IV. BIOCHEMICAL SYSTEMS 433 



substance, other than methionine, choline, or cystine, capable of performing 

 in part the same biological functions as methionine.'® 



Unidentified factors in sardine fish meal and yeast were shown to influ- 

 ence the growth response of chicks to methionine by Patton and coworkers 

 in 1946.'^ Some of their data are shown in Table II. These findings showed 

 that a growth response in chicks was produced by the addition of methio- 

 nine to a corn-soybean meal diet. A greater growth response was produced 

 when, instead of methionine, a small amount of fish meal was added to the 

 liasal diet. The amount of methionine in the fish meal corresponded to a 

 quantity which was too small to produce a growth response, for no growth 

 effect was produced by adding an equivalent amount of methionine in the 



TABLE II 



Effect of Methionine and Sardine Fish Meal on Growth of Chicks When 



Added to a Corn-Soybean Meal Diet" 



fomi of \'itamiii-free casein. Furthermore, when fish meal was present in 

 the diet, the addition of methionine did not produce a growth response. 

 These findings indicated that fish meal contained an iniidentified factor 

 which diminished the requirement of chicks for methionine under the ex- 

 perimental conditions encountered. The authors showed that it was pos- 

 sible to prepare a water-soluble fraction from sardine fish meal which was 

 fully effective at a level of 0.06%. They also showed that with purified 

 diets consisting of starch, casein, and gelatin no improvement was produced 

 by fish meal. It is now known that casein often contains \'itamin Bi-., 

 which would account for the lack of a response to fish meal under such 

 conditions. It appears certain that the factor studied in these investigations 



98 H. R. Bird and J. P. Mattingly, Poultry Sci. 24, 29 (1945). 



" A. R. Patton, J. P. Marvel, H. G. Petering, and .J. Waddell, ./. Nutrition 31, 485 

 (1946). 



