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

Area of Science:

• Nutritional Science
• Primate Research
• Hematology

Background:

• Folacin (folic acid) is essential for numerous metabolic processes, including DNA synthesis and red blood cell formation.
• Nutritional deficiencies can lead to significant health impairments, particularly in animal models used for biomedical research.
• Squirrel monkeys are a relevant model for studying human nutritional requirements due to physiological similarities.

Purpose of the Study:

• To investigate the effects of acute folacin deficiency on young and older squirrel monkeys.
• To determine the clinical and hematological consequences of varying levels of dietary folic acid.
• To establish the specific folacin requirements for maintaining body weight, growth, and normal hematological parameters in squirrel monkeys.

Main Methods:

• Squirrel monkeys were fed either a deficient diet (no added folic acid) or a control diet with a known folic acid content.
• Older monkeys received diets with varying folic acid levels to observe dose-dependent effects.
• Hematological parameters, physical condition, and biochemical markers (e.g., formiminoglutamic acid excretion) were monitored.
• Repletion studies were conducted using folic acid injections to assess recovery.

Main Results:

• Young monkeys on a deficient diet exhibited rapid weight loss, diarrhea, dehydration, and mortality.
• Older monkeys developed alopecia, dermatitis, and macrocytic anemia with restricted folic acid intake.
• Severe megaloblastic anemia and intramedullary hemolysis occurred in deficient animals, with low folacin levels but normal vitamin B12.
• Folic acid repletion effectively reversed the observed hematological and physical deterioration.

Conclusions:

• Acute folacin deficiency induces severe hematological and physical impairments in squirrel monkeys.
• The estimated folacin requirement for weight maintenance is 28 µg/kg/day, while higher levels (over 75 µg/kg/day) are needed for optimal growth and hematopoiesis.
• These findings highlight the critical role of adequate folic acid intake in primate health and provide essential data for nutritional management in research settings.