Utilization of the nucleic acids of<i>Escherichia coli</i>and rumen bacteria by sheep

Smith, Robert C.; Moussa, N.M.; Hawkins, George

doi:10.1079/bjn19740106

Cited by 29 publications

(10 citation statements)

References 12 publications

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“…This indicates that more than 60% of absorbed purine-N can be metabolized within the body pool in sheep. The rate of utilization of purine bases from microbial NA for tissue NA and nucleotide biosynthesis may be fairly high because, owing to much supply via the intestinal tract, sheep seem to have little need for a de novo synthesis pathway Smith et al 1974). The source of NA may be of importance in this respect.…”

Section: Discussionmentioning

confidence: 99%

The effect of changes in the intestinal flow of nucleic acids on allantoin excretion in the urine of Sheep

1980

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SUMMARYThree ewes were intraduodenally infused with yeast RNA (15, 20 and 30 g/day) or control solutions for 3 days and the net changes in urinary allantoin excretion determined. Four mature wethers fitted with a re-entrant cannula in the proximal duodenum were fed two levels (0·66 and 1 × maintenance) of pelleted lucerne hay. Allantoin excretion was compared with total nucleic acid (NA) flow in the small intestine.The average proportion of the recovery of the infused RNA-N dose as urinary allantoin–N amounted to 0·119 ± 0·0046. The values of the net increase of allantoin-N (Y, g/day) above control levels were highly significantly correlated (n = 12, r = 0·98) with amounts of RNA-N infused (X, g/day): y = 0·1185 (± 0·0086) X–0·004 (P < 0·001). The average ratio of urinary allantoin-N to NA-N passing the duodenum during 24 h was 0·173. A difference between the two conversion factors is discussed in relation to endogenous allantoin excretion and purine base composition of yeast and bacterial RNA.

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Section: Discussionmentioning

confidence: 99%

The effect of changes in the intestinal flow of nucleic acids on allantoin excretion in the urine of Sheep

1980

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“…In an in vivo experiment using RNA (adenine or guanine) labeled with 14 C, it was shown that NA are directly incorporated into body tissues, such as the liver, kidney and spleen (Smith et al . 1974).…”

Section: Absorption Of Na In Small Intestinementioning

confidence: 99%

Metabolism of microbial nitrogen in ruminants with special reference to nucleic acids

Fujihara¹,

Shem²

2011

Animal Science Journal

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Characteristically the metabolism of microbial nitrogen (N) compounds in ruminants involves the degradation of dietary N and synthesis of microbial protein (MP), compounds including a small amount of peptides and free amino acids, which may account for 75-85% of total N and the remainder are nucleic acids (NA: DNA and RNA). Generally rumen microbes contain 10-25% NA-N of the total N while 70-80% is in the form of RNA. This paper describes the degradation and synthesis of NA in the rumen and their fate in the lower digestive tracts. Their physiological and nutritional significance in different types of ruminant animals is also discussed. The research works on NA metabolism in ruminants has been mainly on metabolism of purines after rumen microbial digestion and absorption in the lower gut. Subsequently, the fate of absorbed purines has been intensively investigated to assess the extent of MP synthesis in the rumen. The method for predicting ruminal synthesized MP and subsequently digested MP has been proposed using urinary purine derivative (PD) excretion in sheep and cattle fed on ordinary feed. The latter approach has now been adopted for calculation of protein supply in some feeding standards, although there are still difficulties in predicting representative samples of rumen microbes, and also uncertainties in variations of non-renal and endogenous purine losses.

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“…Since the proportion of amino acid N (AA-N) and nucleic acid-N (NA-N) account for approximately 0.80 and 0.15 of the N contained in rumen micro-organisms (RMO) respectively, separate estimates of their true digestibility are required for new systems of protein evaluation (see Agricultural Research Council, 1980) since each fraction has a different nutritive value (Smith et al 1974;Peers, 1977;Razzaque et al 1981). In order to proceed further to state the AA requirement of ruminants precisely it is also necessary to estimate the digestibility of each AA from RMO since this is the main protein source for ruminants.…”

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confidence: 99%

The nutritive value of rumen micro-organisms in ruminants

Storm¹,

Brown²,

Ørskov³

1983

Br J Nutr

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1. An experiment was conducted with three sheep maintained entirely by intragastric nutrition to estimate the digestibility of isolated individual constituents and amino acids (AA) of rumen micro-organisms (RMO) in the small intestine.2. Five levels of RMO were infused into the abomasum. The apparent and true disappearance of the individual components were measured by regression of abomasal input on the passage at the ileum. In order to proceed further to state the AA requirement of ruminants precisely it is also necessary to estimate the digestibility of each AA from RMO since this is the main protein source for ruminants. The present paper describes the estimation by regression analysis of the true digestibilities of total N, total AA-N, RNA, DNA and nineteen individual AA of RMO and the endogenous losses of these substances in the small intestine of three sheep sustained entirely by a constant intraruminal infusion of volatile fatty acids (VFA) and minerals and abomasal infusion of five different amounts of RMO. A preliminary account of some of this work has been given previously (Storm & Orskov, 1982). MATERIALS A N D METHODS Animals.Three Suffolk x (Finnish Landrace x Dorset Horn) wether lambs, weighing between 27 and 36 kg, were used.Each animal was surgically prepared with a permanent rumen cannula and an abomasal catheter, as previously described by Orskov et al. (1979). Furthermore, the animals were fitted with a simple T-piece cannula in the distal part of the ileum, 15-20 mm anterior to the ileo-caecal junction. The open end of the ileal cannula was exteriorized midway up on the right flank of the animal and a plastic loop arranged on each side of the cannulas according to Hecker (1974) so that total collection of ileal fluid was possible.Infusion treatment. After the lambs had been fitted with the cannulas they were kept in individual metabolism cages for 2 weeks before intragastric infusion was commenced. The infusion regimen was then gradually introduced over 10-12 d. Clean drinking water was freely available at all times. 16-2

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Utilization of the nucleic acids ofEscherichia coliand rumen bacteria by sheep

Cited by 29 publications

References 12 publications

The effect of changes in the intestinal flow of nucleic acids on allantoin excretion in the urine of Sheep

The effect of changes in the intestinal flow of nucleic acids on allantoin excretion in the urine of Sheep

Metabolism of microbial nitrogen in ruminants with special reference to nucleic acids

The nutritive value of rumen micro-organisms in ruminants

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