Fermentation in the Rumen of the Sheep

1951 ◽  
Vol 28 (1) ◽  
pp. 74-82
Author(s):  
F. V. GRAY ◽  
A. F. PILGRIM ◽  
R. A. WELLER

1. When wheaten hay and lucerne hay were fermented by organisms from the rumen of the sheep it was necessary to employ a large inoculum of rumen fluid in order to reproduce the rumen fermentation in vitro. With a small inoculum the fermentation did not conform to the known characteristics of the natural process. 2. Products per kilogram of wheaten hay fermented in vitro were: fatty acids 200-250 g.--acetic acid 41%, propionic acid 43% and butyric acid 16% (by weight); methane 15 l. Products per kilogram of lucerne hay were: fatty acids 250-300 g.--acetic acid 53%, propionic acid 29% and butyric acid 18% (by weight); methane 20 l. 3. The findings support the view that, owing to the more rapid absorption of propionic than of the other acids from the rumen, the proportion of this acid remaining in the rumen fluid is considerably less than the proportion actually formed in the fermentation.

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 108
Author(s):  
Yichong Wang ◽  
Sijiong Yu ◽  
Yang Li ◽  
Shuang Zhang ◽  
Xiaolong Qi ◽  
...  

Nutritional strategies can be employed to mitigate greenhouse emissions from ruminants. This article investigates the effects of polyphenols extracted from the involucres of Castanea mollissima Blume (PICB) on in vitro rumen fermentation. Three healthy Angus bulls (350 ± 50 kg), with permanent rumen fistula, were used as the donors of rumen fluids. A basic diet was supplemented with five doses of PICB (0%–0.5% dry matter (DM)), replicated thrice for each dose. Volatile fatty acids (VFAs), ammonia nitrogen concentration (NH3-N), and methane (CH4) yield were measured after 24 h of in vitro fermentation, and gas production was monitored for 96 h. The trial was carried out over three runs. The results showed that the addition of PICB significantly reduced NH3-N (p < 0.05) compared to control. The 0.1%–0.4% PICB significantly decreased acetic acid content (p < 0.05). Addition of 0.2% and 0.3% PICB significantly increased the propionic acid content (p < 0.05) and reduced the acetic acid/propionic acid ratio, CH4 content, and yield (p < 0.05). A highly significant quadratic response was shown, with increasing PICB levels for all the parameters abovementioned (p < 0.01). The increases in PICB concentration resulted in a highly significant linear and quadratic response by 96-h dynamic fermentation parameters (p < 0.01). Our results indicate that 0.2% PICB had the best effect on in-vitro rumen fermentation efficiency and reduced greenhouse gas production.


1982 ◽  
Vol 54 (2) ◽  
pp. 127-135
Author(s):  
Liisa Syrjälä-Qvist

The criteria used in comparing the utilization of grass silage by reindeer and sheep were rumen pH, ammonia, volatile fatty acids (VFA) and microbes. Rumen samples were taken before feeding, and 2 ½ and 5 ½ hours after the beginning of feeding. Rumen fermentation was lower in the reindeer than in the sheep and differed less between the three sampling times. In the reindeer/the pH of the rumen fluid averaged 6.94 and in the sheep 6.61. The average amounts of NH3—N were 17.0 and 24.2 mg/100 ml rumen fluid and those of total VFA 8.46 and 10.90 mmoles/100ml rumen fluid, respectively. The proportion of acetic acid in the VFA in the reindeer was 75.3 molar % and in the sheep 66.0 molar %, the corresponding values for propionic acid being 18.5 and 22.0 molar % and for butytic acid 4.2 and 8.8 molar %. The number of rumen ciliates in the reindeer averaged 87/mm3 rumen contents and in the sheep 314/ mm3. The numbers of bacteria were 16.0 X 106/mm3, respectively. The proportion of the total microbe mass in the reindeer rumen contents was 1.8 % and in the sheep 2.4 %. The proportions of bacteria in this mass were 87 % and 70 %, respectively. The differences between the reindeer and sheep in the rumen fermentation results and in the numbers of rumen microbiota were nearly all statistically significant (P


