The relationship between methane production and concentrations of hydrogen in the aqueous and gaseous phases during rumen fermentation in vitro.
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Animals↗
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Results for “In vitro fermentation”
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Starch and fiber fractions in selected food and feed ingredients affect their small intestinal digestibility and fermentability and their large bowel fermentability in vitro in a canine model.
The digestion of legumes, cereal grains, cereal and potato flours and grain-based foods in dogs was studied using two in vitro model systems. The first simulated the stomach and small intestine through the additions of acid and enzymes and large bowel fermentation through use of fecal inocula from dogs, and the second simulated small intestinal fermentation using canine ileal chyme as the bacterial source. All substrates were analyzed for total dietary fiber (TDF) including insoluble and soluble components, and starch fractions: rapidly digestible starch, slowly digestible starch, resistant starch (RS) and total starch. Legumes had high TDF and RS concentrations (mean 36.5 and 24.7%, respectively), resulting in lower ileal digestible starch and total digestible starch concentrations (mean 21 and 31%, respectively). Seventy-four percent of the TS in the cereal grains group was rapidly digestible starch plus slowly digestible starch compared with the flour group, where the corresponding value was 95%. This related to the processing of cereals to flours, in which TDF and RS concentrations were reduced markedly. This increased ileal digestible starch concentrations in the flour group (65%) versus the cereal grains group (60%). Ileal digestion of starch in grain-based food products like macaroni and spaghetti was high (96 and 92%, expressed as a percentage of TS, respectively). Fermentation of substrates with ileal microflora was influenced by substrate chemical composition, with the flour group exhibiting the highest organic matter disappearance values. The legume group had a high total short-chain fatty acid concentration (7.8 mmol/g organic matter fermented), perhaps as a result of fermentation of TDF as well as starch components. A database such as this one provides information about utilization of foods and feeds in the dog and potentially in humans.
Animals↗
Incorporation of soya oil hydrolysate in the diet of defaunated or refaunated sheep: effect on rumen fermentation in vitro.
The effects of incorporation in the diet of 7% soya oil hydrolysate (SOH) on in vitro incubations of cellobiose + maltose, maize starch and casein by rumen microbes were studied using defaunated and refaunated sheep as rumen fluid donors. Feeding refaunated sheep the SOH supplemented diet lowered the protozoal numbers in the rumen from 1.61 10(6)/ml to 6.1 10(5)/ml. SOH addition reduced in vitro methane production, rather by a depletion of methanogens is than by a simple inhibition of their activity. This reduction seemed to be independent of protozoa depletion. With cellobiose-maltose and maize starch incubations, SOH supplementation increased molar proportion of propionate while acetate decreased. Both variations could be linked to the inhibition of methanogenesis. Volatile fatty acid production from casein was strongly reduced by SOH supplementation with or without protozoa in the rumen of the donors animals.
Animal Feed↗
Propionate precursors and other metabolic intermediates as possible alternative electron acceptors to methanogenesis in ruminal fermentation in vitro.
Fifteen potential precursors of propionate were tested for their ability to decrease CH4 production by ruminal fluid in vitro. Sodium acrylate and sodium fumarate produced the most consistent effects in batch cultures, with 50 % of the added precursors being fermented to propionate and CH4 production decreasing by between 8 and 17 %, respectively. Additives were more effective when added as free acids, but this also decreased the pH and may have inhibited fibre digestion. Changing the dietary substrate from predominantly grass hay to predominantly concentrate had no influence on the effectiveness of acrylate and fumarate. In an in vitro fermentor (the rumen simulating technique, Rusitec) with a grass hay-concentrate (50:50, w/w) diet as substrate, both compounds were again fermented to propionate (33 and 44 % conversion to propionate, respectively). However, fumarate appeared more effective as a H2 sink compound. It was calculated to capture 44 % of the H2 previously used for CH4 formation compared with a 22 % capture of H2 with acrylate. Fumarate also caused a stimulation in fibre digestion. Thus, sodium fumarate was the preferred propionate precursor for use as a feed ingredient to decrease CH4 emissions from ruminants.
Acids↗
Estimating diet digestibility: a comparison of 11 techniques across six different diets fed to rams.
