Degradation of protein in the rumen of the sheep. 2. The action of rumen micro-organisms on amino-acids

El-Shazly, K.

doi:10.1042/bj0510647

Cited by 173 publications

(52 citation statements)

References 19 publications

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“…The ratio of the sum of the branched chain acids plus valeric to the sum of acetic, propionic and butyric acids (AAE) was closely related to the CP concentration (Fig 2), except for CC of L4 (see below). This is in agreement with the results of EI Shazly, 15 who found higher concentrations of the branched chain acids in vivo for higher-protein rations.…”

Section: 3supporting

confidence: 93%

Effects of ageing on thein vitro fermentation of cell walls and cell contents of entire, fractionated and composite leaves of Italian ryegrass

Williams

Oostdam

Groot

et al. 2000

J. Sci. Food Agric.

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Section: 3supporting

confidence: 93%

Effects of ageing on thein vitro fermentation of cell walls and cell contents of entire, fractionated and composite leaves of Italian ryegrass

Williams

Oostdam

Groot

et al. 2000

J. Sci. Food Agric.

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“…Ammonia production in particular appeared to occur by different mechanisms in the bacteria and the protozoa, and it is suggested that much of the continuing ammonia production in the rumen in the absence of readily attacked protein might be due to the endogenous metabolism of rumen protozoa; ammonia is known to be the major end product of nitrogen metabolism in some freeliving ciliate protozoa (Kidder & Dewey, 1951). El-Shazly (1952b) found that the capacity of rumen bacteria to deaminate amino acids depended on the prcsence in the diet of the host animal of a readily attacked protein. This does not appear to be the case for the power to cause proteolysis, except perhaps in so far as a high protein diet will usually support a more numerous microbial population.…”

Section: Discussionmentioning

confidence: 99%

Proteolysis by Rumen Micro-organisms

Warner¹

1956

Journal of General Microbiology

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SUMMARY : Toluene-treated washed suspensions of rumen bacteria break down proteins largely to amino acids ; in the absence of toluene bacterial deaminases are active. Unlike the deaminases, the presence of proteases does not depend, to any great extent, on the presence of readily attacked protein in the diet of the host animal. Extracts of acetone-dried powders of the bacteria also show proteolytic activity. Rumen protozoa are also proteolytic, and ammonia appears to be the end product of their nitrogen metabolism. Ammonia production due to the protozoa is not as sensitive to toluene as is the case with bacteria. Much of the ammonia production in the rumen in the absence of substrate appears to be due to the endogenous metabolism of the protozoa. Extracts of acetone powders, and extracts prepared by simple freezing and thawing of the protozoa, contain active proteases.In an artificial rumen apparatus it was shown that when digestion was complete, about half the N and C of added casein could be recovered as ammonia and volatile fatty acids respectively. Most of the remainder could not be accounted for analytically, and was presumed to be used for microbial growth, which had occurred. When starch or some other polysaccharides were added to the artificial rumen apparatus as well as casein, the production of ammonia was lowered. This was shown not to be due to any effect on proteolysis or deamination, and was presumed to be due to the increased utilization for microbial growth of some breakdown product of casein.From a t least the time of Zuntz (1891), it has been suspected that microorganisms of the rumen split the proteins fed to the host animal; there has been, however, little unequivocal direct evidence for this proteolytic activity. Schlottke (1936) showed in vitro that glycerol extracts of rumen protozoa contained a protease active a t pH c. 6.1, and also a dipeptidase, but was unable to find much activity in glycerol extracts of rumen bacteria. However, Sym (1938) showed active proteolysis a t pH 6.3 by suspensions of rumen bacteria and of protozoa, and also by extracts of acetone powders of these microorganisms; he found peptidase activity weak in his preparations. Both these authors found little or no free protease in the supernatant rumen liquor. Nikitin (

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“…Short branched-chain fatty acids arise from deamination of branched-chain amino acids by rumen microorganisms [31] or by carboxylation of propionyl-CoA to form methylmalonyl-CoA [32]. These branched-chain fatty acids can then be incorporated during fat synthesis in ruminants to form longer chain branched-chain fatty acids [33].…”

Section: Branched-chain Fatty Acidsmentioning

confidence: 99%

Comparing Subcutaneous Adipose Tissue in Beef and Muskox with Emphasis on trans 18:1 and Conjugated Linoleic Acids

Dugan

Kramer

Robertson

et al. 2007

Lipids

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Muskox (Ovibos moschatus) are ruminant animals native to the far north and little is known about their fatty acid composition. Subcutaneous adipose tissue (backfat) from 16 wild muskox was analyzed and compared to backfat from 16 barley fed beef cattle. Muskox backfat composition differed substantially from beef and the most striking difference was a high content of 18:0 (26.8 vs. 9.77%). This was accompanied by higher levels of most other saturated fatty acids except beef had more 16:0. Muskox backfat also had a lower level of cis-18:1 and this was related to a lower expression of steroyl-CoA desaturase mRNA. Beef backfat had a higher level of total trans-18:1 (4.25 vs. 2.67%). The most prominent trans-18:1 isomers in beef backfat were 10t-18:1 (2.13%) and 11t-18:1 (0.77%) whereas the most prominent isomers in muskox backfat were 11t-18:1 (1.41%), 13t/14t- (0.27%) and 16t-18:1 (0.23%). The total conjugated linoleic acid (CLA) content was higher in beef backfat than muskox (0.67 vs. 0.50%) with 9c,11t-18:2 as the most abundant CLA isomer. The second most abundant CLA isomer in beef backfat was 7t,9c-18:2 (0.10%) whereas in muskox it was 11t13c-18:2 (0.04%). Muskox backfat had a higher content of 18:3n-3 and its elongation and desaturation products 20:5n-3, 22:5n-3 and 22:6n-3 and a lower n-6/n-3 ratio. Overall, the high forage diet of muskox seemed to produce a healthier fatty acid profile and highlighted the need to develop feeding strategies for intensively raising beef that will not negatively impacting fatty acid composition.

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Degradation of protein in the rumen of the sheep. 2. The action of rumen micro-organisms on amino-acids

Cited by 173 publications

References 19 publications

Effects of ageing on thein vitro fermentation of cell walls and cell contents of entire, fractionated and composite leaves of Italian ryegrass

Effects of ageing on thein vitro fermentation of cell walls and cell contents of entire, fractionated and composite leaves of Italian ryegrass

Proteolysis by Rumen Micro-organisms

Comparing Subcutaneous Adipose Tissue in Beef and Muskox with Emphasis on trans 18:1 and Conjugated Linoleic Acids

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