86 



MAINTENANCE RATIONS OF FARM ANIMALS. 



the results furnishing also a striking illustration of the interesting relations 

 between protein supply and protein katabolisin which had been demonstrated 

 more than 30 years earlier by the classic experiments of Bischoff and Voit. 



Effect of protein supply on protein TcataboUsm of clog — E. Voit and Korlcunoff. 





Nitrogen in— 



Food. 



Feces and 

 urine. 



Gain ( + ) 

 or loss( — ). 



Nothing 



Grams. 

 



4. 10 

 5.74 

 6.77 

 7. 59 

 8. 20 

 10. 24 

 11.99 

 15. 58 

 13. 68 



Grams. 

 3. 996 



5. 558 

 6.495 

 7.217 

 7.804 

 8. 726 

 10.579 

 12.052 

 14. 314 

 13. 622 



Grams. 

 -3. 996 



-1.458 



- .755 



- .447 



- .214 



- .526 



- .339 



- .062 

 + 1.266 

 + .058 



Extracted meat (grams): 



100 



140 



165 



185 



200 ... 



230 



360 



410 



360 





It is clear that in the protein-fed animal, as in the fasting animal, 

 the demands of the organism for energy take precedence over the 

 need for repair material, and that in default of nonnitrogenous 

 material the protein of feed or of tissue is seized upon and katabo- 

 iized for this purpose even at the expense of a loss of body protein, 

 the body seeming to find it easier to do this than to draw upon the 

 stores of fat in the adipose tissues. 



What is so strikingly true in the total absence of nonnitrogenous 

 nutrients holds good also in less degree in case of their relative de- 

 ficiency. If a portion of the nonnitrogenous nutrients are withdrawn 

 from a mixed ration, the protein katabolism usually increases, while, 

 on the other hand, if nonnitrogenous nutrients be added to such a 

 ration the tendency is to diminish the protein katabolism. This 

 well-known influence of the supply of nonnitrogenous nutrients upon 

 the protein katabolism, even in an abundant ration, is well illustrated 

 by some of Kellner's respiration experiments on cattle, 1 in which 

 starch was added to a basal ration. The following table shows the 

 average daily gain of nitrogen by the animal on the basal ration and 

 the increased gain following the addition of starch. 



Effect of nonnitrogenous nutrients on gain of protein by cattle — Kellner. 



Animal. 



Gain of nitrogen. 



On basal 

 ration. 



With addi- 

 tion of 

 starch. 



Difference. 



OxD 



Grams. 

 12. 75 

 5. 64 

 -.03 



Grams. 

 13.71 

 20.37 

 17. 09 

 12.95 

 15.05 



Grams. 

 + 0.95 

 +20. 73 

 + 17. 12 

 + 5.72 

 + 9.56 



Ox F 



Ox G 



Ox II 



Ox J 



7. 23 

 5. 49 



1 Die Landwirtschaftlichen Versuchs-Stationen, Band 53. 