Six digestion trials were conducted using eight Suffolk rams (four/trial; two trials run concurrently) to determine the ability of 11 techniques to estimate in vivo apparent DM digestibility (DMD). Diets (trials) were as follows: 1) ad libitum access to chopped fescue hay, 2) ad libitum access to alfalfa hay, 3) limit-fed fescue hay, 4) limit-fed alfalfa hay, 5) 25% soybean meal and 75% fescue hay and 6) 40% rolled corn and 60% alfalfa hay. Total feces were collected for 7 d following a 21-d adaptation to each diet. Digestibility methods evaluated were the following: 1) in vitro disappearance (INVITRO); 2) 48 h and 3) 72 h in situ nylon bag (48NB, 72NB); 4) 48NB followed by a 48-h acid pepsin digestion; 5) 96 h and 6) 144 h in vitro fermentation followed by NDF analysis (INDF96 and INDF144) 7) 96 h and 8) 144 h in vitro fermentation followed by ADF analysis (IADF96 and IADF144); 9) ADL ratio; 10) alkaline hydrogen peroxide treatment before ADL analysis (APFPRE) and 11) alkaline hydrogen peroxide treatment after ADF extraction of ADL (ADLPST). Apparent in vivo DMD was accurately estimated (P greater than .10) by INVITRO, ADL and APLPST with Diet 1. However no marker accurately estimated in vivo DMD when fescue was limit-fed. Apparent DMD of Diet 2 was accurately predicted (P greater than .10) by INVITRO, but when Diet 2 was limit-fed, only 48NB and 72NB predicted (P greater than .10) DMD accurately. In vivo DMD coefficients for Diet 5 followed a pattern similar to that of Diet 1. Diet 6 was predicted by INVITRO, 48NB, INDF96, INDF144 and IADF96 (P greater than .10). Results suggest that caution should be exercised when using these techniques, because no single technique provided accurate estimates across all diets and feeding conditions.
Analysis of Variance↗
Attempted induction of reductive acetogenesis into the rumen fermentation in vitro.
Rumen and caecal contents, obtained from slaughterhouse cattle and rumen contents obtained from a fistulated wether were incubated in vitro with ground hay in the presence and absence of, respectively, casein hydrolysate and mucin. Differences in stoichiometry of rumen and caecal fermentations, indicative of reductive acetogenesis in the caecum, were confirmed, except for incubations with free amino acids. Net fermentation end product production was determined after correction for amounts formed in incubations without the substrate. These determined amounts of hay fermentation end products were compared with the amounts calculated from incubations of hay with added casein hydrolysate or mucin, corrected for amounts formed from the latter added substrates incubated alone. With casein hydrolysate, no differences between the determined and calculated amounts were observed, excluding the occurrence of reductive acetogenesis from hay in the presence of free amino acids. With mucin, the calculated amounts indicated an inhibition of methanogenesis, accompanied by increased amounts of proprionate, butyrate and valerate production. This finding was probably related to the greater availability of easily fermented carbohydrates in the presence of mucins. The absence of an increased acetate production in the incubations with added head space hydrogen gas, also indicate the absence of reductive acetogenesis from hay in the presence of mucin. Stoichiometric considerations also indicate that neither free amino acids, nor mucin, induce reductive acetogenesis in short-term in vitro incubations of rumen contents with hay.
Acetates↗
Metabolic inhibitor(s) in fractions of orchardgrass (Dactylis glomerata L.) detected by in vitro rumen fermentation technique.
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Animals↗
Tannins in tropical browses: effects on in vitro microbial fermentation and microbial protein synthesis in media containing different amounts of nitrogen.
Four species of browses (Acacia angustissima, Acacia salicina, Calliandra calothyrsus, andDichrostachys cinerea) were used to study the effect of tannins on microbial fermentation and microbial protein synthesis in incubation media containing high nitrogen (HN) and low nitrogen (LN) in the presence and absence of polyethylene glycol (PEG, MW 6000). The additional nitrogen in HN medium was supplied through ammonium bicarbonate. The use of HN medium significantly (P < 0.05) increased the in vitro gas and short-chain fatty acid (SCFA) production and microbial protein synthesis compared to the LN medium. Incubation of tannin-containing browses alone produced significantly (P < 0.05) lower gas and SCFA compared to in the presence of PEG in both HN and LN media. Inclusion of PEG in tannin-containing browses significantly (P < 0.05) reduced the molar proportion of propionate compared to in its absence. Higher N in the media resulted in 10.4 and 9.9% increases in in vitro gas and SCFA production, respectively, whereas inclusion of PEG to tannin-containing feed to remove the effect of tannins increased the in vitro gas and SCFA production by 186 and 195%, respectively, indicating that the low fermentation of tannin-containing browses could be due to the depressive effects of tannins on microbial activity and only partially accounted for by unavailability of N for rumen microbes. Incubation of browses with straw significantly (P < 0.05) decreased ammonia nitrogen concentration but increased the in vitro gas and SCFA production and microbial protein synthesis compared to straw alone.
