Amino Acid Composition of Rumen Organisms

Purser, D. B.; Buechler, Suzanne M.

doi:10.3168/jds.s0022-0302(66)87791-3

Cited by 166 publications

(39 citation statements)

References 8 publications

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“…The DAP content of different species varies widely (Synge 1953;Purser and Buechler, 1966) and assumptions must be made when the weight is being converted to a mixed population. RNA has also been used as a microbial marker but even when it is rapidly degraded, as in the rumen, enough contamination remains from the diet to affect results (Smith et al, 1978); mucosal cells may also contribute to contamination.…”

Section: Discussionmentioning

confidence: 99%

The Microbial Contribution to Human Faecal Mass

Stephen

Cummings

1980

Journal of Medical Microbiology

480

231

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Section: Discussionmentioning

confidence: 99%

The Microbial Contribution to Human Faecal Mass

Stephen

Cummings

1980

Journal of Medical Microbiology

480

231

View full text Add to dashboard Cite

“…Amino acid composition of bacterial protein isolated from the rumen is in ear lier experiments found to be relatively constant (Purser and Buechler, 1966;Ber gen et al, 1968). More recent research on composition of bacterial protein isolated from the rumen originating from many different dietary treatments have revealed major differences in the bacterial amino acid composition as shown in Table 2.…”

Section: Amino Acid Composition and Digestibility Of Bacterial Proteinmentioning

confidence: 99%

Supply of the dairy cow with amino acids from dietary protein

Hvelplund¹,

Misciattelli²,

Weisbjerg³

2001

J. Anim. Feed Sci.

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Microbial protein produced in the rumen is not sufficient to meet the requirement for amino acids of the high producing dairy cow. The microbial protein thus need to be supplemented with a certain amount of undegraded protein which match the microbial protein both quantitatively and qualitative ly to enable an efficient utilization for milk production. This paper summarizes findings with respect to amino acid composition and digestibility of microbial amino acids. The main emphasis is however on recent findings with respect to degradability and digestibility of individual amino acids in feed proteins. The results seem to indicate that degradability and digestibility estimates obtained for nitro gen may not always apply to individual amino acids. It is concluded that more research is needed to identify the ideal profile of the amino acids absorbed from the intestine of lactating cows. Results of such efforts are needed to compose an ideal protein supplement eventually by using protected amino acids to balance the microbial protein to meet the amino acid requirement of dairy cattle with a minimum of rumen undegraded protein.

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“…The other essential AA's were not affected by treatment (P ≥ 0.22), indicating that the duodenal essential AA pattern, predominantly derived from microbial protein, is relatively constant, irrespective of protein source. Purser & Buechler (1966) also reported little variation in the AA composition of 22 strains of pure cultures of rumen organisms specifically selected for their differing substrate utilisation characteristics. Supporting evidence by Bergen et al (1968) and Martin et al (1996) also indicated that the AA composition of rumen microorganisms was independent of dietary changes.…”

Section: Resultsmentioning

confidence: 97%

The effect of rumen degradable protein level and source on the duodenal essential amino acid profile of sheep

Nolte¹,

Ferreira²

2007

SA J. An. Sci.

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Two trials were conducted to determine the effects of rumen degradable protein (RDP) level and source on the duodenal essential amino acid (AA) composition of Dohne Merino wethers. The animals had ad libitum access to wheat straw (32 g crude protein (CP)/kg DM; 742 g neutral detergent fibre (NDF)/kg DM) and water. In the first experimental treatments casein provided 0, 40, 80, 120 and 160 g supplemental RDP/d. In experiment two, urea-nitrogen replaced 0, 25, 50, 75 and 100% of the true protein in the isonitrogenous treatments. Expressing essential AA concentration as a percentage of duodenal protein indicated that increasing RDP levels tended to decrease arginine, but significantly increased tryptophan concentrations. Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine and total essential AA concentrations were not affected by dietary RDP level. Increasing the urea-N content of RDP supplements significantly decreased isoleucine, leucine, lysine, phenylalanine, tryptophan, valine and total essential amino acid (TEAA) concentrations. Histidine and threonine proportions also tended to decrease with higher non-protein N levels. When the essential AA profile is expressed in relation to lysine, the concentrations of histidine, leucine, phenylalanine and threonine decreased significantly. Arginine and valine showed a decreasing trend and tryptophan increased significantly as RDP levels were raised. The largest differences appeared between 0 and 40 g RDP supplementation, while the AA patterns for the rest of the treatments remained relatively constant. Substituting urea for true RDP induced a variable response in arginine and isoleucine, but did not affect any of the other AA's. Increasing RDP intakes significantly increased the duodenal flow of every essential AA, except arginine, and showed a strong tendency to increase TEAA flow as well. Replacing true RDP with urea significantly reduced the flow of methionine and tryptophan and also tended to decrease lysine availability in the duodenum. Individual AA and TEAA flow to the duodenum were also numerically decreased by a minimum of 34% as urea-N was increased. It appears that the qualitative duodenal essential AA profile in sheep fed low quality forages is relatively insensitive to RDP level or source. The daily essential AA flow to the duodenum seems to be compromised by urea substitution for true RDP.

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Amino Acid Composition of Rumen Organisms

Cited by 166 publications

References 8 publications

The Microbial Contribution to Human Faecal Mass

The Microbial Contribution to Human Faecal Mass

Supply of the dairy cow with amino acids from dietary protein

The effect of rumen degradable protein level and source on the duodenal essential amino acid profile of sheep

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