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A technique for measuring the biological availability of copper of sheep, sing hypocupraemic ewes

Published online by Cambridge University Press:  24 July 2007

N. F. Suttle
N. F. Suttle
Affiliation:
Moredun Research Institute, Gilmerton Road, Edinburgh EH17 7JH
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Abstract

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1. Ewes were made hypocupraemic by feeding a copper-deficient diet and the subsequent responses in plasma Cu obtained when Cu was added to the diet were used to assess the biological availability of the added Cu.

2. The uniformity of responses was investigated by repleting thirty-six ewes for 33 d on two occasions with a standard diet containing 5.0 mg Cu/kg dry matter (DM). The mean responses were 0.36 and 0.33 mg/l and the coefficient of variation was approximately 53% on each occasion. The marked individual differences were largely repeatable, the correlation coefficient (r) within individuals being 0.68 (P < 0.001).

3. A dose: response relationship was investigated by giving five groups of seven ewes diets containing 2.7, 4.2, 5.7, 7.2 or 8.7 mg Cu/kg DM for 33 d. Each increment in dietary Cu above 4.2 mg/kg significantly increased the response in plasma Cu. The relationship between plasma Cu response (y, mg/l) and Cu intake (x, mg/d) after 21 d was y = 0.0871x−0.250 (r = 0.99; 3 df).

4. The source of individual variation was investigated by comparing the responses of three ‘slow’ and three ‘fast’ responding ewes from Expt 1 to Cu given as a continuous intravenous infusion at rates of 0.05–0.3 mg/d. The relationship between plasma Cu response (y) and infusion rate (x, mg/d) after 17 d, was y = 2.135x –0.156 (r = 0.86; P < 0 .001). The regression coefficients for ‘slow’ and ‘fast’ responding ewes were similar, as was their metabolism of intravenous 64Cu, suggesting that the individual differences were due to differences in absorption rather than in the metabolism of absorbed Cu. Faecal endogenous Cu excretion was estimated to be 0.127 ± 0.019 (mean ± SE) mg/d.

5. The relative responses to oral and intravenous Cu were used to estimate the true availability of dietary Cu; in one experiment it was 4.1% and for individual ewes in another experiment, availabilities ranged from 4.5 to 11.4%. The figures are compared with assessments by conventional techniques.

6. It is concluded that the repletion technique provides a sensitive means of assessing the availability of Cu in ruminant diets.

Type
General Nutrition
Information
British Journal of Nutrition , Volume 32 , Issue 2 , September 1974 , pp. 395 - 405
Copyright
Copyright © The Nutrition Society 1974

References

REFERENCES

Abdellatif, A. M. M. (1968). Versl. landbouwk. Onderz. Ned. no. 709, p. 76.Google Scholar
Adamson, A. H., Valks, D. A., Appleton, M. A. & Shaw, W. B. (1969). Vet. Rec. 85, 368.CrossRefGoogle Scholar
Allcroft, R. & Lewis, G. (1957). J. Sci. Fd Agric. 8, 897.Google Scholar
Bingley, J. B. (1959). J. agric. Fd Chem. 7, 269.CrossRefGoogle Scholar
Chinard, F. P. (1951). Meth. med. Res. 4, 38.Google Scholar
Dick, A. T. (1953). Aust. vet. J. 29, 233.CrossRefGoogle Scholar
Garrido, M. L. (1964). Analyst, Lond. 89, 61.CrossRefGoogle Scholar
Hainline, A. (1958). In Standard Methods of Clinical Chemistry Vol. 2, p. 49 [Seligson, D., editor]. New York: Academic Press.Google Scholar
Hartmans, J. & van der Grift, J. (1965). Jaarb. Inst. biol. scheik. Onderz. LandbGewass. p. 145.Google Scholar
Hogan, K. G., Money, D. F. L. & Blayney, A. (1968). N.Z. Jl agric. Res. 11, 435.CrossRefGoogle Scholar
Hogan, K. G., Money, D. F. L. & Walker, R. S. (1971). N.Z. Jl agric. Res. 14, 132.CrossRefGoogle Scholar
Hogan, P. K., Ris, D. R. & Hutchinson, A. J. (1966). N.Z. JI agric. Res. 9, 691.CrossRefGoogle Scholar
Kirchgessner, M. & Grassmann, E. (1970). Z. Tierphysiol. Tierernähr. Futtermittelk. 26, 340.CrossRefGoogle Scholar
Mills, C. F. (1957). J. Sci. Fd Agric. 8, 888.Google Scholar
Mills, C. F. & Williams, R. B. (1971). Proc. Nutr. Soc. 30, 83.CrossRefGoogle Scholar
Mottershead, B. E. (1971). Lab. Pract. 20, 483.Google Scholar
Murty, V. N. (1957). J. scient. ind. Res. C 16, 121.Google Scholar
Rice, E. W. (1962). Analyt. Biochem. 3, 452.CrossRefGoogle Scholar
Schulze, M. D., Elvehjem, C. A. & Hart, E. B. (1936). J. biol. Chem. 115, 453.CrossRefGoogle Scholar
Smith, B. S. W., Field, A. C. & Suttle, N. F. (1968). J. comp. Path. 78, 449.CrossRefGoogle Scholar
Smith, B. S. W. & Wright, H. (1974). Clinica chim. Acta 50, 359.CrossRefGoogle Scholar
Snedecor, G. W. (1956). Statistical Methods Applied to Experiments in Agriculture and Biology 5th ed., p. 291. Ames, Iowa: Iowa State College Press.Google Scholar
Suttle, N. F. (1968). In Proceedings of 2nd Nutrition Conference of Feed Manufacturers, Nottingham p. 150 [Swan, H. and Lewis, D., editors’. London: J. and A. Churchill.Google Scholar
Suttle, N. F. (1974). Proc. 2nd int. Symp. Trace Element Metabolism in Animals, Wisconsin. (In the Press.)Google Scholar
Suttle, N. F. & Field, A. C. (1968). J. comp. Path. 78, 351.CrossRefGoogle Scholar
Underwood, E. J. (1971). Trace Elements in Human and Animal Nutrition 3rd ed. p. 67. New York: Academic Press.Google Scholar
Vanderveen, J. E. & Keener, H. A. (1964). J. Dairy Sci. 47, 1224.CrossRefGoogle Scholar
Wiener, G. & Field, A. C. (1970). In Trace Element Metabolism in Animals p. 92 [Mills, C. F., editor]. Edinburgh: E. and S. Livingstone.Google Scholar