Bacterial Proteins↗
In vitro investigation into the potential prebiotic activity of honey oligosaccharides.
The effect of honey oligosaccharides on the growth of fecal bacteria was studied using an in vitro fermentation system. Prior to treatment, glucose and fructose (31.73 and 21.41 g/100 g of product, respectively) present in honey, which would be digested in the upper gut, were removed to avoid any influence on bacterial populations in the fermentations. Nanofiltration, yeast (Saccharomyces cerevisiae) treatment, and adsorption onto activated charcoal were used to remove monosaccharides. Prebiotic (microbial fermentation) activities of the three honey oligosaccharide fractions and the honey sample were studied and compared with fructooligosaccharide (FOS), using 1% (w/v) fecal bacteria in an in vitro fermentation system (10 mg of carbohydrate, 1.0 mL of basal medium). A prebiotic index (PI) was calculated for each carbohydrate source. Honey oligosaccharides seem to present potential prebiotic activity (PI values between 3.38 and 4.24), increasing the populations of bifidobacteria and lactobacilli, although not to the levels of FOS (PI of 6.89).
Bacteria↗
Short-chain fructooligosaccharides, in spite of being fermented in the upper part of the large intestine, have anti-inflammatory activity in the TNBS model of colitis.
Previous studies have demonstrated the anti-inflammatory effect of fructooligosaccharides (FOS) on intestinal inflammation. The aim of the present study was to elucidate whether the colonic fermentation of these carbohydrates is a pre-requisite for this anti-inflammatory activity.With this aim short chain-FOS (SC-FOS) were used for an in vitro fermentation to elucidate the time of fermentation of these compounds. For the in vivo experiments female Wistar rats were fed several diets with different sources of fibre (5 g/kg): cellulose for control rats (n = 30) or SC-FOS (n = 20) with a high content of kestose (GF(2)) for the SC-FOS group. After one month of feeding the different diets 10 rats from each group were sacrificed to analyze cecal and colonic microflora, SCFA production and pH of intestinal contents. A distal colonic inflammation was induced to other 10 rats from each group by the administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol (v/v). The rest of the rats from the control group (n = 10) were rendered healthy. One week after TNBS treatment rats were sacrificed and several inflammatory parameters as well as intestinal microbiota and SCFA contents were analyzed. In vitro fermentation experiments showed that SC-FOS are fermented during the first 12 h after incorporating the oligosaccharides to intestinal contents, thus suggesting a preferential fermentation of these carbohydrates in the ileum and cecum. In fact, SC-FOS increased cecal lactobacilli and bifidobacteria counts as well as SCFA production in healthy rats. In colitic rats, SC-FOS feeding caused a decrease of MPO activity, leukotriene B4 (LTB4) production and iNOS expression. This anti-inflammatory effect was evidenced macroscopically by a significant reduction in the extent of colonic damage. SC-FOS also promoted a more favorable intestinal microbiota, increasing lactobacilli and bifidobacteria counts. In conclusion, although oligosaccharides are preferentially fermented in the upper parts of the large intestine, its prebiotic effect is extended to the distal colonic segments, thus exerting a positive effect on colonic inflammation.
Animals↗
Inhibition of ruminal cellulose fermentation by extracts of the perennial legume cicer milkvetch (Astragalus cicer).
