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PubMed1993

Fermentation of dietary fibre by human colonic bacteria: disappearance of, short-chain fatty acid production from, and potential water-holding capacity of, various substrates.

Several dietary fibre-rich substrates were fermented in vitro with human colonic bacteria obtained from each of three adult male subjects to assess the extent of substrate fermentation short-chain fatty acid (SCFA) production, and the potential effect of fermented residues on faecal bulk. Substrates tested were two varieties of oat hull fibre, gum arabic, carboxymethylcellulose (CMC), soy fibre, psyllium, and six blends containing oat fibre, gum arabic, and CMC in various proportions. All substrates contained greater than 900 g/kg of total dietary fibre except for CMC (816 g) and soy fibre (778 g). In vitro organic matter disappearance during fermentation was greatest for gum arabic (69.5%), intermediate for soy fibre (56.4%), and less than 20% for the two oat fibres, CMC, and psyllium. Averaged across substrates, acetate, propionate, and butyrate were produced in the molar proportion of 64:24:12. Potential water-holding capacity (PWHC) of substrates, a measure of faecal bulking potential, was greatest for CMC (13.5 g H2O/g substrate) and lowest for gum arabic (1.92 g) and soy fibre (1.71 g). Organic matter disappearance and SCFA production of blends were directly proportional to their gum arabic content. Blend PWHC was proportional to CMC content. In vitro procedures are useful in predicting the actions of fibre blends formulated to produce desirable effects in vivo.

Adult↗
PubMed1995

Reducing cassava toxicity by heap-fermentation in Uganda.

Processing of cassava roots by the Alur tribe in Uganda includes a stage of solid substrate fermentation in heaps. Changes in cyanogen levels during the process, microflora involved, and protein levels, amino acid patterns and mycotoxin contamination of the final products were studied. Processing was monitored at six rural households and repeated at laboratory site, comparing it to sun-drying. Flour samples from rural households were analysed for residual cyanogens, mutagenicity, cytotoxicity and aflatoxins. Mean (+/- SD) total cyanogen levels in flours collected at rural households were 20.3 (+/- 16.8) mg CN equivalents kg-1 dry weight in 1990 (n = 23) and 65.7 (+/- 56.7) in 1992 (n = 21). Mean (+/- SD) levels of cyanohydrins plus HCN were 9.1 (+/- 8.7) in the 1992 flours. Total cyanogen levels in the village monitored batches were reduced considerably by heap-fermentation from 436.3 (+/- 140.7) to 20.4 (+/- 14.0) mg CN equivalents kg-1 dry weight cassava. Residual cyanogen levels were positively correlated with particle size of the resulting crumbs. Heap-fermentation was significantly more effective in reducing cyanogen levels than sun-drying alone, but did not always result in innocuous levels of of cyanogens. Dominant mycelial growth was from the fungi Neurospora sitophila, Geotrichum candidum and Rhizopus oryzae. No mutagenicity, cytotoxicity nor aflatoxins could be detected in the flours. Protein quantity and quality were not significantly reduced. Cassava gel viscosity pattern was modified to the consumers' preference by this method. As the removal of cyanogens was more efficient and we found no new obvious health risk, heap-fermentation can be regarded as an improvement compared to sun-drying alone in areas where cassava varieties with higher cyanogen levels prevail, but we recommend optimisation of the process for ensuring still safer products.

Dietary Proteins↗
PubMed1995

The effects of processing on the availability of lysine in kenkey, a Ghanaian fermented maize food.

The effects of processing steps such as soaking, fermentation, cooking and drying on the availability of lysine in kenkey were investigated. Soaking increased lysine availability by 21% and 22% for maize and maize-cowpea mixtures, respectively. Cooking of soaked samples further improved lysine availability by 68% and 31% for maize and maize-cowpea mixtures, respectively. Further significant improvements in lysine availability were effected by fermentation and cooking and values of 3.42 and 4.43 g/16 g N were recorded, respectively for maize and maize-cowpea doughs fermented for 4 days and cooked for 3 h. Cabinet drying had no significant effect on lysine availability, but drum drying of fermented maize and maize-cowpea doughs significantly lowered lysine availability in the resulting kenkey. A 1:1 mixture of cabinet and drum dried flours gave a product with higher available lysine content than the drum dried flour.

Biological Availability↗
PubMed1996

Nutritional quality of green beans (var. Tuf) fermented with starter culture.

