12 



BULLETIN 649, U. S. DEPARTMENT OF AGRICULTURE. 



Considering the diet as a whole, 95 grams of protein, 68 grams of 

 fat, and 150 grams of carbohydrates were eaten per day, of which 

 92.5 per cent of the protein, 95 per cent of the fat, and 97.5 per cent 

 of the carbohydrates were digested. The fuel value of the diet was 

 1,592 calories. The estimated digestibility of grayfish protein and 

 fat as obtained by making allowance for the unutilized protein and 

 fat resulting from the accessory foods of the diet are 92.8 per cent 

 and 94.3 per cent, respectively. 



The four different subjects who assisted in the eight experiments 

 conducted to determine the digestibility of grayfish ate on an average 

 440 grams of grayfish daily as compared with 471 grams of butter- 

 fish, 448 grams of mackerel, and 355 grams of salmon, which would 

 indicate that this fish was eaten with as much relish as the other 



fish studied. 



SALMON. 



Since difficulty was experienced in securing fresh salmon for the 

 purpose of this investigation, a good grade of canned salmon (Chinook 

 salmon, Oncorhynchus tschawytscha) was used instead in the experi- 

 ments here reported. The canned salmon was purchased without 

 regard to any commercial brand from a wholesale grocer, and was 

 taken to represent this type of fish in general use. 



The results obtained in three-day test periods with salmon are 

 given in the table which follows: 



Data of digestion experiments with salmon in a simple mixed diet. 





Weight 

 of food. 



Constituents of foods. 



Experiment, subject, and diet 



Water. 



Protein. 



Fat. 



Carbohy- 

 drates. 



Ash. 



Experiment No. 561, subject H. R. G.: 



Salmon (in form of fish loaf) 



Grams. 



1,004.0 

 411.0 

 297.0 

 514.0 

 23.0 



Grams. 



621.8 



310.3 



20.5 



434.8 



Grams. 



249.8 



10.3 



24.0 



2.1 



Grams. 



108.8 



0.4 



39.8 



2.6 



Grams. 



Grams. 

 23.6 



Potato 



85.9 



210.3 



73.0 



23.0 



4.1 



Crackers 



2.4 



Fruit 



1.5 















Total food consumed 



2, 249. 

 46.0 



1,387.4 



286.2 

 23.3 

 262.9 



151.6 



4.7 



146.9 



392.2 

 13.5 



378.7 



31.6 



Feces 



4.5 



Amount utilized 





27.1 











Per cent utilized 







91.9 



96.9 



96.6 



85.8 











Experiment No. 562, subject A. J. H.: 



Salmon (in form of fish loaf) 



854.0 



528.9 



212. 5 



92.5 





20.1 



Potato 







Crackers 



104.0 

 103.0 

 24.0 



7.2 

 87.2 



8.4 

 0.4 



14.0 

 0.5 



73.6 

 14.6 

 24.0 



0.8 



Fruit 



0.3 

















Total food consumed 



1, 085. 

 42.0 



623.3 



221. 3 



18.3 



203.0 



107.0 

 12.1 

 94.9 



112.2 



6.7 



105.5 



21.2 



Feces 



4.9 



Amount utilized 





16.3 











Per cent utilized 







91.7 



88.7 



94.0 



76.9 