Cicer milkvetch (Astragalus cicer L.) is a perennial legume used as a pasture or rangeland plant for ruminants. A study was undertaken to determine whether reported variations in its ruminal digestibility may be related to the presence of an antinutritive material. In vitro fermentation of neutral detergent fiber (NDF) of cicer milkvetch by mixed rumen microflora was poorer than was the fermentation of NDF in alfalfa (Medicago sativa L.). Fermentation of cicer milkvetch NDF was improved by preextraction of the ground herbage with water for 3 h at 39 degrees C. Such water extracts selectively inhibited in vitro fermentation of pure cellulose by mixed ruminal microflora and by pure cultures of the ruminal bacteria Ruminococcus flavefaciens FD-1 and Fibrobacter succinogenes S85. Inhibition of the cellulose fermentation by mixed ruminal microflora was dependent upon the concentration of cicer milkvetch extract and was overcome upon prolonged incubation. Pure cultures exposed to the extract did not recover from inhibition, even after long incubation times, unless the inhibitory agent was removed (viz., by dilution of inhibited cultures into fresh medium). The extract did not affect the fermentation of cellobiose by R. flavefaciens but did cause some inhibition of cellobiose fermentation by F. succinogenes. Moreover, the extracts did not inhibit hydrolysis of crystalline cellulose, carboxymethyl cellulose, or p-nitrophenylcellobioside by supernatants of these pure cultures of cellulolytic bacteria or by a commercial cellulase preparation from the fungus Trichoderma reesei. The agent caused cellulose-adherent cells to detach from cellulose fibers, suggesting that the agent may act, at least in part, by disrupting the glycocalyx necessary for adherence to, and rapid digestion of, cellulose.
Animals↗
Age and incubation time effects on in vitro caecal fermentation pattern in rabbits before and after weaning.
The caecal fermentation pattern was studied in four litters of rabbits. Rabbits were sequentially slaughtered at the age of 4 (before weaning), 6, 8 and 11 weeks. Their caecal contents were analyzed and incubated in vitro at 39 degrees C for 6 and 12 h. Net productions of short-chain fatty acids (SCFA), hydrogen and methane were determined. The average caecal weight increased three-times within two weeks after weaning, from 31.4 to 93.7 g. At the end of the experiment, the caecal weight was on average 134.4 g. A large variability of the SCFA concentration observed before weaning decreased after weaning. Measurements of caecal metabolite profiles and results of in vitro experiments indicated a certain decrease of propionate in favour of butyrate, associated with the weaning. The establishment of methanogens in rabbits was slow. Methanogenesis started in one out of four rabbits at the age of 6 weeks. Five weeks later, one of four rabbits still did not produce methane. The hydrogen recovery decreased between the 4th and the 6th week of age, due to the increase of the butyrate/propionate ratio. After the 6th week, the hydrogen recovery increased with age, apparently because of the increase in methane production. Hydrogen recovery tended to increase during incubation, suggesting a decrease of reductive acetogenesis. This increase was observed both in methanogenic and non-methanogenic rabbit caecal cultures. In former cultures, the ratio CH4/SCFA rose with time of incubation.
Aging↗
Effects of monensin, pyromellitic diimide and 2-bromoethanesulfonic acid on rumen fermentation in vitro.
The effects of monensin, 2-bromoethanesulfonic acid (2-BES) and pyromellitic diimide (diimide) on gas and volatile fatty acid (VFA) production by the rumen microbiota were compared in mixed culture. Oat hay, a hay-concentrate mixture (48% hay, 43% concentrate) and a soluble carbohydrate mixture were used as substrates for microbial growth. The highest concentrations of diimide (10 ppm) and 2-BES (30 microM) decreased methanogenesis by 97 and 76%, respectively, while H2 accumulation was increased 30- and 20-fold, respectively. The effect of monensin on methanogenesis was less dramatic as 10 ppm decreased CH4 accumulation 16% and H2 did not accumulate. Diimide and 2-BES decreased the acetate:propionate ratio with the hay (P less than .05) and soluble carbohydrate mixture (P less than .025). The numbers of saccharolytic, cellulolytic and methanogenic bacteria from sheep fed a diet with diimide (60 ppm) did not differ significantly from sheep fed a control diet. Semicontinuous culture incubations indicated that the mixed rumen microbial population could adapt and degrade diimide after 24 h of incubation.
Alkanesulfonates↗
Ruminal changes in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture.
Microbial and fermentation changes in the rumen in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture were studied using genetically bloat-susceptible, ruminally-cannulated adult cattle. Monensin at .66 and .99 mg/kg body weight daily reduced the severity of legume bloat by 41 and 73%, respectively. The same doses of lasalocid reduced bloat by 25 and 12%. Comparison of ruminal contents from animals before treatment with ruminal contents from antibiotic-treated animals showed no differences in pH, ammonia, soluble N, soluble carbohydrate, ethanol-precipitable slime and anaerobic bacterial counts. Monensin treatment decreased protozoal numbers and microbial activity, as evidenced by lower gas production from in vitro fermentation of ground alfalfa hay when compared to pretreatment. Lasalocid had no effect on protozoal counts and in vitro gas production. Addition of monensin or lasalocid (12 micrograms/ml) to in vitro fermentation of chopped, fresh alfalfa reduced microbial activity as evidenced by higher soluble N, lower ammonia concentration and decreased gas production. Monensin reduced the amount of ethanol-precipitable slime and protozoal numbers. Reduction in the severity of bloat when monensin was fed appears to be due to decreased protozoal numbers, which resulted in decreased gas production. Lasalocid did not reduce legume bloat because of its minimal effect on the ruminal protozoa.
