Further Studies on the Vitamin Requirement of Tapeworms

Abstract

In an earlier paper (1944) we corroborated and extended the work of one of us (Chandler, 1943) showing that Hymenolepis diminuta grows in a normal manner in the absence of any vitamins in the diet of the host except something associated with the G complex, absence of which causes a marked stunting in growth in female but not in male rats. This stunting becomes intensified as the depletion period in the host prior to infection is increased. In the present paper are reported a series of experiments designed to determine, if possible, what factor or factors in the G complex is responsible for the stunting effect. The hosts used were female white rats three to four months old, weighing between 150 and 200 gm at the beginning of the experiments. The rats were infected by oral administration of artificially reared cysticercoids as described in our earlier paper. The complete diet for control animals was the same as described in that paper. The basic vitamin-deficient diet was also the same except that the fat-soluble vitamins were added in the manner previously described, for the benefit of the host animals. The G complex, when used, was provided in the form of 9 gm of autoclaved brewer's yeast per rat per day. Other vitamins or nutritional factors, added in synthetic or concentrated form, were dissolved in 20% alcohol, and the proper amount added to the basic diet each day. Riboflavin (B2), pyridoxine hydrochloride (B6), calcium pantothenate, nicotinic acid, p-aminobenzoic acid, inositol, and choline were used in pure synthetic form and provided at the rate of 100 micrograms per day per rat. Biotin was used in the form of a concentrate containing 20 micrograms per cc, and provided at the rate of 30 micrograms per day per rat. Folic acid was provided in the form of a concentrate at the rate of 90 micrograms per day per rat.