Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-14T22:39:20.693Z Has data issue: false hasContentIssue false
  • English
  • Français

Partition of circulating triglycerides between formation of milk fat and other metabolic pathways in sheep

Published online by Cambridge University Press:  27 March 2009

R. F. Glascock ,
R. W. Smith  and
Ann Walsh
R. F. Glascock
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
R. W. Smith
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Ann Walsh
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Get access Rights & Permissions [Opens in a new window]

Summary

An emulsion of [3H]triglycerides was used to investigate how circulating triglycerides are partitioned between milk fat, body fat and use as an energy source in lactating sheep. Immediately after intravenous injection of the emulsion the radioactivity in the blood was predominantly associated with the triglycerides of the fraction that contained chylomicrons and very low density lipoproteins. The radioactive triglyceride was used both as a precursor of milk fat and as a source of energy. The proportions utilized for these two purposes were determined experimentally and the amount retained in the carcass lipids was found by difference. In separate control experiments with nonlactating sheep the total radioactivity in the body lipids was determined by carcass analysis. This total together with that accounted for by oxidation amounted to 98% of the total radioactivity injected. These results established that the emulsion was a reliable model for the purpose intended.

The proportion of the labelled triglyceride that appeared in milk fat declined from 45% at 17 days after lambing to 8–10% at 73 days after lambing. The proportion that was oxidized was also lower in late lactation so that retention in carcass lipids was substantially increased at that time.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 101 , Issue 1 , August 1983 , pp. 33 - 38
Copyright
Copyright © Cambridge University Press 1983

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bauman, D. E. & Currie, W. B. (1980). Partitioning of nutrients during pregnancy and lactation: a review of mechanisms involving homeostasis and homeorhesis. Journal of Dairy Science 63, 1514–1529.CrossRefGoogle ScholarPubMed
Bergman, E. N., Havel, R. J., Wolfe, B. M. & Bøhmer, J. (1971). Quantitative studies of the metabolism of chylomicron triglyceride and cholesterol by liver and extra-hepatic tissues of sheep and dogs. Journal of Clinical Investigation 50, 1831–1839.CrossRefGoogle Scholar
Bishop, C., Davies, T., Glascock, R. F. & Welch, V. A. (1969). Studies on the origin of milk fat. A further study of bovine serum lipoproteins and an estimation of their contribution to milk fat. Biochemical Journal 113, 629–633.CrossRefGoogle Scholar
Brunzell, J. D., Hazzard, W. R., Porte, D. & Bierman, E. L. (1973). Evidence for a common, saturable, triglyceride removal mechanism for chylomicrons and very low density lipoproteins in man. Journal of Clinical Investigation 52, 1578–1585.CrossRefGoogle ScholarPubMed
Budtz-Olsen, O. E., Cleeve, J. D. & Oelrichs, B. A. (1961). Total body water in Merino and Romney Marsh sheep estimated by alcohol (ethanol) dilution. Australian Journal of Agricultural Research 12, 681–688.CrossRefGoogle Scholar
Florence, E. & Mitchell, K. G. (1972). A procedure for preparation of pig carcasses for chemical analysis with special reference to microanalysis. Proceedings of the British Society of Animal Production 1, 101–107.Google Scholar
Folch, J., Lees, M. & Sloane-Stanley, G. H. (1957). A simple method for the isolation and purification of total lipids from animal tissues. Journal of Biological Chemistry 226, 497–509.CrossRefGoogle ScholarPubMed
Glascock, R. F. & Welch, V. A. (1974). Contribution of the fatty acids of three low density serum lipoproteins to bovine milk fat. Journal of Dairy Science 57, 1364–1370.CrossRefGoogle ScholarPubMed
Glascock, R. F., Welch, V. A., Bishop, C., Davies, T., Wright, E. W. & Noble, R. C. (1966). An investigation of serum lipoproteins and of their contribution to milk fat in the dairy cow. Biochemical Journal 98, 149–156.CrossRefGoogle ScholarPubMed
Lascelles, A. K., Hardwick, D. C., Linzell, J. L. & Mepham, T. B. (1964). The transfer of [3H]stearic acid from chylomicra to milk fat in the goat. Biochemical Journal 92, 36–42.CrossRefGoogle ScholarPubMed
Palmquist, D. L. & Mattos, W. (1978). Turnover of lipoproteins and transfer to milk fat of dietary (1-earbon-14) linoleic acid in lactating cows. Journal of Dairy Science 61, 561–565.CrossRefGoogle Scholar
Puppione, D. L. (1978). Implications of unique features of blood lipid transport in the lactating cow. Journal of Dairy Science 61, 651–659.CrossRefGoogle ScholarPubMed
Robinson, D. S., Cryer, A. & Davies, P. (1975). The role of clearing-factor lipase (lipoprotein lipase) in the transport of plasma triglycerides. Proceedings of the Nutrition Society 34, 211–215.CrossRefGoogle ScholarPubMed
Singleton, W. S., Gray, M. A., Brown, M. L. & White, J. L. (1965). Chromatographically homogeneous lecithin from egg phospholipids. Journal of the American Oil Chemists' Society 42, 53–56.CrossRefGoogle ScholarPubMed
Vernon, R. G. (1980). Lipid metabolism in the adipose tissue of ruminant animals. Progress in Lipid Research 19, 23–106.CrossRefGoogle ScholarPubMed
Vernon, R. G., Clegg, R. A. & Flint, D. J. (1981). Metabolism of sheep adipose tissue during pregnancy and lactation. Biochemical Journal 200, 307–314.CrossRefGoogle ScholarPubMed
Zilversmit, D. B., Salky, N. K., Trumbull, M. L. & McCandless, E. L. (1956). The preparation and use of anhydrous fat emulsions for intravenous feeding and metabolic experiments. Journal of Laboratory and Clinical Medicine 48, 386–391.Google Scholar