Nutritional status and intake regulation in sheep. V. Effects of intraruminal infusions of volatile fatty acids upon voluntary intake of roughage by sheep

1966 ◽  
Vol 17 (5) ◽  
pp. 741 ◽  
Author(s):  
AR Egan

Results of experiments with infusions of volatile fatty acids into the rumen reveal that the induced changes in voluntary intake of roughages are not immediate, and vary in extent between animals. Single infusions resulted in subsequent depressions of feed intake, these being only partly related to the amount of energy of the infused volatile fatty acids. When longer-term infusions were made, acetic acid in small quantities depressed feed intake more than did propionic, and propionic acid modified the effect of acetic when the two were given together. Also recorded is an observation that animals receiving a casein-supplemented roughage diet reduced their feed intake when casein was infused per duodenum over 14-day periods. Results are discussed in relation to an hypothesis of an indirect mechanism attempting to maintain or restore the original energy balance, but showing considerable delay or inertia and imprecision when observed on a day to day basis.

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.


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.


1957 ◽  
Vol 49 (2) ◽  
pp. 171-179 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.


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.


2009 ◽  
Vol 60 (2) ◽  
pp. 339-346 ◽  
Author(s):  
H. Fabian Jacobi ◽  
Christian R. Moschner ◽  
Eberhard Hartung

Recently biogas production from agricultural sources has rapidly developed. Therefore the demands on biogas plants to optimise the efficiency of the anaerobic digestion (AD) process have grown immensely. At present there is no online-supervision tool available to monitor the AD process, but costly and time-consuming chemical analyses are necessary. The possibility to use near-infrared spectroscopy (NIRS) in order to track relevant process parameters like total volatile fatty acids (VFA), acetic acid and propionic acid was investigated in the present research project. A NIR-sensor was integrated into a full-scale 1 MW biogas plant and NIR-spectra of the fermenter contents were recorded semi-continuously for 500 days. Weekly samples were taken and analysed for the above mentioned parameters. Calibration models were calculated, capable of following these parameters: VFA (r2=0.94), acetic acid (r2=0.69), propionic acid (r2=0.89).


1988 ◽  
Vol 39 (3) ◽  
pp. 505 ◽  
Author(s):  
HA Abdul-Razzaq ◽  
R Bickerstaffe ◽  
GP Savage

Changes in the body composition, blood metabolites and rumen volatile fatty acids were measured in growing 12-week-old lambs fed whole-loose barley or ground barley pelleted with minerals for 10 weeks. Feeding whole-loose barley produced a propionic type of rumen fermentation and ground barley pelleted with minerals, an acetic acid type.The propionic type of fermentation was associated with a significant increase in the plasma concentrations of glucose and insulin, a reduction in the concentrations of plasma urea, and a reduction in almost all of the plasma amino acids, particularly alanine, methionine, valine, isoleucine and leucine. There was also a significant increase in the amount of body fat and dry matter, a higher level of protein per kg fat free empty body weight, and a more efficient utilization of dietary energy in the animals with a propionic acid type of fermentation.The elevation in the concentration of rumen propionic acid produced two important changes. It increased the supply of the main glucogenic precursor propionate, which probably reduces the body's requirement for alternative gluconeogenic precursors, and it stimulated directly and/or indirectly the pancreatic secretion of insulin. The latter is most likely responsible for the efficient peripheral utilization of glucose and other nutrients in lambs with a propionic acid type of rumen fermentation.Thus, a propionic type of fermentation is associated with an increase in the plasma levels of glucose and insulin, an increase in fat deposition and an increase in the efficiency of ME retention; all of these factors contribute to the improved performance of this group of lambs compared to those with an acetic acid type of fermentation.


2014 ◽  
Vol 955-959 ◽  
pp. 527-531
Author(s):  
Jian Zheng Li ◽  
Yu Peng Zhang ◽  
Chong Liu ◽  
Ze Yu Tang

The activities of methanogen are easily affected by inhibitory substances and lead to anaerobic digestion failure. To investigate inhibitory effects on methanogenesis of a methanogen-enriched sludge, pH, volatile fatty acids (such as acetic acid, propionic acid and butyric acid), and ammonia were used as inhibitory factors and a L16(45) orthogonal table was employed to design batch experiments. The result of variance analyses shows that pH has the greatest impact on the methanogenesis of the enriched culture. The impact of butyrate, NH3, acetate and propionate was decreased in order. DGGE finger-print shows that there was only one methanogen in the inoculum sludge.


2001 ◽  
Vol 44 (10) ◽  
pp. 129-135 ◽  
Author(s):  
A. Shanableh ◽  
S. Jones

The production of useful organic matter from sludge expands the potential for utilizing the product as a resource. This paper is focused on the accumulation and removal of volatile fatty acids (VFAs) produced from primary, secondary and a mixture of both sludges using hydrothermal treatment with and without the use of oxidants. The results confirmed that the maximum accumulation of VFAs was achieved at moderate hydrothermal treatment temperatures below 200°C, and was dependent on the composition of sludge and the amount of oxidant used for treatment. The maximum accumulation reached 0.26-0.36 mg VFAs as COD per mg VS from the three sludge types. Acetic acid dominated the VFAs and was followed by propionic acid, with the other VFAs accounting for less than 5% of the total VFAs. As hydrothermal treatment progressed in terms of COD removal, the contribution of acetic acid to the total VFAs increased while the contributions of the other VFAs decreased. The VFAs constituted a major component of the accumulated dissolved organic matter, which reached a maximum of 0.5-0.7 mg soluble COD per mg VS from the three sludge types.


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.


Sign in / Sign up

Export Citation Format

Share Document