Biomedical subjects

V H Varel

Publications and source records attributed to V H Varel.

At least 19 recordsLinked to original sources

PubMed2006

Incorporation of thymol into corncob granules for reduction of odor and pathogens in feedlot cattle waste.

Confined animal feeding operations can be a source of odor emissions, global warming gases, water pollution, and food contamination. Laboratory studies have indicated that plant oils with antimicrobial activity can be used to control pathogens and odor emissions from cattle and swine wastes. However, these oils are aromatic and may volatilize when applied topically. Our objectives were to evaluate the volatility of thymol from a feedlot surface and the effectiveness of topically applying thyme oil (2.5% thymol), incorporated into corncob granules and added once per week, to control odor emissions and total coliforms in feedlot manure. In the first study, thymol either volatilized or was degraded within 28 d after topical application. In a second study, thyme oil (2.5% thymol) was incorporated into corncobs and applied to pen surfaces weekly. Manure samples from 6 locations in each pen were collected from 3 untreated and 3 thymol-corncob-treated pens (15 x 150 m; fifty 400-kg cattle/pen), 3 times per week for 8 wk. Samples were analyzed for thymol concentration, total VFA, branched-chain VFA, aromatic compounds, and the number of Escherichia coli and total coliform bacteria. Over the 8 wk, with the exception of wk 7, the desired thymol concentration of 15 to 20 micromol/g DM was maintained in the manure. Concentrations of VFA and branched chain-VFA increased over time in untreated and treated pens. However, the rate of VFA accumulation in treated pens (7.5 +/- 1.3 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than the rate of accumulation in untreated pens (18.0 +/- 2.1 micromol.g DM(-1).wk(-1)). Likewise, the rate of branched-chain VFA accumulation in treated pens (0.31 +/- 0.04 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than in untreated pens (0.55 +/- 0.06 micromol.g DM(-1).wk(1)). The concentrations of E. coli in treated pens (2.9 +/- 1.2 x 10(5) cfu.g DM(-1)) were 91% less (P < 0.04) than in untreated pens (31.1 +/- 4.0 x 10(5) cfu.g DM(-1)). Similarly, concentrations of coliforms in treated pens (3.7 +/- 1.3 x 10(5) cfu.g DM(-1)) were 89% less (P < 0.04) than those of untreated pens (35.3 +/- 4.2 x 10(5) cfu.g DM(-1)). These results indicate that odor emissions and total coliforms can be reduced in feedlot manure with a once per week application of thymol incorporated in a granular form. However, corncobs are bulky, and other granular carriers with a greater carrying capacity for thyme oil should be explored.

Animal Husbandry↗

PubMed2005

Effects of common forage phenolic acids on Escherichia coli O157:H7 viability in bovine feces.

Ruminant animals are carriers of Escherichia coli O157:H7, and the transmission of E. coli O157:H7 from cattle to the environment and to humans is a concern. It is unclear if diet can influence the survivability of E. coli O157:H7 in the gastrointestinal system or in feces in the environment. Feces from cattle fed bromegrass hay or corn silage diets were inoculated with E. coli O157:H7, and the survival of this pathogen was analyzed. When animals consumed bromegrass hay for <1 month, viable E. coli O157:H7 was not recovered after 28 days postinoculation, but when animals consumed the diet for >1 month, E. coli O157:H7 cells were recovered for >120 days. Viable E. coli O157:H7 cells in feces from animals fed corn silage were detected until day 45 and differed little with the time on the diet. To determine if forage phenolic acids affected the viability of E. coli O157:H7, feces from animals fed corn silage or cracked corn were amended with common forage phenolic acids. When 0.5% trans-cinnamic acid or 0.5% para-coumaric acid was added to feces from silage-fed animals, the E. coli O157:H7 death rate was increased significantly (17-fold and 23-fold, respectively) compared to that with no addition. In feces from animals fed cracked corn, E. coli O157:H7 death rates were increased significantly with the addition of 0.1% and 0.5% trans-cinnamic acid (7- and 13-fold), 0.1% and 0.5% p-coumaric acid (3- and 8-fold), and 0.5% ferulic acid (3-fold). These data suggest that phenolic acids common to forage plants can decrease viable counts of E. coli O157:H7 shed in feces.

Animal Feed↗

PubMed2004

Eugenol stimulates lactate accumulation yet inhibits volatile fatty acid production and eliminates coliform bacteria in cattle and swine waste.

