The energy cost of fat and protein deposition in the rat | British Journal of Nutrition | Cambridge Core (original) (raw)

Abstract
References

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the 'Save PDF' action button.

1. Measurements were made of energy balance by direct calorimetry, and of nitrogen balance in groups of lean and congenitally obese (‘fatty’) Zucker rats at body-weights of 200 and 350 g given a highly digestible semisynthetic diet at 14.0 or 18.4 g/rat per 24 h.

2. Losses of food energy and N in faeces were very small. The fatty rats lost much more N in urine than did lean rats. Despite this the proportion of gross energy that was metabolized was 0.92 for both fatty and lean rats.

3. In all trials, fatty rats lost a smaller proportion of metabolizable energy (ME) as heat and deposited less as protein than thin rats but deposited much more as fat.

4. The amounts of ME required to deposit 1 kJ of protein and 1 kJ of fat respectively were shown by regression analysis to be 2.25 (±0.16) and 1.36 (±0.06) kJ respectively. These values agree extremely closely with recent, more tentative, estimates based on assumptions as to maintenance requirement which the present experiments were able to circumvent. It may be concluded with confidence that the energy costs of depositing 1 g of protein or fat are almost identical at 53 kJ ME/g.

Information

Type

Papers on General Nutrition

References

ARC/MRC Committee (1974). Food and Nutrition Research report of ARC/MRC Committee, p. 30. London: H.M. Stationery Office.Google Scholar

Blaxter, K. L. (1967). The Energy Metabolism of Ruminants. London: Hutchinson Scientific and Technical.Google Scholar

Breirem, K. (1939). Biedermanns Zbl. Tierernähr. 11, 487.Google Scholar

Close, W. H., Verstegen, M. W. A. & Mount, L. E. (1973). Proc. Nutr. Soc. 32, 72A.Google Scholar

Gädeken, D., Oslage, H. J. & Fliegel, H. (1973). Publs Eur. Ass. Anim. Prod. no. 14, p. 169.Google Scholar

Kielanowski, J. (1965). Publs Eur. Ass. Anim. Prod. no. 11, p. 13.Google Scholar

Kielanowski, J. (1976). Publs Eur. Ass. Anim. Prod. no. 15.Google Scholar

Kielanowski, J. & Kotarbinska, M. (1970). Publs Eur. Ass. Anim. Prod. no. 13, p. 145.Google Scholar

Klieber, M. (1961). The Fire of Life. New York: Wiley Ltd.Google Scholar

McCracken, K. J. & Weatherup, S. T. C. (1973). Proc. Nutr. Soc. 32, 66A.Google Scholar

Pullar, J. D. (1969). In International Encyclopedia of Food and Nutrition, Vol. 17. Nutrition of Animals of Agricultural Importance, part 1, p. 471 [Cuthbertson, D. editor]. Oxford: Pergamon Press.Google Scholar

Schiemann, R. (1970). Wiss. Z. Humbolt-Univ. Berl., Mathematisch-naturwissenschaftliche Reihe 19, 35.Google Scholar

Thorbek, G. (1970). Publs Eur. Ass. Anim. Prod. no. 13, p. 129.Google Scholar

Thorbek, G. (1975). Beretn. St. Husdryrbrugs Forsøg., København no. 424.Google Scholar

Webster, A. J. F., Brockway, J. M. & Smith, J. S. (1974). Anim. Prod. 19, 127.Google Scholar