Nutrition Studies. 57 



hydrates. Scientists still disagree upon the possibility of animal 

 fat being formed thru the decomposition of protein. The prepon- 

 derance of evidence favors such conclusion, as is later shown. (83) 



80. Body fat from food fat. — ^Many experiments have conclu- 

 sively shown that the fat in food, which has been acted on by the 

 digestive fluids in the intestines, may be directly stored in the body 

 tissues when supplied in large quantity. 



Ilofmann^ allowed a dog to starve until its weight had decreased 

 from 26.5 to 16 kilograms and the supply of fat in its body had en- 

 tirely disappeared, as shown by the increased decomposition of the 

 protein tissues at that time. For 5 days this dog was fed large 

 quantities of fat and only a little fat-free meat, during which time 

 it gained 4.2 kgms. in weight. When slaughtered its body con- 

 tained 1353 grams of fat, only 131 of which could possibly have 

 come from the protein fed. Hence much of the fat formed during 

 this time must have come from the fat of the food. 



Henriques and Hansel- fed 2 three-months-old pigs barley meal 

 together with oil. The first pig received linseed and the second 

 cocoanut oil. Samples of the body fat were removed from the back 

 of each pig thru incisions, and analyzed. The fat wdiich had 

 formed during the feeding resembled in odor, consistency, and com- 

 position the vegetable fat which had been fed. Later, when the 

 feeds were reversed with the 2 pigs, the body fat then formed 

 showed a corresponding change in properties. 



All the digested fat taken into the body of the animal beyond 

 that required for maintenance cannot, however, be deposited as 

 body fat, since considerable losses always occur thru the energy ex- 

 pended in digestion and metabolism. Kellner^ states that in the 

 case of carnivora, or flesh-eating animals, such as the dog, not more 

 than 87.3 lbs. of body fat can be formed from 100 lbs. of pure fat 

 supplied in the food. With herbivora, or animals "which consume 

 coarse forage, such as the horse, ox, etc., considerable losses are 

 caused by fermentations which take place in the digestive organs. 

 The work of moving the food thru the digestive tract, digesting it, 

 and disposing of the waste is also relatively large. Hence the 

 amount of body fat which may be formed by these animals from 

 100 lbs. of digestible fat in the food consumed is much lower than 

 with the carnivora, varying from 64.4 lbs. in the case of pure fats 

 to 47.4 lbs. in the fats of roughages. 



^ Ztschr. Biol., 8, 1872, p. 153. ' Ernahr. landw. Nutztiere, 1907, p. 143. 



' Centbl. Agr. Chem., 29, 1900, p. 529. 



