When blood plasma proteins are depleted by bleeding, with return of washed red cells (plasmapheresis), it is possible to bring the dog to a steady state of low plasma protein in the circulation and a uniform plasma protein production on a basal diet. These dogs become test subjects by which the potency of various diet factors for plasma protein regeneration can be measured.
Plant and grain proteins are quite well utilized to form new plasma protein in these test dogs but soy bean meal probably should be rated at the head of this list. It is utilized with unexpected promptness and favors the production of albumin in contrast to other plant proteins which distinctly favor globulin production.
Long plasmapheresis periods on basal rations rich in grain proteins lower the resistance of these animals to infection.
Spleen, brain, and stomach when fed with the basal diet in these test dogs show less favorable potency ratios—10.2, 11.8, and 13.6 respectively. This means the grams of tissue protein which must be fed to produce 1 gm. of new plasma protein.
Fasting periods indicate that the dog can contribute only 4 to 6 gm. of plasma protein each week—an insignificant contribution presumably derived from the host's tissue proteins.
Infection and intoxication disturb the plasma protein production of these standardized dogs and may reduce the output of plasma proteins to very low levels in spite of considerable food intake. There may be a very sharp drop in the plasma protein level during the first day of intoxication (Dog 33-324).
Some of these observations may be of value in a study of clinical conditions associated with hypoproteinemia.