Effects od dietary protein, fat and energy on blood hemoglobin and hematocrit in the rat.

Twenty-eight-day old male Sprague-Dawley rats were fed diets containing varying levels of protein, fat and energy for 8 weeks and were killed. Blood hemoglobin and hematocrit measured at the time of killing increased progressively with increases in the level of dietary protein up to 50% protein. The Mean Corpuscular Hemoglobin Concentration (MCHC; hemoglobin concentration in g/100 ml red blood corpuscles) reached a plateau in rats fed diets containing 15% protein or more. Rats consuming low (5%) and high (21.1%) fat diets had lower hemoglobin concentration and hematocrit than rats fed the diets with intermediate fat content (11.9%); the level of dietary fat had no effect on the MCHC. Rats fed restricted amounts of diet had similar hemoglobin concentration to rats fed the same diet ad libitum; however the restricted rats had a lower hematocrit and hence a relative elevation of the MCHC.