Green beans (var. Tuf) were blanched at 90 degrees C for 20 min and then fermented in 3.08% salt solution with starter culture. Trypsin inhibitors, vitamins B1 and B2 and protein were determined before and during fermentation as well as after storage for 36 days. Trypsin inhibitors, vitamins B1 and B2 were reduced significantly (P < or = 0.05) during fermentation. A decrease in protein content was observed during the first 2 days of fermentation and thereafter the decrease was not significant (P > or = 0.05). Storage of pasteurised beans at 20 degrees for 36 days had no significant effect on the vitamins and protein.

Fabaceae↗
PubMed2000

Probiotic culture survival and implications in fermented frozen yogurt characteristics.

Low-fat ice cream mix was fermented with probiotic-supplemented and traditional starter culture systems and evaluated for culture survival, composition, and sensory characteristics of frozen product. Fermentations were stopped when the titratable acidity reached 0.15% greater than the initial titratable acidity (end point 1) or when the pH reached 5.6 (end point 2). Mix was frozen and stored for 11 wk at -20 degrees C. The traditional yogurt culture system contained the strains Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. The probiotic-supplemented system contained the traditional cultures as well as Bifidobacterium longum and Lactobacillus acidophilus. We compared recovery of Bifodobacterium by three methods, a repair-detection system with roll-tubes and plates on modified bifid glucose medium and plates with maltose + galactose reinforced clostridial medium. Culture bacteria in both systems did not decrease in the yogurt during frozen storage. The roll-tube method with modified bifid glucose agar and repair detection system provided at least one-half log10 cfu/ml higher recovery of B. longum compared with recoveries using modified bifid glucose agar or maltose + galactose reinforced clostridial agar on petri plates. No change in concentrations of lactose or protein for products fermented with either culture system occurred during storage. Acid flavor was more intense when product was fermented to pH 5.6, but yogurt flavor was not intensified. The presence of probiotic bacteria in the supplemented system seemed to cause no differences in protein and lactose concentration and sensory characteristics.

Bifidobacterium↗
PubMed2000

Transit of radical scavenging activity of milk products prepared by Maillard reaction and Lactobacillus casei strain Shirota fermentation through the hamster intestine.

Oxidative stress in the colon is associated with the incidence of colon cancer. In situ, the suppression of oxidative stress in the colon would be an effective form of prevention of the cancer. In this study we investigated the transit of the radical scavenging activity of milk products through the hamster intestinal tract. Two types of skim milk products were prepared by Maillard reaction and then lactic acid fermentation. Heat treatment enhanced the radical scavenging activity for 2,2-diphenyl-1-picrylhydrazyl radical of skim milk. The activity was further increased by fermentation with Lactobacillus casei strain Shirota. Normal hamsters were fed these milk products for 14 d. For potential radical scavenging activity per unit dry weight of feces and cecal content, the groups ranked in the order of fermented product-fed hamsters > heated product-fed hamsters > control hamsters, reflecting the order of the potential of the corresponding diets. Approximately 12% of the activity of the heated and the fermented product diets passed through the gastrointestinal tract. These results suggest that some of the radical scavenging activity generated by food processing reached the colon in nonabsorbable products.

Animals↗
PubMed2002

Influence of a Spirulina platensis biomass on the microflora of fermented ABT milks during storage (R1).

The objective of this research was to investigate the effect of a cyanobacterial (Spirulina platensis) biomass on the microflora of a probiotic fermented dairy product during storage at two temperatures. Spirulina-enriched and control (plain) fermented acidophilus-bifidus-thermophilus (ABT) milks were produced using a fast fermentation starter culture (ABT-4) as the source of Lactobacillus acidophilus (A), bifidobacteria (B), and Streptococcus thermophilus (T). Incubation took 6 h at 40 degrees C. As for the cyanobacterial product, the S. platensis biomass was added to the process milk during stirring at pH 4.5 to 4.6. Thereafter, the ABT-type fermented milks were cooled to 25 degrees C in ice water, filled into sterile, tightly capped centrifuge tubes, further cooled at 4 degrees C for 24 h, and then stored either at 15 degrees C for 18 d or at 4 degrees C for 42 d. Microbiological analyses and acidity measurements were performed at regular intervals. Our results showed that the counts of the starter organisms were satisfactory during the entire storage period at both temperatures applied in this research. The S. platensis biomass had a beneficial effect on the survival of ABT starter bacteria regardless of storage temperature. Postacidification was observed at 15 degrees C, whereas pH remained stable during refrigerated storage at 4 degrees C. The abundance of bioactive substances in S. platensis is of great importance from a nutritional point of view because thus the cyanobacterial biomass provides a new opportunity for the manufacture of functional dairy foods.

