EFFECT OF DEFICIENCY IN ANIMALS 



rate of metabolism of galactose as a result of chronic vitamin B^ 

 deficiency. 



Effect on Infected Animals 



Rats and mice have been used to study the effect of aneurine 

 deficiency on resistance to infection. Mice apparently became more 

 susceptible to Pneumococcus Type I infection when made deficient in 

 aneurine or ribofiavine, and administration of several times the normal 

 intake of either vitamin at the time of infection did not affect the 

 mortality.^^ Similarly, administration of aneurine markedly increased 

 the resistance of mice to respiratory infections by Streptococcus haemo- 

 lyticus.^^ Aneurine-deficient rats and mice were more susceptible to 

 Salmonella typhi murium than were animals fed an adequate diet ; 

 this was a primary result of aneurine deficiency in the mouse, but 

 secondary to inanition in the rat.*^ 



Vitamin Bi-deficient mice showed a lower incidence of infection 

 than normal mice to the murine strain of poliomyelitis virus, though 

 the vitamin Bi-deficient survivors became paralysed after a prolonged 

 incubation period when given adequate aneurine. ^^ A similar increase 

 in resistance to the Lansing strain of poliomyelitis virus was observed 

 when mice were maintained on a vitamin B^-deficient diet, both the 

 mortality rate and incidence of paralysis being lower than in normal 

 animals.*^ Restriction of the caloric intake to 40 % of the normal 

 was, however, equally effective, even when extra aneurine was given 

 so that this striking effect of aneurine on susceptibility to virus infec- 

 tion would appear to be quite illusory. In spite of this the effect of 

 an aneurine antagonist, " oxy thiamine " (see pa^ 127), on polio- 

 myelitis was tested ; it afforded some protection but not as much as 

 that given by a vitamin B^-free diet.^^'^ Vitamin B^ deficiency did not 

 appear to make rats more susceptible to Flexner's MV cotton rat- 

 adapted strain of poliomyelitis virus,** but with the Lansing strain a 

 group of rats receiving an excess of aneurine showed a higher incidence 

 of paralysis than a group of vitamin Bj-deficient animals ; on a second 

 passage, however, there was no difference between the two groups. 



The resistance of aneurine-deficient mice to the Lansing strain of 

 poliomyelitis virus or to Theiler's encephalomyelitis virus was only 

 partly due to the accumulation of pyruvic acid or similar metabolite 

 (see page go), for the addition of pyruvic acid to a diet containing 

 aneurine did increase the resistance of man to these virus infections, 

 but not to the same extent as did aneurine deficiency.*^ Chicks, on 

 the other hand, were protected against avian encephalomyelitis to the 

 greatest degree when given large doses of aneurine throughout life.*® 

 If, however, the chicks were fed on an optimal diet for two weeks, 



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