AIM: To determine how eugenol affects fermentation parameters and faecal coliforms in cattle and swine waste slurries stored anaerobically. METHODS AND RESULTS: Waste slurries (faeces:urine:water, 50:35:15) were blended with and without additives and aliquoted to triplicate 1-l flasks. Faecal coliforms were eliminated in cattle and swine waste slurries within 1 or 2 days with additions of eugenol at 10.05 mm (0.15%) and 16.75 mm (0.25%). At these concentrations volatile fatty acids (VFA) were reduced ca 70 and 50% in cattle and swine waste, respectively, over 6-8 weeks. Additionally, in cattle waste, eugenol stimulated the accumulation of lactate (>180 mm) when compared with thymol treatment (20 mm lactate). In swine waste, lactate accumulation did not occur without additives; eugenol and thymol stimulated lactate accumulation to concentrations of 22 and 32 mm, respectively. CONCLUSIONS: Eugenol added to cattle waste may be more beneficial than thymol because not only does it effectively control faecal coliforms and odour (VFA production), it also stimulates lactate accumulation. This in turn, causes the pH to drop more rapidly, further inhibiting microbial activity and nutrient emissions. SIGNIFICANCE AND IMPACT OF THE STUDY: Plant essential oils have the potential to solve some of the environmental problems associated with consolidated animal feeding operations. Thymol and eugenol reduce fermentative activity, thus, have the potential to reduce emissions of greenhouse gases and odour, and curtail transmission of pathogens in cattle and swine wastes.

Animals↗

PubMed2004

Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet.

Four Duroc x White composite crossbred (21.8 +/- 1.0 kg BW) and four 12-wk-old Meishan purebred (20.7 +/- 1.6 kg BW) growing barrows were used to determine the relative breed differences in metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume 700 g of a diet containing 35% (as-fed basis) dehydrated alfalfa meal once daily. The pigs' daily intakes of DM, N, GE, NDF, and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery, a 3-d total urine and feces collection was conducted. On d 24 after surgery, each pig was placed in an open-circuit calorimeter, and its catheters were connected to a system for simultaneous measurements of oxygen consumption by portal-drained viscera and by whole body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 after surgery. There were no differences (P = 0.13) between the first and second collections in apparent total-tract digestibility coefficients for nutrients and N retention of pigs. Compared with Duroc x White composite crossbred pigs, Meishan pigs had lower (P = 0.05) apparent digestibility coefficients for DM, N, NDF, hemicellulose, and N retention, but their portal-drained viscera used a greater (P = 0.05) fraction of whole-body oxygen consumption. No differences (P = 0.12) were found between Duroc x White composite crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting the energy needs for whole-body heat production. These results indicate that, in contrast to previous beliefs, the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.

Animal Feed↗

PubMed2004

Plant oils thymol and eugenol affect cattle and swine waste emissions differently.

Wastes generated from the production of cattle and swine in confined facilities create the potential for surface and groundwater pollution, emission of greenhouse gases, transmission of pathogens to food and water sources, and odor. It is our hypothesis that something which inhibits microbial fermentation in livestock wastes will be beneficial to solving some of the environmental problems. Our work has concentrated on the use of antimicrobial plant oils, thymol, thyme oil, carvacrol, eugenol and clove oil. Anaerobic one-litre flasks with a working volume of 0.5 L cattle or swine manure were used to evaluate the effect of thymol and eugenol on production of fermentation gas, short-chain volatile fatty acids, lactate, and bacterial populations. Either oil at 0.2% in both wastes essentially stopped all production of gas and volatile fatty acids, and eliminated all fecal coliform bacteria. In cattle but not swine waste, thymol prevented the accumulation of lactate. However, eugenol stimulated lactate formation in cattle and swine wastes. Thus, eugenol may offer a distinct advantage over thymol, because lactate accumulation in the wastes causes the pH to drop more rapidly, further inhibiting microbial activity and nutrient emissions. We conclude that plant oils may offer solutions to controlling various environmental problems associated with livestock wastes, assuming that they are cost-effective.

Animals↗

PubMed2003

Swine manure composition affects the biochemical origins, composition, and accumulation of odorous compounds.

