Use of sulfasuxidine, streptothricin, and streptomycin in nutritional studies with the chick.

Sulfonamides are known to alter the intestinal flora of animals, with a consequent change in the synthesis of certain vitamins by the intestinal bacteria (l-5). This altered synthesis may in turn lead to an increased dietary vitamin requirement for some animals or invoke new requirements in others. For example, the inclusion of 1 per cent of sulfasuxidine in the diet of chicks increases their folic acid requirement about 3-fold (6). The question then naturally arises whether other bactericidal or bacteriostatic agents could produce still different changes in the intestinal flora and lead to increased requirements for other vitamins or to new types of deficiencies. Further, a reverse phenomenon could possibly be encountered; namely, the inhibition of certain bacterial groups which might decrease the growth of th? animal either through the consumption and consequent immobilization of vitamins or through the production of toxic compounds. Finally, a drug or combination of drugs that would completely inactivate all bacteria in the intestinal tract would be highly desirable, since investigators would be provided with an essentially sterile animal and vitamin requirements could be studied uncomplicated by “intestinal vitamins” or toxic substances. This investigation was carried out with the latter view in mind.