Animals↗
PubMed2002

Microbial community dynamics during the Scamorza Altamurana cheese natural fermentation.

The growth dynamics of the natural microbial community responsible for the fermentation of Scamorza Altamurana, a typical Southern Italian cheese made using backslopping, was investigated applying a polyphasic approach combining 1) microbial enumeration with culture media, 2) randomly amplified polymorphic DNA (RAPD) fingerprinting of microbial communities, 3) sequencing of partial 16S ribosomal DNA (rDNA) genes, and 4) physiological tests. Viable cell counts on different culture media showed that the cocci community prevailed during the 18 h of curd fermentation and the 6 d of cheese ripening. RAPD fingerprinting made it possible to isolate 25 different strains identified by 16S rDNA sequencing as belonging to five species of Lactobacillus, three species of Streptococcus, one species of Weissella, and one species of Enterococcus. The physiological analyses of all lactic acid bacteria strains revealed that the isolates belonging to Streptococcus genus were the most acidifying, whereas lactobacilli were most proteolytic. Streptococcus thermophilus C48W and Lactobacillus delbrueckii subsp. bulgaricus B15Z dominated all through the fermentation process. Furthermore, they seemed to be stable in a subsequent whey sample analyzed after 7 mo. The recovery of strains endowed with interesting technological features, such as acidifying and proteolytic activities, and surviving in natural whey could allow the upscaling of cheese processing safeguarding the organoleptic characteristics of Scamorza Altamurana and could possibly improve other fermented dairy products.

Animals↗
PubMed2003

Corn silage management: effects of hybrid, maturity, inoculation, and mechanical processing on fermentation characteristics.

Two experiments were conducted to evaluate the effects of hybrid, maturity, mechanical processing, and inoculation of corn silage on fermentation characteristics. In experiment 1, Pioneer hybrid 3845 corn silage was harvested at three maturities (hard dough, one-third milkline, two-thirds milkline). In experiment 2, Pioneer hybrids 3845 and Quanta were harvested at three maturities (one-third milkline, two-thirds milkline, and blackline). In both experiments, corn silage was harvested at each maturity with and without mechanical processing and with and without inoculation. In experiments 1 and 2, corn silage was harvested at a theoretical length-of-cut of 6.4 and 12.7 mm, respectively. Maturity at harvest tended to have a greater impact on silage fermentation characteristics of corn silage than mechanical processing and inoculation. In experiments 1 and 2, corn silage harvested at the earliest maturity tended to have decreased dry matter content and increased water-soluble carbohydrate concentrations during the ensiling process than corn silage harvested at advanced maturities. In experiment 2, pH levels were lower for corn silage harvested at the early maturity (one-third milkline) compared with advanced maturities (two-thirds milkline and blackline) by 57 d after ensiling. The difference in pH can be explained by the greater concentration of water-soluble carbohydrates at the early maturity (one-third ML) soon after ensiling (2, 3, 6 and 10 d after ensiling) compared with advanced maturities (two-thirds ML and BL). The increased water-soluble carbohydrate concentrations in the less mature corn silage provided nutrients for bacteria to grow and produce primarily lactic acid (6, 10, and 57 d after ensiling) and some acetic acid (2, 3, 6, and 10 d after ensiling) which reduced the pH of corn silage more than at the advanced maturities. There was a slight change in silage fermentation characteristics when corn silage was inoculated with Pioneer 1132 inoculant in experiment 1. The inoculated corn silage had increased temperature, lactate and acetate concentrations, and lower water-soluble carbohydrate and pH levels compared with uninoculated corn silage. Dry matter recovery tended to be greater for processed corn silage in experiment 1, and greater for unprocessed corn silage in experiment 2. It appears that when fermentation was greater (increased temperature and lactate concentration 57 d after ensiling) the dry matter recovery was lower.

Acetic Acid↗
PubMed2003

Effects of casein and glucose on responses of cows fed diets based on restrictively fermented grass silage.