Odors from swine production facilities are associated with the storage and decomposition of manure. Diet is linked to manure composition and will likely affect odor, but the microbial mechanisms responsible for manure decomposition and odor production are poorly understood. To identify the sources of odor during manure fermentation, substrates (starch, casein, and cellulose) were added to slurries of fresh swine manure, and the anaerobic accumulation of fermentation products and the consumption of substrates were measured relative to no addition of substrates. Volatile fatty acids and alcohols were the dominant fermentation products in all treatments. The total VFA concentration from starch treatment was greater (P < 0.001) than for all other treatments. Branched-chain VFA and aromatic compounds accumulated in all treatments, but accumulation in the casein treatments was greater (P < 0.001) than in all other treatments. Thus, addition of carbohydrate to swine manure slurries did not circumvent protein fermentation, as was previously observed in cattle manure slurries. Based on substrate loss, starch and protein fermentation were equivalent in all treatments, with losses of each exceeding 4% of the DM. Substrate additions had a limited effect on the overall accumulation of odor compounds in manure and on odor compound composition. Compared with the results of the earlier fermentation study of fresh cattle manure, swine manure fermentation produced less lactate and more products of protein fermentation (branched-chain VFA and aromatic ring compounds). We hypothesize that differences in manure organic matter composition between cattle and swine, a result of diet and digestion, select for bacterial communities that are adapted to the available substrate composition.

Animal Feed↗

PubMed2002

An in vitro study of manure composition on the biochemical origins, composition, and accumulation of odorous compounds in cattle feedlots.

Very little is known about the biochemical origin of cattle feedlot odors and the environmental factors controlling their production. The tie between diet and manure composition is well established, but the effect of different manure compositions on odorous chemical production is unknown. This study describes the effect of starch, casein, and cellulose substrate additions to slurries of fresh (< 24 h) and aged cattle manure (> 1 d) on the anaerobic production of fermentation products and the consumption of substrates relative to no addition treatments. Aged cattle manure accumulated more VFA (245 to 290 mM) than the fresh manure (91 to 181 mM) irrespective of substrate additions (P < 0.001). In fresh manures, VFA concentrations were increased (P < 0.01) over no addition treatments when carbohydrate (starch or cellulose) was added, whereas starch and protein treatments to aged manure increased VFA content relative to no addition treatments (P < 0.001). Branched-chain VFA and aromatic compounds accumulated only in the aged manure (no addition and protein treatments), indicating that some protein fermentation occurred in those treatments. Based upon substrate loss, starch fermentation was the dominant process in both manures and all treatments with losses exceeding 18.6 g/L. Protein fermentation occurred only in the aged manure, specifically the no addition and protein treatments, when starch was no longer available. The production of odorous compounds from manure was controlled by substrate availability and pH, with pH related to lactate accumulation. We believe that calcareous soil and lactate-consuming microorganisms in the aged manure slurries minimized slurry acidification and resulted in greater accumulations of odorous products. Substrate additions had little effect on the overall accumulation of odor compounds in manure but had profound effects on odor compound composition. We propose that modifying cattle diets to limit starch and protein excretion would profoundly affect the production and accumulation of odor compounds in feedlots.

Animals↗

PubMed2001

Plant-derived oils reduce pathogens and gaseous emissions from stored cattle waste.

Carvacrol and thymol in combination at 6.7 mM each completely inhibited the production of short-chain volatile fatty acids and lactate from cattle waste in anoxic flasks over 23 days. Fecal coliforms were reduced from 4.6 x 10(6) to 2.0 x 10(3) cells per ml 2 days after treatment and were nondetectable within 4 days. Total anaerobic bacteria were reduced from 8.4 x 10(10) to 1.5 x 10(7) cells per ml after 2 days and continued to be suppressed to that level after 14 days. If the concentration of carvacrol or thymol were doubled (13.3 mM), either could be used to obtain the same inhibitory fermentation effect. We conclude that carvacrol or thymol may be useful as an antimicrobial chemical to control pathogens and odor in stored livestock waste.

Animals↗

PubMed2001

In vitro study of the biochemical origin and production limits of odorous compounds in cattle feedlots.

