380 RIBOFLAVIN 



The American cockroach, Periplaneta americana,-^ and Tineola hissel- 

 liellci"^ accumulate much more riboflavin in the malpighian tubes than can 

 be accounted for by the diet. 



D. IN ANIMALS 



M. K. HORWITT 



Riboflavin is essential for growth and normal health for all animals. Its 

 restriction has been studied in nearly all species which are related to hu- 

 man economics. The primary effect of riboflavin restriction is the cessation 

 of growth. Because it is a fundamental constituent of animal tissue, new 

 tissue cannot be formed unless a minimum amount of riboflavin is available. 

 It is therefore necessary not only for growth but also for tissue repair." 

 The amounts of riboflavin needed for normal growth have been discussed 

 in the section on animal requirements. When less than these requirements 

 is provided, a variety of pathological trends become evident. Wolbach and 

 Bessey-^ have published an excellent review of the tissue changes in vita- 

 min deficiencies, in which they summarized most of the studies reported 

 prior to 1942. The large majority of the older papers on the Bo vitamin dealt 

 with mixed deficiencies and often described syndromes which are not seen 

 in modern work with a "pure" deficiency of riboflavin. At present, most 

 of our interpretations of ariboflavinosis in animals are based upon experi- 

 ments which deal with the removal of all, or nearly all, of the riboflavin 

 from the diet. The application to man of such work is limited by the fact 

 that one rarely, if ever, observes a human deficiency syndrome due to the 

 complete absence of dietary riboflavin. More work on the effect of long- 

 standing suboptimal intakes of riboflavin is indicated. 



1. Rats 



Goldberger and Lilly- ^ were apparently the first to describe symptoms of 

 riboflavin deficiency in the rat, as a result of a study in which they at- 

 tempted to produce rat pellagra. They reported a severe ophthalmia and a 

 bilateral, symmetrical alopecia, which almost completely denuded the head, 

 neck, and trunk. The dermatitis which these authors also observed has 

 since been shown to have been complicated by a pyridoxine deficiency.^"- *^ 

 Whereas the lesions of pyridoxine deficiency are characterized by a florid 



25 R. L. Metcalf and R. L. Patton, J. Cellular Comp. Physiol. 19, 373 (1942). 



26 R. G. Busnel and A. Drilhon, Compt. rend. 216, 213 (1943). 



27 M. K. Horwitt, O. W. Hills, C. C. Harvey, E. Liebert, and D. L. Stoinheig, J. 

 Nutrition 39, 357 (1949). 



28 S. B. Wolbach and O. A. Bessey, Physiol. Rci's. 22, 233 (1942). 



29 J. Goldberser and R. D. Lilly, Public Health liepts. (I'.S.) 41, 1025 (1926). 



30 P. Gyorgy, Nature 133, 498 (1933). 



31 P. Gyorgy, Biochcm. J. 29, 741 (1935). 