This study was conducted to investigate whether well fed dairy cows given restrictively fermented grass silage diet will respond to incremental glucose and amino acid supply at early stage of lactation. Four rumen-cannulated Finnish Ayrshire cows were used in a 4 x 4 Latin square experiment with 14-d periods. The cows were fed good quality restrictively fermented grass silage ensiled with a formic acid additive for ad libitum intake. A concentrate mixture consisting of barley (85%) and solvent extracted rapeseed meal (11.4%) was given at a rate of 9 kg/d. The four treatments were continuous abomasal infusions of water (control), casein 300 g/d, glucose 300 g/d, and casein 300 g/d + glucose 300 g/d. The infusions had only minor effects on feed intake, diet digestibility, or rumen fermentation pattern. Both casein and glucose infusions increased milk, protein and lactose yields the effects being partly additive on the combined infusion. Infused casein increased milk protein and urea as well as plasma urea concentrations. Both casein and glucose tended to increase plasma glucose concentration. Casein increased arterial plasma concentrations of essential amino acids (EAA), branched-chain AA (BCAA), and total AA (TAA). Both casein and glucose, although glucose usually less than casein, increased arteriovenous differences of EAA, nonessential AA, BCAA, and TAA. Extraction efficiencies of AA were higher for glucose than for casein. Mammary plasma flow was at highest on the control diet, but reduced owing to infused nutrients, the reduction being less with combined rather than separate infusions of casein and glucose. Based on the partly additive increases in milk production parameters and changes in plasma metabolites, it is suggested that glucose alone increased milk protein yield by sparing AA from hepatic utilization, while casein increased both supply of AA and glucose. It was concluded that cows at early stage of lactation fed diets comprising of restrictively fermented grass silage and a cereal-based concentrate suffer from both limited AA and glucose supplies.

Abomasum↗
PubMed2004

The effects of buffered propionic acid-based additives alone or combined with microbial inoculation on the fermentation of high moisture corn and whole-crop barley.

Buffered propionic acid-based additives (BP) alone or in combination with a microbial inoculant containing lactic acid bacteria (MI) were mixed with ground, high moisture corn or whole-crop barley and ensiled in triplicate laboratory silos to investigate their effects on silage fermentation and aerobic stability. The inoculant and chemicals were applied separately for treatments that included both additives. The addition of MI alone had no effect on DM recovery, fermentation end products, or aerobic stability of high moisture corn. However, treatments with 0.1 and 0.2% BP (alone and the combination) had more than 10- and 100-fold fewer yeasts, respectively, and they also had greater concentrations of propionic acid than did untreated corn. Corn treated with only 0.1 (161 h) and 0.2% (218 h) BP tended to be more stable when exposed to air than untreated corn (122 h). Treatment with MI + 0.2% BP markedly improved the aerobic stability (>400 h) of high moisture corn. With whole-crop barley, the addition of MI alone, BP alone, and combinations of MI and BP prevented the production of butyric acid that was found in untreated silage (0.48%). All barley silages that had MI in their treatments underwent a more efficient fermentation than treatments without MI, as evident by a greater ratio of lactic:acetic acid and more DM recovery than in untreated silage. Increasing levels (0.1 to 0.2%) of BP added together with MI improved the aerobic stability of barley (190 and 429 h) over the addition of MI alone (50 h). These data show that buffered propionic acid-based products are compatible with microbial inoculants and, in some circumstances when used together, they can improve the fermentation and aerobic stability of silages.

Acetic Acid↗
PubMed1992

Effect of direct-fed microbials on rumen microbial fermentation.

Nonbacterial, direct-fed microbials added to ruminant diets generally consist of Aspergillus oryzae fermentation extract, or Saccharomyces cerevisiae cultures, or both. Results from in vivo research have been variable regarding effects of direct-fed microbials on ruminant feedstuff utilization and performance. Some research has shown increased weight gains, milk production, and total tract digestibility of feed components, but others have shown little influence of direct-fed microbials on these parameters. In vitro research with mixed ruminal microorganisms likewise has been inconsistent regarding the effects of direct-fed microbials. Several researchers observed that direct-fed microbials increased cellulolytic bacterial numbers in the rumen and stimulated the production of some fermentation end products. This suggests that direct-fed microbials may be providing growth factors for the ruminal microbes. However, other researchers have reported no effect of direct-fed microbials on in vitro fiber digestion. Recent research demonstrated that growth of the predominant ruminal bacterium Selenomonas ruminantium in lactate medium as well as lactate uptake by whole cells of Sel. ruminantium were markedly increased by an A. oryzae fermentation extract and an S. cerevisiae culture. In addition, both products increased the production of acetate, propionate, succinate, total VFA, and cell yield (grams of cells per mole of lactate). Therefore, it appears that these direct-fed microbials provide soluble factors that stimulate lactate utilization by Sel. ruminantium. Evidence is presented indicating that the malate content of the A. oryzae fermentation extract and S. cerevisiae culture may be involved in this stimulation.

