with the addition of organic acids was greater than the control after 48 h incubation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.10
• /
• pp.1482-1486
• /
• 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.

• Journal of Animal Science and Technology
• /
• v.65 no.3
• /
• pp.652-663
• /
• 2023

The rumen fluids contain a wide range of bacteria, protozoa, fungi, and viruses. The various ruminal microorganisms in the rumen provide nutrients by fermenting the forage they eat. During metabolic processes, microorganisms present in the rumen release diverse vesicles during the fermentation process. Therefore, in this study, we confirmed the function of rumen extracellular vesicles (EVs) and their interaction with the host. We confirmed the structure of the rumen EVs by transmission electron microscope (TEM) and the size of the particles using nanoparticle tracking analysis (NTA). Rumen EVs range in size from 100 nm to 400 nm and are composed of microvesicles, microparticles, and ectosomes. Using the Caenorhabditis elegans smart animal model, we verified the interaction between the host and rumen EVs. Exposure of C. elegans to rumen EVs did not significantly enhance longevity, whereas exposure to the pathogenic bacteria Escherichia coli O157:H7 and Staphylococcus aureus significantly increased lifespan. Furthermore, transcriptome analysis showed gene expression alterations in C. elegans exposed to rumen EVs, with significant changes in the metabolic pathway, fatty acid degradation, and biosynthesis of cofactors. Our study describes the effect of rumen EV interactions with the host and provides novel insights for discovering biotherapeutic agents in the animal industry.