Animal Feed↗
Chemical additives in rumen fermentations: in vitro effects of drugs, inoculum source and substrate of rumen volatile fatty acids and protozoa.
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Acetates↗
Chemical additives in rumen fermentations: in vitro effects of various drugs on rumen volatile fatty acids and protozoa.
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Acetates↗
Metabolizable energy of roughage in Taiwan.
The fixed metabolizable energy (ME) values from the NRC do not represent the true ME values of the various feedstuff used in livestock rations. Therefore, a rapid and effective method for evaluating the ME value of forage crops is required for proper ration formulation to improve production efficiency. Dairy goat digestion trials were conducted as the in vivo reference using the method of Menke and Steingass (1988) [Menke, K.H., Steingass, H., 1988. Feed Sci. Technol. 28, 91-97] which derived the amount of gas produced from in vitro fermentation. This method was adapted in this study to evaluate the ME value. In the goat digestion trial, six dairy goats were used for each roughage sample in a total fecal collection trial to determine the digestible nutrients, including energy (DE) and total digestible nutrient (TDN). The in vivo ME value was calculated using the method of Shiemann et al. (1971) [Shiemann, R., Nehring, K., Hoffmann, L., Jentsch, W., Chudy, A., 1971. Energetische Futterbewertung und Energienormen. VEB Deutscher Land-wirtschaftsverlag, Berlin, p. 75. (in German)] (ME(1) (MJ/kg)=5.2DCP+34.2DEE+12.8DCF+15.9DNFE, g/g). The in vitro ME value was then estimated from the chemical composition of the feed and amount of gas produced (G(b)) from in vitro fermentation. The value calculated from both with (ME(3)) and without (ME(2)) the inclusion of nitrogen free extracts (NFE) in the prediction equation. (ME(2) (MJ/kg)=0.145G(b)+4.12CP+6.5CP(2)+20.6EE+1.54, g/g; ME(3) (MJ/kg)=0.118G(b)+8.75CP+19.21EE+3.38NFE+0.691, g/g). The 12 roughage samples consisted different growth stages of Napier grass Taishi No. 2: (day of harvest; 40, 50, 60 and 65), dwarf Napier grass Taishi No. 1: (Day 40 and 65) and Pangola grass (Day 45) hay (Day 70), corn silage, imported alfalfa hay, timothy hay and Bermuda hay. The correlation between the ME values calculated from in vivo and in vitro without NFE was lower than with NFE inclusion in the equation. A higher correlation between the ME values calculated from in vivo and in vitro without NFE inclusion than with NFE inclusion in the prediction equation was obtained when alfalfa and corn silage were not included. This indicated that the ME value of forage could be estimated rapidly using this in vitro gas method adapted from Menke and Steingass (1988) [Menke, K.H., Steingass, H., 1988. Feed Sci. Technol. 28, 91-97] for practical applications in ration formulation.
Journal Article↗
The effect of nisin and monensin on ruminal fermentations In vitro.
When mixed ruminal bacteria and alfalfa were incubated in vitro, monensin and nisin both inhibited methane production so long as the concentrations were greater than 1 microM. Monensin- and nisin-dependent methane depressions caused a decrease in the acetate to propionate ratio (4.5 to 3.0). Total volatile fatty acid production was decreased by both monensin and nisin addition at concentrations greater than 2 microM. Starch-digesting ruminal bacteria were initially inhibited by monensin and nisin, but this effect disappeared after two to four transfers. Nisin always inhibited cellulolytic bacteria, but the nisin-dependent inhibition of cellulose digestion was no greater than the inhibition caused by monensin. Monensin and nisin also inhibited amino acid degradation, and nisin was more effective than monensin in controlling the growth of Clostridium aminophilum, an obligate amino acid-fermenting ruminal bacterium that can tolerate low concentrations of monensin. Because nisin was as potent as monensin, bacteriocins such as nisin may have potential as feed additives.
Acetates↗