Livestock odors are closely correlated to airborne concentrations of volatile organic compounds (VOC), which are a complex mixture of carbon-, sulfur-, and nitrogen-containing compounds produced primarily during the incomplete anaerobic fermentation of animal manure by microorganisms. Volatile fatty acids, alcohols, and aromatic ring compounds comprise a substantial fraction of VOC, yet very little is known about their biochemical origin and environmental factors controlling their production. The anaerobic production of fermentation products and consumption of substrates (CP, starch, and nonstarch carbohydrate) were analyzed in slurries of fresh (< 24 h) and aged (> 1 d) cattle manure over several weeks. Ethanol, acetate, propionate, butyrate, lactate, and H2 were the major products of fermentation. Aged cattle manure produced twice the concentration of VFA during incubation produced by the fresh manure (P < 0.001). Aromatic compounds (phenols, indoles, and benzoates) remained unchanged in both manures. Production of VFA from fresh manure was inhibited when the pH fell below 4.5. It is likely that the presence of calcareous soil, which has a high buffering capacity, and lactate-consuming microorganisms minimized acidification in the aged manure slurries. Low starch content limited VFA production in the aged manure. Starch was the likely biochemical source for fermentation products in both manures based on the strong negative correlations between fermentation product and starch content (r = -0.944 and -0.773) and ratio of fermentation products produced to starch consumed (r = 0.64 and 0.72) for fresh and aged manure, respectively. Nonstarch carbohydrate served an indeterminate role in the production of fermentation products. Nonstarch carbohydrate decreased by 4.7 and 23.4 g/L in the fresh and aged manure, respectively, whereas the starch content decreased by 18.6 and 22.4 g/L in the fresh and aged manure, respectively. The concentration of CP did not change, which suggests a balance between protein consumption and new bacterial biomass production. We conclude that the types of substrates in cattle manure and the feedlot soils where they are deposited are significant factors in the production of odors.

Animals↗

PubMed2001

Effect of carvacrol and thymol on odor emissions from livestock wastes.

A majority of the beef cattle and swine in the United States is produced in confined facilities. This generates significant environmental pollutants from the waste produced, including global warming gases, odor, and pathogens. The objectives of this study were to control the fermentation activity and pathogens in cattle and swine wastes with antimicrobial plant essential oils. Anaerobic one litre flasks with a working volume of 0.5 l were used to evaluate the effect of carvacrol and thymol on production of fermentation gas, short-chain volatile fatty acids, lactate, and bacterial populations. In cattle waste, 1 g l(-1) each of carvacrol and thymol completely inhibited the production of volatile fatty acids and lactate over 23 days. In swine waste, 2.5 g l(-1) carvacrol inhibited the production of all volatile fatty acids. We conclude that these essential oils are effective in controlling livestock waste odor emissions and field studies are warranted.

Air Pollution↗

PubMed2000

Effect of antimicrobial agents on livestock waste emissions.

Various antimicrobial agents were evaluated with the purpose of reducing the microbial fermentation in stored cattle waste and the resulting odor emissions. Duplicate sealed 2-L flasks with 500 ml waste slurry, with and without antimicrobial inhibitors, were used to measure the production of short-chain volatile fatty acids, lactate, and total fermentation gas over 27-30 days. A combination of chlorhexidine diacetate (2 mM), iodoacetate (2 mM), and alpha-pinene (3.8 mM) reduced gas production 80% (1000 ml to 200 ml) and total volatile fatty acid production 50% (145 mM to 72 mM). Pinene had little antimicrobial effect; rather, it served as an effective masking agent, giving the waste a less offensive odor. A combination of chlorhexidine diacetate and the deaminase inhibitor, diphenyliodonium chloride (1.3 mM) had a similar effect in reducing short-chain volatile fatty acid production (145 mM to 80 mM). It is concluded that a combination of antimicrobial agents may be useful in controlling odor emissions and conserving organic matter in livestock wastes, therefore providing a potentially more useful byproduct waste when used as plant fertilizer.

Animals↗

PubMed1999

Accuracy of Klason lignin and acid detergent lignin methods as assessed by bomb calorimetry.

An accurate method for estimation of lignin concentration is important for prediction of the digestible energy content of livestock feeds. The accuracy of lignin concentration estimates based on the Klason lignin and acid detergent lignin methods was compared. Ten diverse forage samples were analyzed for protein, carbohydrates, lipids, organic acids, ash, lignin (by both methods), and gross energy. The accuracy of the two lignin concentration estimates was examined by comparing the measured forage gross energy to a gross energy value calculated from the compositional analysis. Use of the acid detergent lignin estimate in this gross energy calculation accounted for 68-84% of the forage gross energy compared to 85-97% of the gross energy using Klason lignin. These results indicate that while Klason lignin estimates are substantially higher than acid detergent lignin estimates, Klason lignin is the more accurate lignin method and does not overestimate lignin because gross energy recoveries were less than 100%.

