Gas and Volatile Fatty Acid Production at Different Rates of Rumen Microbial Protein Synthesis In Vitro

Abstract This study evaluated the effect of combinations of feed-grade urea and slow-release urea (SRU) on fermentation and microbial protein synthesis within two artificial rumens (Rusitec) fed a finishing concentrate diet. The experiment was a completely randomized, dose–response design with SRU substituted at levels of 0% (control), 0.5%, 1%, or 1.75% of dry matter (DM) in place of feed-grade urea, with four replicate fermenters per dosage. The diet consisted of 90% concentrate and 10% forage (DM basis). The experiment was conducted over 15 d, with 8 d of adaptation and 7 d of sampling. Dry matter and organic matter disappearances were determined after 48 h of incubation from day 9 to 12, and daily ammonia (NH3) and volatile fatty acid (VFA) production were measured from day 9 to 12. Microbial protein synthesis was determined on days 13–15. Increasing the level of SRU quadratically affected total VFA (Q, P = 0.031) and ammonia (Q, P = 0.034), with a linear increment in acetate (L, P = 0.01) and isovalerate (L, P = 0.05) and reduction in butyrate (L, P = 0.05). Disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) was quadratically affected by levels of SRU, plateauing at 1% SRU. Inclusion of 1% SRU resulted in the highest amount of microbial nitrogen associated with feed particles (Q, P = 0.037). Responses in the efficiency of microbial protein synthesis fluctuated (L, P = 0.002; Q, P = 0.001) and were the highest for 1% SRU. In general, the result of this study showed that 1% SRU in combination with 0.6% urea increased NDF and ADF digestibility and total volatile fatty acid (TVFA) production.

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The use of the in vitro fermentation technique to estimate the digestible energy content of some Egyptian forages: III. The effect of periodical renewal of medium on volatile fatty acid production and cellulose digestion in vitro as criteria of energy content

The Journal of Agricultural Science ◽

10.1017/s0021859600020049 ◽

1969 ◽

Vol 73 (3) ◽

pp. 431-436

Author(s):

K. El-Shazly ◽

M. A. Naga ◽

M. A. Abaza ◽

A. R. Abou Akkada

Keyword(s):

Fatty Acid ◽

Acid Production ◽

Volatile Fatty Acid ◽

Dry Matter ◽

Energy Content ◽

Correlation Coefficients ◽

Fatty Acid Production ◽

Cellulose Digestion ◽

Digestible Energy

SUMMARYEleven forages of known digestible energy/kg dry matter (Naga & el-Shazly, 1963) were used in in vitro fermentation experiments. Direct determinations of digestible energy (D.E./kg D.M.) using the bomb calorimeter were also included, and the values were corrected for gas losses.In vitro fermentations were interrupted every 12, 8 and 6 h, the medium was renewed and volatile fatty acid (VFA) production and cellulose digestion were estimated. Volatile fatty acid production from legumes was high early in the fermentation periods and became lower in later periods. Non-legumes behaved in an opposite manner.Significant negative correlation coefficients between VFA production and D.E./kg D.M. were found for legumes at later intervals of fermentation, while correlation coefficients for non-legumes lost their significance at later periods of fermentation.Digestible energy/kg dry matter could best be predicted for legumes from the volatile fatty acids produced in the second 12 h fermentation period or from the sum of the VFA produced in second, third and fourth 6 h periods of fermentation.

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Effects of Antibiotics on Apparent Lactate and Volatile Fatty Acid Production: In Vitro Rumen Fermentation Studies

Journal of Animal Science ◽

10.2527/jas1977.452385x ◽

1977 ◽

Vol 45 (2) ◽

pp. 385-392 ◽

Cited By ~ 8

Author(s):

David K. Beede ◽

Stanley D. Farlin

Keyword(s):

Fatty Acid ◽

Acid Production ◽

Volatile Fatty Acid ◽

Rumen Fermentation ◽

Fatty Acid Production ◽

In Vitro Rumen Fermentation

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EFFECTS OF THIAMINE INHIBITORS ON CELLULOSE DIGESTION AND VOLATILE FATTY ACID PRODUCTION IN ARTIFICIAL RUMEN FERMENTATIONS

Canadian Journal of Animal Science ◽

10.4141/cjas65-019 ◽

1965 ◽

Vol 45 (2) ◽

pp. 99-104 ◽

Cited By ~ 1

Author(s):

L. P. Milligan ◽

J. M. Asplund ◽

A. R. Robblee

Keyword(s):

Fatty Acid ◽

Acid Production ◽

Volatile Fatty Acid ◽

Fermentation Medium ◽

Rumen Fermentation ◽

Fatty Acid Production ◽

Rumen Microorganisms ◽

Cellulose Digestion ◽

Structural Analogues

The effect of the inclusion of thiamine inhibitors in a rumen fermentation medium on cellulose digestion and volatile fatty acid production by rumen microorganisms in vitro was studied. The addition of the structural analogues oxythiamine and neopyrithiamine to the fermentation medium at concentrations up to 4000 μM and 2000 μM, respectively, did not influence cellulose digestion or volatile fatty acid production. The addition of thiopental and hexetidine to the fermentation medium affected both cellulose digestion and volatile fatty acid production. Some inhibition of cellulose digestion and of volatile fatty acid production occurred with concentrations of thiopental and hexetidine in the fermentation medium as low as 720 μM and 15 μM respectively.

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