DIGESTIBILITY OF SOME ANIMAL FATS. 11 



Summary of digestion experiments with brisket fat in a simple mixed diet. 



Experiment 

 No. 



Subject. 



Protein. 



Fat. 



Carbohy- 

 drates. 



Ash. 



338 



H. F. B 



Per cent. 

 55.6 

 64.6 

 67.5 

 58.9 

 49.0 

 61.4 

 51.5 



Per cent. 

 94.1 

 94.3 

 95.9 

 94.3 

 89.1 

 89.9 

 92.2 



Per cent. 

 96.9 

 96.8 

 96.5 

 97.1 

 94.7 

 96.9 

 9.5.8 



Per cent. 

 47.4 



339 



D. G. G 



60.5 



340 



R.L. S 



O.E.S 



53.3 



341 



50.9 



347 



D. G. G 



45.4 



348 



R. L. S 



57.1 



349 



O. E. S 



51.9 





Average 









58.4 



92.8 



96.4 



52. i 









The data of the experiments indicate that the ration suppHed 82 

 grams of fat daily and that this was 92.8 per cent digested. When 

 allowance is made for the small quantity of fat in the basal ration 

 and for the metabolic products in the corresponding feces, the digest- 

 ibility of brisket fat alone becomes 97.4 per cent. The protein and 

 carbohydrate contained in the diet were 58.4 per cent and 96.4 per 

 cent digested, respectively. 



It is interesting to note that the brisket fat is somewhat more com- 

 pletely assimilated than the kidney fat, of which 93 per cent was 

 digested,^ on an average. Although this difference is not very great, 

 it may contribute added evidence to the theory that the properties 

 of fats vary with the part of the animal body from which the fats 

 are taken. 



I CREAM. 



Owing to the pleasant taste and its very general use in the dietary, 

 the digestibility of milk fat in the form of cream rather than as a 

 separated fat like butter is of particular interest. The question as to 

 whether an emulsion or the separated fat is the more thoroughly 

 digested has been studied by Wells,^ who found in the case of cod- 

 liver oil that very little difference existed in the digestibility of the 

 two forms. In a series of experiments to determine the influence on 

 metabolism of an excess of fat in the diet, Atwater ^ found that an 

 average of 320 grams of fat daily in a simple mixed diet was 98 per 

 cent digested. Approximately 85 per cent of the total quantity of 

 fat eaten was furnished by cream and milk. 



The digestibility of butter, as determined in this office m a series of 

 eight experiments, was found to be 97 per cent,^ and in a later series 

 -of tests, in which the digestibility of the protein of hard palates was 

 studied, butter was found to be 95 per cent digested.^ Due very 

 possibly to the belief that milk fat in all its forms is equally available 

 to the body, very few similar studies of cream have been reported. 



1 U. S. Dept. Agr. BuL 310 (1915). 



2 Brit. Med. Jour., 2 (1902), No. 2181, pp. 1222-1224. 



3 Connecticut Storrs Sta. Rpt. 1901, pp. 230-233. 



4 U. S. Dept. Agr. Bui. 310 (1915), p. 21. 



B U. S. Dept. Agr., Jour. Agr. Research, 6 (1916), No. 17, pp. 041-648. 



