EFFECT OF DEFICIENCY IN ANIMALS 



Biotin deficiency in rats resulted in lesions of the thymus, testes, 

 epididymis, skin and muscles, but there was no degeneration of the 

 spinal cord or sciatic nerves,* Rats required biotin for gestation and 

 for the birth of viable young, and probably for lactation also.^ Indeed 

 the stress of lactation appeared to induce a mild biotin deficiency even 

 without adding avidin or a sulphonamide to the diet.^" The severity 

 and time of onset of symptoms of biotin deficiency were not modified 

 when succinylsulphathiazole was given at the same time as raw egg 

 white, ^ but administration of succinylsulphathiazole alone produced a 

 combined biotin and folic acid deficiency in rats.'' 



Biotin deficiency in mice was characterised by alopecia,^ which 

 was more severe when sulphasuxidine was added to the diet (see 

 page 434). The fur of black mice became rusty or grey.^" Biotin 

 was essential for reproduction and lactation in mice.^^ 



Chicks 



In chicks, dermatitis and perosis were the chief manifestations of 

 biotin deficiency induced by feeding egg white, ^» ^^ and it has been 

 suggested ^° that the development and cure of these symptoms might 

 be used for the biological assay of biotin. Injection of 0-65 fig. per 

 day of crystalline biotin methyl ester prevented the perosis, but was 

 insufficient to prevent the dermatitis. ^^ The typical dermatitis was 

 prevented and growth was promoted in chicks by feeding 7 to 10 jLtg. 

 of biotin per 100 g. of diet.^^ 



Biotin is also said to be necessary for normal embryonic develop- 

 ment in the hen's egg ; ^^ thus when hens were maintained on a biotin- 

 deficient diet the percentage of eggs hatching was reduced by about 

 80 %, although egg production was not affected. 



Biotin deficiency was produced in chicks on a diet of sucrose and 

 acid-washed, alcohol-extracted casein without the administration of 

 egg white. Although dermatitis was regularly produced, the onset of 

 perosis was erratic. The addition of raw egg white produced perosis 

 quickly.^* It was prevented by feeding i fig. of biotin per day, but 

 dermatitis was only cured completely by injection of 2 to 5 fig. per 

 day. A mild biotin deficiency in chicks did not cause neurological 

 lesions, such as were observed in pantothenic acid deficiency. ^^ 



Turkeys 



Turkeys, like chicks, developed dermatitis and perosis when 

 reared on a biotin-deficient diet.^^ The former symptom was cured 

 by biotin, but the latter required, in addition, choline and a factor 

 prepared from yeast extract by adsorption on charcoal or fuller's 

 earth and elution by aqueous ammonia. 



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