Animal Feed↗

PubMed1999

Low- and high-quality forage utilization by heifers and mature beef cows.

Eight cows (7 to 9 yr old, 522 kg) and six heifers (10 mo old, 169 kg) were fed either alfalfa hay (18.7% CP) or mature brome hay (5.1% CP) to determine the effect of cattle age on apparent forage utilization. Cattle were fitted with ruminal and duodenal cannulas and were individually fed once daily (ad libitum intake, 1000). The split-plot design consisted of age (whole-plot) and two sampling periods feeding alfalfa or brome hay (subplot). Each period consisted of 28 d: d 1 to 13 for adaptation, d 13 to 20 for feed intake determination, and d 20 to 28 for sampling. Nylon bags containing NDF substrate from alfalfa or brome hay were incubated ruminally for 0, 3, 6, 12, 24, 48, 96, and 192 h to determine the rate and extent of fiber degradation. Ruminal liquid dilution rate and fermentation characteristics were conducted on d 27. Ruminal fill was determined by total evacuation at 0800 on d 28. Cows consumed more feed (BW.75; P<.01) and had greater ruminal OM fill (P = .04) but had similar fluid fill (P = .88) compared with heifers. Ruminal liquid dilution rate was greater in cows than in heifers (P<.01). The rate of in situ NDF degradation was 3 and .5% per hour greater in cows than in heifers when alfalfa and brome hay were fed, respectively (age x hay, P<.01). Ruminal NDF digestibility as a percentage of intake was greater in cows than in heifers (P<.01). Numbers of ruminal cellulolytic bacteria were not affected by treatment (P>.21). These data indicate that mature cows have a smaller ruminal fluid fill that turns over more rapidly, and this may be responsible for a faster rate of ruminal fiber degradation in cows than in young heifers.

Aging↗

PubMed1999

Conservation of nitrogen in cattle feedlot waste with urease inhibitors.

Feedlot cattle normally retain less than 20% of their dietary nitrogen intake. Sixty to 80% of the nitrogen excreted is normally lost through volatilization of ammonia, which is primarily generated from urea. This loss of ammonia nitrogen pollutes the environment and creates an unfavorable ratio of nitrogen to phosphorous (N:P) in the waste for crop growth. Two urease inhibitors, cyclohexylphosphoric triamide (CHPT) and N-(n-butyl) thiophosphoric triamide (NBPT) were evaluated for their ability to reduce the rate of urea hydrolysis in beef cattle feedlot pens. Initially, a total of six pens were used, two pens per treatment, with approximately 70 cattle per pen, and a single topical application of CHPT or NBPT at 20 mg/kg of manure. Essentially no urea was found in untreated pens. However, with CHPT treatment, 2 g of urea/kg of dry manure accumulated by d 4, and all gradually disappeared by d 11; NBPT conserved 3 and 3.5 g of urea/kg by d 4 and 9, respectively, and it had disappeared by d 14 (treatment [trt] x day, P = .003). A second study involved application of NBPT weekly for 6 wk. This caused urea to accumulate to a peak concentration of 17 g/kg of manure by d 30 (trt x day2, P = .001). Once the treatment was stopped the urea concentration began to decrease. When the NBPT was applied weekly, the concentration of ammonia in the waste was less for the treated pens (trt x day, P = .01), the total nitrogen was greater (trt x day, P = .04), pH tended to be lower (trt x day, P = .10), and the total volatile acids were not different (trt x day, P = .51) from untreated pens. We concluded that urease inhibitors could be used to control ammonia emissions from animal wastes, prevent environmental damage, and produce a more balanced (N:P) fertilizer from manure.

Animals↗

PubMed1998

Conjugal transfer of transposon Tn1545 into the cellulolytic bacterium Eubacterium cellulosolvens.

Tn1545, a self-mobilizing transposon, was introduced into the chromosome of the ruminal cellulolytic bacterium Eubacterium cellulosolvens. This was achieved by conjugal transfer of the transposon from Clostridium beijerinckii at a frequency of 1 per 10(6) recipient cells. Transconjugants of Eu. cellulosolvens were resistant to both tetracycline and erythromycin, and were able to mobilize Tn1545 back into Cl. beijerinckii. Southern blot hybridization of representative transconjugants did not reveal site-specific insertion. This potential randomness of the transposon insertion site may prove useful in the development of Tn1545 as a tool for mutagenesis of Eu. cellulosolvens.