Animals↗
PubMed1994

Antimutagenicity of fermented milk.

Reconstituted nonfat dry milk was fermented by Lactobacillus helveticus CH65, Lactobacillus acidophilus BG2FO4, Streptococcus salivarius ssp. thermophilus CH3, Lactobacillus delbrueckii ssp. bulgaricus 191R, and by a mixture of the latter two organisms. The fermented milks were then freeze-dried, extracted in acetone, dissolved in dimethylsulfoxide, and assayed for antimutagenicity in the Ames test (Salmonella typhimurium TA 100) against N-methyl, N'-nitro, N-nitroso-guanidine, and 3,2'-dimethyl-4-amino-biphenyl. Dose-dependent activity was significant against both mutagens in all extracts. Maximal inhibitory activity against 3,2'-dimethyl-4-aminobiphenyl and N-methyl, N'-nitro, N-nitroso-guanidine was 2- and 2.7-fold greater, respectively, than that exhibited by extracts of unfermented milk. Extracts of milk fermented by L. delbrueckii ssp. bulgaricus 191R were examined further. Compounds that were responsible for activity against both mutagens were less soluble in aqueous solutions than in dimethylsulfoxide. Adjustment of milk fermented by L. delbrueckii ssp. bulgaricus 191R to pH 3, 7.6, or 13 prior to freeze-drying and acetone extraction did not significantly alter the activity specific for 3,2'-dimethyl-4-aminobiphenyl. In contrast, compounds with activity specific for N-methyl, N'-nitro, N-nitrosoguanidine were less extractable at pH 7.6. The weak antimutagenicity of unfermented milk was not increased by addition of 2% L-lactic acid.

Aminobiphenyl Compounds↗
PubMed1996

Modulation of proliferation, second messenger levels, and morphotype expression of the rat intestinal epithelial cell line IEC-6 by fermented milk.

Trophic effects of milk fermented with Lactobacillus helveticus, Lactobacillus paracasei ssp. paracasei, Bifidobacterium sp., or the combination of Lactobacillus bulgaricus and Streptococcus thermophilus (yogurt) were studied on the IEC-6 intestinal epithelial cell line. Incorporation of [methyl-3H]thymidine, mitochondrial dehydrogenase activities, cyclic AMP production, and differentiation of levels of the IEC-6 strain were evaluated between the 15th and 30th passage in culture. All fermented and unfermented milks enhanced trophic responses of IEC-6 cells in a dose-dependent manner. Compared with the corresponding milks, supernatant fractions were more effective in stimulating mitochondrial dehydrogenase response. Fermented milk supernatants were also more effective than the corresponding unfermented fractions. Increases in DNA synthesis and cyclic AMP confirmed the activation observed with mitochondrial dehydrogenase. Yogurt induced the more trophic response with an increased number of the more differentiated cell morphotype. Fermentation with L. casei also demonstrated an important trophic adaptation of IEC-6 cells. Milk processing by lactic acid bacteria enhanced trophic and proliferation responses of intestinal epithelial cell line IEC-6. These results suggested that IEC-6 cells could represent an accurate and easy in vitro model for testing the trophic quality of various nutrients and for an optimization of physiological digestive functions.

Animals↗
PubMed1996

The effect of milk fermentation by Lactobacillus helveticus on the release of peptides during in vitro digestion.

This study evaluated the effect of protein hydrolysis by lactic acid bacteria during milk fermentation on the release of amino acids and peptides duing subsequently simulated peptic and pancreatic digestion. After digestion with trypsin, we compared the elution patterns of proteins and peptides obtained from unfermented milk and from milk fermented by Lactobacillus helveticus under pH control, using HPLC gel filtration and reverse-phase HPLC. The results indicate that milk fermentation affects the release of some amino acids during simulated gastrointestinal digestion and has a major impact on the modification of protein elution profiles obtained after digestion with trypsin. We conclude that proteolysis during fermentation may lead to the formation of novel peptides during gastrointestinal digestion.

