Protein deficiency and energy restriction in young cebus monkeys

Infant cebus monkeys (Cebus albifrons) were fed liquid formulas that were limited in protein, energy, or a combination of the two restrictions. Weight gain, food intake, hematological development, and plasma protein and cholesterol levels were monitored over a 20-week period. The animals restricted in protein developed the classical signs of protein deficiency--reductions in plasma albumin, a mild anemia, accumulation of fat in the liver, and, in a few cases, facial edema. These animals maintained a relatively high energy intake, and apparently wasted energy when compared to similarly non-growing energy-restricted animals. Energy-restricted animals did not exhibit these symptoms, even when their daily protein intake was reduced to match that of protein-restricted monkeys. It is concluded that an energy restriction superimposed upon a limited protein intake did not increase protein requirements or precipitate protein deficiency.