GROWTH AND FATTENING 87 



fat and only a little fat-free meat, during which time it gained 4.2 kgms. 

 in weight. When slaughtered its body contained 1,353 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 Hansen 22 fed 2 three-months-old pigs barley meal 

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

 nut oil. Samples of the body fat were removed from the back of each 

 pig thru incisions, and analyzed. The fat which had formed during 

 the feeding resembled in odor, consistency, and composition the vege- 

 table fat which had been fed. Later, when the feeds were reversed 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 expended in 

 digestion and metabolism. 



The amount of body fat which can be formed by farm animals from 

 100 Ibs. of digestible fat in the food consumed varies from 64.4 Ibs. in the 

 case of pure fats to 47.4 Ibs. in the fats of roughages. 



127. Fat from carbohydrates. Scientists agree that the fat in the 

 body of animals can be formed from carbohydrates. As early as 1842 

 Liebig maintained that animal fat was formed mainly from the carbo- 

 hydrates, tho it might also originate from the protein of the food. The 

 extensive experiments of Lawes and Gilbert of the Rothamsted Station, 23 

 conducted from 1848-1853 with more than 400 animals, clearly showed 

 that much more fat was stored than could be derived from the fatty 

 matter and protein of the food. 



Soxhlet 24 analyzed the body of one full-grown pig and fed another pig 

 of the same weight a ration of rice and meat extract, both being almost 

 free from fat, for 82 days. The second pig was then killed and its body 

 analyzed. Assuming that the bodies of both pigs were of the same 

 composition when the first was killed, it was found that the second pig 

 stored 22,180 grams of fat in its body during the trial. Only 2,828 

 grams of this could have come from the protein and the fat in the feed, 

 leaving 19,352 grams of fat as the minimum which must have been formed 

 from the carbohydrates in the food. Hence at least 87 per ct. of the fat 

 formed by this pig during the trial was derived from the carbohydrates 

 in the food. 



The formation of fat by ruminants from the carbohydrates was first 

 demonstrated by Kiihn 25 with the aid of a respiration apparatus. Oxen 

 were fed for long periods on meadow hay and starch, which provided 

 a ration low in protein and fat. Even if all the carbon that was con- 



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

 83 Jour. Boy. Agr. Soc., VI, Pt. 1, 1895. 

 "Jahresber. Agr. Chem., 1881, p. 434. 

 "Landw. Vers. Stat., 44, 1894, pp. 1-581. 



