Folacin deficiency and requirement in the squirrel monkey (Saimiri sciuresus).

Acute folacin deficiency was studied in eight young squirrel monkeys (Saimiri sciureus). Half of the animals were fed a semipurified deficient diet (no added folic acid) and half were fed a control diet (0.84 mg of added folic acid per kilogram of dry diet). Monkeys fed the deficient diet lost weight and suffered from diarrhea and dehydration leading to the death of one of the animals after 6 weeks. Folacin deficiency also was studied in six older animals fed diets containing varying levels of added folic acid. Monkeys fed diets containing 0.14 or 0.27 mg of added folic acid per kilogram of dry diet slowly developed alopecia, a scaly dermatitis, and a mild macrocytic anemia. When these animals were fed the deficient diet, they lost weight rapidly, the alopecia and dermatitis worsened, excretion of formiminoglutamic acid in the urine increased, and a severe megaloblastic anemia with profound intramedullary hemolysis developed. Deficient monkeys had low plasma and red blood cell folacin values but maintained normal plasma vitamin B12 values. Repletion of the animals fed the deficient diet with injections of folic acid reversed both the hematological and physical deterioration. The folacin requirement for maintenance of body weight in these animals was 28 micrograms of total folacin per kilogram of body weight per day. More than 75 micrograms of total folacin per kilogram of body weight/day may be needed to assure growth and normal hematological parameters and bone marrow cytology.