FUNCTIONS OF NUTRIENTS 37 



fat, in addition to supplying heat and energy to the 

 animal bodyc 



In practice, however, it is important to economise 

 the more expensive albuminoids as much as possible, 

 by supplying a sufficient quantity of the cheaper carbo- 

 hydrates in the ration for heat, energy, and fat 

 production, thus confining the albuminoids to the 

 repair of waste nitrogenous tissue and the production 

 of lean meat, etc. Kellner states that carbohydrates 

 are quite as effective in preventing protein waste as 

 fat. 



Amides. The amides are soluble in water, and 

 are mostly digestible. A good example of an amide 

 is asparagine, which is made up of the elements 

 carbon, hydrogen, oxygen, and nitrogen. Although 

 asparagine contains nitrogen, it has no power of adding 

 to the nitrogenous tissue when fed to non-ruminants. 

 With ruminants, it does appear in certain cases to 

 have the power of economising the albuminoids. This 

 peculiar power, according to Kellner, is no doubt brought 

 about by the action of bacteria in the alimentary canal, 

 and may be accounted for in two ways : by the bacteria 

 either 



1. Converting in some way or other the amides 



into albuminoids ; or 



2. Attacking by preference the amides in the body, 



and thus destroying a smaller quantity of the 

 albuminoids of food. 



It would therefore appear that ruminants receiving 

 a ration poor in albuminoids but rich in amides may 

 utilise the amides either directly or indirectly to form 

 flesh. 



Further, it appears that amides have no power of 

 forming fat, although when oxidised in the system 