1952 ◽  
Vol 29 (1) ◽  
pp. 57-65 ◽  
Author(s):  
F. V. GRAY ◽  
A. F. PILGRIM ◽  
H. J. RODDA ◽  
R. A. WELLER

1. The mixture of volatile fatty acids in the rumen of the sheep has been shown to include formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid, another valeric acid isomer, caproic acid and an acid which is probably heptoic acid. The proportions in which they are present have been determined. 2. When acetic acid labelled with 14C in the carboxyl group was incorporated in the rumen fermentation in vitro, active carbon appeared later in all the higher acids. When labelled propionic acid was included in the fermentation, active carbon appeared in the valeric but not in the butyric acid. The results suggest a synthesis of the higher acids by condensation of the lower ones with 2-C compound in equilibrium with acetic acid. The extent of such syntheses and other possible modes of origin of the fatty acids are discussed.


1968 ◽  
Vol 19 (5) ◽  
pp. 791 ◽  
Author(s):  
GJ Faichney

Experiments are reported in which sheep were given roughage diets or a high concentrate diet and the VFA absorbed from the rumen were estimated by an in vitro fermentation procedure. The VFA absorbed were compared with the digestible and metabolizable energy intakes of the sheep, determined in digestibility trials, for each diet. For a lucerne diet, a straw diet, and the high concentrate diet the proportions of the digested energy absorbed as VFA were 33.6, 42.4, and 33.2% respectively. On the lucerne diet, the difference between the mean molar proportions of the VFA absorbed and the mean molar proportions of the VFA in the rumen approached significance for acetic acid (P < 0.10) and was highly significant for butyric acid (P < 0.01). The differences were not significant for the other diets.


1951 ◽  
Vol 28 (1) ◽  
pp. 83-90
Author(s):  
F. V. GRAY ◽  
A. F. PILGRIM

1. Analyses of the rumen fluid of sheep fed on wheaten hay and on lucerne hay showed that characteristic changes take place in the composition of the mixture of volatile fatty acids in the rumen throughout the day. 2. The changes conform closely to those predicted from the composition of the mixture of fatty acids produced from the same two fodders in vitro. They support the view that propionic acid is relatively more rapidly absorbed than either acetic or butyric acid, and that the fermentation of these fodders in the rumen produces a mixture of the acids in which propionic acid forms a larger proportion than it does in the rumen fluid.


1969 ◽  
Vol 23 (3) ◽  
pp. 567-583 ◽  
Author(s):  
J. D. Sutton

1. Studies were made of the fermentation of D-glucose, D-fructose, D-galactose, D-xylose, L-arabinose and sucrose by rumen contents from two cows fed 1 kg hay and 4 or 5 kg flaked maize once daily. The proportions of volatile fatty acids (VFA) in the rumen before addition of carbohydrates varied widely but on average acetic acid constituted about 52%, propionic acid about 29% and n-butyric acid about 13% of the total.2. In in vitro experiments, 896 mg of the monosaccharides and 851 mg sucrose were added to 150 g mixed rumen contents incubated for 2 h; the carbohydrates were added at 10 min intervals throughout the incubation on three occasions with each cow. Mean proportions of the carbohydrates fermented ranged from about 60% of the pentoses to about 85% of sucrose and glucose. Of the VFA produced from galactose and the pentoses, acetic acid constituted about 40%, propionic acid 45–55% and n-butyric acid 1–7%; very little n-valeric acid was produced. With the other carbohydrates results from the two cows differed, owing mainly to the production of appreciable amounts of n-valeric acid with one cow only. Acetic acid constituted about 40% of the VFA produced from fructose and sucrose, propionic acid 20–40%, n-butyric acid 14–22% and n-valeric acid up to 12%. The proportions of VFA produced from glucose were intermediate between the other two groups.3. Net recovery of carbon from fermented carbohydrate in VFA was about 35–45%. A further 1–6%, of fermented glucose, fructose and sucrose was recovered in lactic acid.4. In in vivo experiments, the monosaccharides only were infused into the rumen for 8 h at the rate of 200 g/h. Changes in the concentrations of substrates and products varied widely, owing to the variable basal fermentation, but changes in the proportions of VFA in the rumen were similar to those found in vitro.5. The results of the in vitro experiments were compared with those obtained in earlier experiments in which the same cows were given a diet containing 70% hay. Significant regressions (P < 0.05) were found between the molar proportions of acetic, propionic and n-valeric acids produced from the substrates and the proportions of these acids present in the rumen contents at the start of the incubations, but the relationships differed markedly among the different carbohydrates. Most of the significant regressions were positive but negative regressions for propionic acid production from fructose and sucrose with one cow suggested the existence of more complex interrelationships among two or more VFA.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruiling Gao ◽  
Zifu Li ◽  
Xiaoqin Zhou ◽  
Wenjun Bao ◽  
Shikun Cheng ◽  
...  