Amino Acids↗
PubMed1997

The endogenous polysaccharide utilization rate of mixed ruminal bacteria and the effect of energy starvation on ruminal fermentation rates.

When mixed ruminal bacteria were starved in vitro for 24 h, cellular ATP decreased, but there was little change in cell protein. Starved ruminal bacteria derived most of their ATP from cellular polysaccharide. Because polysaccharide declined at a first-order rate of 23%/h, it was possible to estimate the endogenous polysaccharide utilization rate at various stages of starvation by multiplying the amount of utilizable polysaccharide remaining at each time point by 0.23. The bacteria initially had a rate of soluble carbohydrate fermentation that was > 717 micrograms of hexose equivalent/mg of protein per h. Starvation had little impact on the rate of soluble carbohydrate fermentation until 8 to 12 h, and the endogenous polysaccharide utilization rate was < 10 micrograms of hexose/mg of protein per h. The bacteria digested ball-milled cellulose at a rate of 24 micrograms of hexose/mg of protein per h for 8 to 12 h. Even bacteria that had been starved for 24 h fermented cellulose at a rate of 16 micrograms of hexose/mg of protein per h. The rate of methane production was initially 70 nmol of methane/mg of protein per min. Short periods of starvation (< 12 h) had little impact on methane production, but longer times caused an almost complete inhibition of methanogenesis. The rate of amino acid deamination was initially 31 nmol of ammonia/mg of protein per min, and the critical phase of starvation was again 8 to 12 h. Ruminal bacteria that were harvested at 24 h after feeding had 10-fold less polysaccharide than did bacteria that were harvested at 2 h after feeding, but this polysaccharide supported high rates of soluble carbohydrate and cellulose fermentation, deamination, and methane production.

Adenosine Triphosphate↗
PubMed1998

Cell-free whey from milk fermented with Bifidobacterium breve C50 used to modify the colonic microflora of healthy subjects.

The ingestion of viable bacteria is thought to be required to modify intestinal microflora. In the present study, the effects on fecal flora of consumption of cell-free concentrated whey from milk that had been fermented with Bifidobacterium breve C50 was tested using 10 healthy human volunteers. Results were compared with effects of a commercial milk formula that had been fermented with Streptococcus thermophilus and B. breve C50 and given to 10 control subjects. Nitroreductase and beta-glucuronidase activities were assessed as risk indexes for colon carcinogenesis, and beta-galactosidase was measured as an indicator of the fermentation capacity of the colonic flora. Fecal excretion of Bacteroides fragilis, Clostridium perfringens, and clostridial spores decreased after 7 d of consumption of either preparation; however, counts of bifidobacteria only increased after intake of B. breve whey. Fecal pH was reduced from 7.1 +/- 0.2 to 6.6 +/- 0.3 after intake of whey that had been fermented with Bif. breve. Fecal nitroreductase and beta-glucuronidase significantly decreased, and beta-galactosidase activity increased, after consumption of either preparation. The results indicate that ingestion of viable bifidobacteria was not required to modify intestinal flora of humans. Repression of B. fragilis and clostridia seems to be independent of colonic bifidobacterial overgrowth in humans.

Adult↗
PubMed1998

Inhibition of sulfate reduction to sulfide by 9,10-anthraquinone in in vitro ruminal fermentations.

We studied the effects of sulfur and 9,10-anthraquinone on in vitro ruminal fermentation and production of hydrogen sulfide. A complete, pelleted diet containing 26.8% acid detergent fiber, 15.9% crude protein, and 0.25 to 0.29% sulfur was used as the basal substrate. Fermentations were conducted using the basal substrate and various sulfur additions (elemental sulfur, thiosulfate, calcium sulfate, and sodium sulfate) with or without varying amounts of 9,10-anthraquinone. An increase in the sulfur content of the substrate to > 1.0% with various sources of sulfur had minimal effects on concentrations of volatile fatty acids, but the production of hydrogen sulfide increased. High amounts of 9,10-anthraquinone (10 and 25 ppm of fluid) decreased the molar proportion of acetate and decreased the production of methane and hydrogen sulfide. However, 9,10-anthraquinone increased the molar proportions of propionate and butyrate. Approximately 70% of 9,10-anthraquinone was recovered after 24 h of in vitro ruminal fermentation. These findings suggest that 9,10-anthraquinone has the potential to reduce the production of methane and hydrogen sulfide in ruminal fermentations.

Ammonia↗