The Digestion of Protein and Nitrogenous Compounds in Ruminants

Chalmers, Margaret I.; Synge, R. L. M.

doi:10.1016/s0065-3233(08)60205-3

Cited by 66 publications

(23 citation statements)

References 114 publications

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“…Early work produced the general rule that protein breakdown in the rumen is proportional to solubility (Chalmers and Synge, 1954;Henderickx and Martin, 1963;Henderickx, 1976), but subsequent research has shown that other properties are also important (Kaufmann and Lupping, 1982). Protein is the most abundant source of nitrogen in most ruminant diets.…”

Section: Protein Degradationmentioning

confidence: 99%

The Rumen Microbial Ecosystem

Hobson¹,

Stewart²

1997

347

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Section: Protein Degradationmentioning

confidence: 99%

The Rumen Microbial Ecosystem

Hobson¹,

Stewart²

1997

347

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“…A large proportion of ammonia produced in the rumen may be absorbed if its incorporation into microbial protein is reduced by lack of energy for microbial growth (Chalmers and Synge, 1954;Lewis, 1957;el-Shazly, 1958;Tagari, Dror, Ascarelli and Bondi, 1964;Abou Akkada and Osman, 1967). A large proportion of ammonia produced in the rumen may be absorbed if its incorporation into microbial protein is reduced by lack of energy for microbial growth (Chalmers and Synge, 1954;Lewis, 1957;el-Shazly, 1958;Tagari, Dror, Ascarelli and Bondi, 1964;Abou Akkada and Osman, 1967).…”

Section: Moredun Research Institute Edinburgh Eh17 7jhmentioning

confidence: 99%

An assessment of the value of plasma urea nitrogen and albumin concentrations as monitors of the protein status of sheep

Sykes

1978

BSAP Occas. Publ.

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There are two basic aspects of protein metabolism the measurement of which may assist in improving sheep management, first, the extent to which the daily requirement of the animal is met and secondly, the extent of depletion of body reserves. The need for the latter assessment arises because in some situations in which nutrient requirement and supply are not in phase it is often desirable for economic reasons to utilize the capacity of the animal to deplete and replete its body reserves.Of the major nutrients, the prediction of energy metabolism from plasma parameters has received most attention. Thus the work of Annison (1960), Reid and Hinks (1962), West and Annison (1964) relating Free Fatty Acid (FFA) concentration to rate of fat mobilization allowed the prediction not only of energy balance but also rate of energy reserve mobilisation in controlled nutritional situations (Russel, Doney and Reid, 1967; Russel and Honey, 1969; Robinson, Fraser and Bennett, 1971).

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“…The concentration of free amino acids in the rumen is at all times low (Chalmers & Synge, 1954b), but breakdown products of the amino acids, ammonia (McDonald, 1948(McDonald, , 1952) and volatile fatty acids (el-Shazly, 1952a) are found in high concentration when the diet of the animal contains adequate and suitable protein. Both the prior treatment and the nature of the protein affect the amount of breakdown products found.…”

mentioning

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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The Digestion of Protein and Nitrogenous Compounds in Ruminants

Cited by 66 publications

References 114 publications

The Rumen Microbial Ecosystem

The Rumen Microbial Ecosystem

An assessment of the value of plasma urea nitrogen and albumin concentrations as monitors of the protein status of sheep

Proteolysis by Rumen Micro-organisms

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