A resin-based method for the preparation of molecular nitrogen for 15N analysis from urinary and plasma components

Read, W. W. C.; Harrison, R. A. P.; Halliday, D.

doi:10.1016/0003-2697(82)90442-0

Cited by 42 publications

(15 citation statements)

References 10 publications

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“…(1950). Plasma samples for 15 N enrichment determination were prepared according to the following method: 0.3 ml of 10% (w/v) trichloroacetic acid (TCA) was added to 0.5 ml of plasma to separate the soluble from the insoluble TCA fractions (Read et al., 1982). The mix was kept overnight at 4 °C.…”

Section: Methodsmentioning

confidence: 99%

ORIGINAL ARTICLE: The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats

Zhou

Tan

Tang

et al. 2010

Journal of Animal Physiology and Animal Nutrition

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The effect of dietary methionine (Met) levels on endogenous N and amino acids (AA) flows at different part of the digestive tract of growing goats was determined using a (15)N isotope dilution technique. Three goats (25 ± 2.5 kg) were fitted with the ruminal, duodenal and ileal cannulae and allocated to three dietary treatments in a 3 × 3 Latin square design. The dietary treatments consisted of a total mixed ration containing three levels of Met (0.15%, 0.25% and 0.35%) respectively. It was found that at 0.15% Met level, the lowest flow in endogenous N and total AA at the duodenum and ileum occurred. The endogenous N secretion contributed to 26% and 23% of the duodenal and ileal total N flows, respectively, and the proportions were not affected by the dietary Met levels. The duodenal and ileal flows of endogenous total AA were 11.1, 11.8, 11.3 g/d and 2.9, 3.9, 4.1 g/d respectively. The average real digestibility of N was 65%, 87% and 95% in the forestomach, intestine and whole digestive tract respectively.

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Section: Methodsmentioning

confidence: 99%

ORIGINAL ARTICLE: The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats

Zhou

Tan

Tang

et al. 2010

Journal of Animal Physiology and Animal Nutrition

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“…From the tube, 31 mmol of urea was pipetted into a column containing 2 ml of Dowex resin to remove any remaining ammonia, and the effluent was discarded. Deionized water (20 ml) was added to the column, and the effluent was discarded (Read et al, 1982). An additional 10 ml of deionized water was added to the column, and the effluent was retained.…”

Section: Laboratory Analysesmentioning

confidence: 99%

Methodology for concurrent determination of urea kinetics and the capture of recycled urea nitrogen by ruminal microbes in cattle

Wickersham

Titgemeyer

Cochran

2009

Animal

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We measured the incorporation of recycled urea-nitrogen (N) by ruminal microbes, using five ruminally and duodenally fistulated steers (237 kg) fed low-quality grass hay (47 g crude protein/kg dry matter (DM)). Three received 1 kg/day of soybean meal (SBM) and two received no supplemental protein (control). The experiment was 15 days long. Background enrichments of15N were measured on day 9 and continuous jugular infusion of 0.12 g/day [15N15N]urea began on day 10. Daily samples of urine, feces, ruminal bacteria and duodenal digesta from days 10 through 14 were used to determine plateaus in15N enrichment. Duodenal and bacterial samples collected on day 15 were used to measure duodenal N flows. Bacterial N flow was calculated as duodenal N flow multiplied by duodenal15N enrichment divided by bacterial15N enrichment. Bacterial N from recycled urea-N was calculated as bacterial N flow multiplied by bacterial15N enrichment divided by urinary urea15N enrichment. Urinary enrichment of [15N15N]urea plateaued within 24 h, whereas14N15N urea plateaued within 48 h of [15N15N]urea infusion. Bacteria reached a plateau in15N enrichment within 24 h and duodenal samples within 48 h. Urea production was 17.6 g of urea-N/day for control and 78.0 g/day for SBM. Gut entry was 0.99 g of urea-N/g of urea-N produced for control and 0.87 g/g for SBM. Incorporation of recycled N into microbial N was 9.0 g of N/day for control and 23.0 g/day for SBM. Recycled urea-N accounted for 0.33 g of N/g of microbial N at the duodenum for control and 0.27 g/g for SBM. Our methods allowed measurement of incorporation of recycled urea-N into ruminal microbial N.

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“…The 15 N enrichments of urea N and NH 3 were measured with an isotope ratioing mass spectrometer (Finnigan MAT-251) after preparation of the samples and adsorption of NH 3 onto resin according to the methods described by Read et al (1982). Briefly, free ammonium N in neutralized urine was adsorbed to Dowex AG50WX8 resin (100-200 mesh, Na-K form).…”

Section: Analysesmentioning

confidence: 99%

Influence of dietary lysine level on whole-body protein turnover, plasma IGF-I, GH and insulin concentration in growing pigs

Ren

Zhao

2007

Livestock Science

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A resin-based method for the preparation of molecular nitrogen for 15N analysis from urinary and plasma components

Cited by 42 publications

References 10 publications

ORIGINAL ARTICLE: The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats

ORIGINAL ARTICLE: The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats

Methodology for concurrent determination of urea kinetics and the capture of recycled urea nitrogen by ruminal microbes in cattle

Influence of dietary lysine level on whole-body protein turnover, plasma IGF-I, GH and insulin concentration in growing pigs

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