EFFECT OF DEFICIENCY IN ANIMALS 



Petering et alJ Chicks were maintained on a purified diet, which 

 resulted in poor growtn, poor feathering, anaemia and high mortality. 

 The symptoms were prevented by yeast or liver extract containing 

 22 to 44 /xg. of vitamin Be, but 4- or 5-pyridoxic acid (page 344) alone 

 did not improve the condition of the birds, and the L. casei factor 

 alone had only a slight effect. The L. casei factor and 4-pyridoxic 

 acid together, however, increased the growth rate and haemoglobin 

 formation, although to a smaller degree than did vitamin Bo. 



Again, when only crude preparations were available, there was a 

 difference of opinion as to whether vitamin Be was the only anti- 

 anaemic factor necessary for chicks. On the one hand, L. C. Norris 

 and G. F. Heuser and their co-workers ^ maintained that it was only 

 effective in presence of a- or ^-pyracin (see page 344) and that a 

 deficiency of vitamin Be or of the L. casei factor caused a macrocytic, 

 normochromic anaemia, whilst lack of j8-pyracin caused a normocytic, 

 hypochromic anaemia. They asserted that less ^-pyracin and L. casei 

 factor were required for growth than for the prevention of anaemia. 

 Hutchings et al.^ on the other hand, foimd that the addition of /S-pyracin 

 to the L. casei factor was not necessary for growth or haemoglobin 

 formation in the chick. Subsequently, when the pure substance 

 became available, they showed ^^ that the effect of synthetic pteroyl- 

 glutamic acid on the feathering of chicks was not enhanced by, inter 

 alia, j^-aminobenzoic acid, ^-pyracin or _/)-aminophenyllactic acid, nor 

 was it modified by the addition of intestinal antiseptics. Some of 

 the inconsistent results obtained were doubtless due to the presence 

 in the diet of variable amounts of vitamin B^g, which was not then 

 known to be a factor essential for haemopoiesis (page 530). 



Folic acid was twice as effective in the chick by injection as by 

 oral administration, 1^ 



Consistent results were obtained with the synthetic factors, 

 and chicks deprived of folic acid for the first four weeks of life re- 

 sponded dramatically to pteroylglutamic acid.^^' ^^ Moreover, mole 

 for mole, pteroylglutamic acid and pteroyltriglutamic acid were 

 utilised equally well by the chick for growth and prevention of anaemia, 

 and the addition of 4-pyridoxic acid lactone had no significant effect 

 on the utilisation of pteroyltriglutamic acid.^* 



The response of chicks to folic acid, however, depended to a con- 

 siderable extent on the diet.^^ The smallest response was obtained 

 with high fat diets or with diets in which glucose, sucrose or starch 

 was the sole carbohydrate, whilst the best response was obtained with 

 diets rich in protein and with a low fat content or with maize meal 

 or dextrin as carbohydrates. Whole liver added to a diet containing 

 sucrose gave a greater response than could be accounted for by the 

 folic acid present. This, of course, suggested the existence of other 



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