Animals↗

PubMed1998

Biochemical identification and biological origin of key odor components in livestock waste.

Animal production results in conversion of feeds into valuable products such as meat, milk, eggs, and wool as well as into unavoidable and less desirable waste products. Intensification of animal numbers and increasing urbanization has resulted in considerable attention to odorous gases produced from animal wastes. It is clear that animal manure was, and still is, a valuable resource. However, it may be a major obstacle to future development of the animal industry if its impact on the environment is not properly controlled. Poor odor prevention and control from animal wastes is related to a lack of knowledge of the fundamental nature of odor and its production by farm animals. Odor, like noise, is a nuisance or disturbance and there is no universally accepted definition of an objectionable odor. Thus, regulation and control of odors in the environment is difficult because of the technical difficulties of defining odor limits and their measurement and evaluation. A variety of direct (sensory) and indirect (analytical instruments) methods for measuring odor intensity and determination of individual or key odor components are discussed. The biological origins of the four principal classes of odor compounds, namely branched- and straight-chain VFA, ammonia and volatile amines, indoles and phenols, and the volatile sulfur-containing compounds, are reviewed. Because more than 50% of N from animals is excreted as urea, one strategy to conserve N in waste is to inhibit the urease enzyme that converts urea to ammonia. Laboratory studies to evaluate di- and triamide compounds to control urea hydrolysis in slurries of cattle and swine wastes are presented. Finally, a brief overview of various intervention strategies is provided. Multiple combinations of nutritional management, housing systems, treatment options as well as storage and disposal of animal wastes will be required to reduce environmental pollution and provide for long-term sustainable growth.

Amino Acids↗

PubMed1997

Microbial perspective on fiber utilization by swine.

Dietary fiber may contribute up to 30% of the maintenance energy needs of growing pigs. Higher energy contributions may be obtained from dietary fiber fed to sows, along with some improvements in reproduction, health, and well-being. As long as cereal grain supplies and high-quality protein supplements are abundant, the use of fibrous feeds for swine most likely will be limited. However, as the human demand for cereal grains increases, swine producers, especially those with reproductive animals, may be economically forced to incorporate alternative feedstuffs. These feedstuffs might include lignified plant cell wall material such as grasses and legumes, and feed-milling and distillery by-products that contain a high level of fiber residues. The microflora in swine large intestine will be able to adapt to these lignified forages and by-product feeds much better than the microflora in humans. Swine microflora contain highly active ruminal cellulolytic and hemicellulolytic bacterial species, which include Fibrobacter succinogenes (intestinalis), Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio spp., and Prevotella ruminicola. Additionally, a new highly active cellulolytic bacterium, Clostridium herbivorans, has been recently isolated from pig large intestine. The populations of these microorganisms are known to increase in response to the ingestion of diets high in plant cell wall material. The numbers of cellulolytic bacteria from adult animals are approximately 6.7 times greater than those found in growing pigs. None of these highly active cellulolytic bacterial species are found in the human large intestine. Thus, the pig large intestinal fermentation of fiber seems to more closely resemble that of ruminants than that of humans.

Animals↗

PubMed1995

Clostridium herbivorans sp. nov., a cellulolytic anaerobe from the pig intestine.

A new cellulolytic anaerobic clostridium was isolated from the intestinal tract of pigs. The single isolate was a gram-positive, motile rod, formed terminal to subterminal swollen sporangia, and required a fermentable carbohydrate for growth. Cellulose, cellobiose, maltose, starch, and glycogen supported growth, but glucose and fructose did not. The major end products from the fermentation of cellobiose were butyrate and formate; minor amounts of hydrogen and ethanol were also formed. Ruminal fluid (15%) or yeast extract (1%) was required for good growth. The optimum temperature for growth was 39 to 42 degrees C, and the optimum pH was 6.8 to 7.2. Cell lysis occurred rapidly once stationary growth was reached. A 16S rRNA sequence analysis showed that the strain was related to a group of gram-positive anaerobes that includes Clostridium oroticum and the cellulolytic species Clostridium polysaccharolyticum and Clostridium populeti. The DNA base composition of the isolate is 38 mol% G + C. We propose the name Clostridium herbivorans for this organism; strain 54408 (= ATCC 49925) is the type strain.

Anaerobiosis↗