328 THE BIOCHEMISTRY OF B VITAMINS 



view of this fact, the nutritional requirement is a rather flexible quantity, 

 depending as it does upon the difference between the physiological require- 

 ment and the bacterial synthesis; and it is easy to understand the large 

 number of conflicting reports in the literature on this topic. 



In an extended discussion of human nutrition, it would be appropriate 

 to consider at this point what the actual average consumption of B 

 vitamins was for the many population groups in the world that have 

 been studied in this regard. This formidable task is not here undertaken 

 because the quantity of information is so great, the quality so poor, and 

 the space available so limited. Suffice it to say that for the research 

 statistician a wealth of material lies buried in the literature awaiting 

 analyses from which may come a better understanding of the B vitamins 

 in nutrition. Since the actual consumption of the B vitamins varies among 

 individuals, groups, and geographical areas even more than does the 

 requirement, no simple analysis of this subject is now possible. 



Table 25. Some Reported Requirements of Other Domestic Birds for B Vitamins 

 (mg per 100 gm diet) 



Vitamin and species Amount 



Thiamine 



Pigeon 0.125 



Riboflavin 



Poult 0.3-0.4 



Duck 0.3 



Nicotinic acid 



Poult 5.0 



2-5 mg 

 Pantothenic acid 



Ducklings 1.1 



Vitamin B 6 



Duck 0.25 



Folic acid 



Poult 0.08 



Choline 



Poult 170.0 



Inositol 



Poult 1000.0 



Philosophic Considerations 



In retrospect, the members of the plant kingdom seem able to synthesize 

 the B vitamins while the members of the animal kingdom, as far as we 

 know, have completely lost this ability, except for nicotinic acid. General- 

 izations are always dangerous, but it is remarkable how consistently this 

 one holds true. While parts of plants may be heterotrophic, there is no 

 certainty that small vital cell groups in animal tissue do not have the 

 ability to synthesize B vitamins. Further, whereas certain Thallophytes 

 are heterotrophic and certain protozoa autotrophic, the general nutritional 



