Biotin, B₁, Riboflavin, Nicotinic Acid, B₆ and Pantothenic Acid as Growth Factors for Insects

Abstract

WE have already stated¹ that biotin is very likely a growth factor for the flour beetle Tribolium confusum. Growth of the larva is very much better on a diet consisting of casein, glucose, yeast, cholesterol, salts and water than when yeast is replaced by yeast extract (Table 1, 1). Normal growth is restored by adding the water-insoluble fraction of yeast². All our previously reported experiments indicated that the missing factor in the yeast extract diet was biotin. Since then we have had the opportunity of testing first the most powerful concentrate of biotin then on the market ('Smaco'), and later pure biotin methyl ester ('Smaco'). It was found that both the concentrate (3) and the pure substance (4) improved very strikingly the efficiency of the diet which contained yeast extract instead of yeast.