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.


2014 ◽  
Vol 59 (No. 10) ◽  
pp. 450-459 ◽  
Author(s):  
M. Gunal ◽  
A. Ishlak ◽  
A.A. AbuGhazaleh ◽  
W. Khattab

The effects of adding essential oils (EO) at different levels (125, 250, 500 mg/l) on rumen fermentation and biohydrogenation were examined in a rumen batch culture study. Treatments were: control without EO (CON), control with anise oil (ANO), cedar wood oil (CWO), cinnamon oil (CNO), eucalyptus oil (EUO), and tea tree oil (TEO). Essential oils, each dissolved in 1 ml of ethanol, were added to the culture flask containing 40 ml of buffer solution, 2 ml of reduction solution, 10 ml of rumen fluid, 25 mg of soybean oil, and 0.5 g of the diet. After 24 h of incubation in a water batch at 39&deg;C, three samples were collected from each flask and analyzed for ammonia-N, volatile fatty acids (VFA), and fatty acids (FA). Expect for CNO, the proportions of acetate, propionate, and acetate to propionate ratios were not affected (P &gt; 0.05) by EO addition. Addition of CWO, CNO, and TEO reduced total VFA concentrations (P &lt; 0.05) regardless of dose level. The ammonia-N concentration was greater in cultures incubated with EO regardless of dose level. Compared with the CON, the concentrations of C18:0 and trans C18:1 were reduced (P &lt; 0.05) with EO addition regardless of dose level. Compared with the CON, the concentration of linoleic acid was greater (P &lt; 0.05) when EO were added at 500&nbsp;mg/l. EO tested in this study had no effects on VFA profile but significantly reduced the formation of biohydrogenation products (C18:0 and trans C18:1).


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Fang ◽  
Sinmin Ji ◽  
Dingwu Huang ◽  
Zhouyue Huang ◽  
Zilong Huang ◽  
...  

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.


1967 ◽  
Vol 47 (1) ◽  
pp. 31-38 ◽  
Author(s):  
R. A. Clarke ◽  
W. K. Roberts

Two metabolism experiments were conducted with rumen-fistulated sheep to study effects of increasing dietary levels of unsaturated fatty acids upon ration digestibility and rumen-fluid volatile fatty acids. Apparent digestibility of ration components was not significantly (P > 0.05) affected by diet. However, crude fat digestibility values, which include fecal soap excretion, were 11–19 digestion units lower than comparable ether extract values. When diets high in unsaturated fatty acids were fed, the rumen and fecal levels of these acids were lower than dietary levels, suggesting that hydrogenation of C-18 polyethnoid fatty acids was occurring. Fecal soap excretion was affected very little by dietary unsaturated fatty acids, but stearic acid proportion of fecal soaps increased as the level of dietary unsaturated fatty acids increased. The ratios of acetic to propionic acid gradually decreased as the unsaturated fatty acids of the ration increased in one experiment, but in the other experiment no consistent pattern was observed.


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