Calorie-protein deficiencies and the immune response of the chicken I. Humoral immunity.

How dependent is the chicken on the calorie (C) and amino acid (AA) levels of the diet? This question was addressed by formulating diets that were two-thirds deficient in C and AA. Feeding the one-third C-one-third AA, one-third C and one-third AA diets for 5 weeks, in general reduced the primary response to 5% sheep red blood cells (SRBC) but not to .5% SRBC. The C/AA deficient birds were returned to a basal diet at 5 weeks and three weeks later reimmunized with SRBC. The secondary response, immunoglobulin G (IgG) titer, of the latter birds after 3 weeks on a basal diet was significantly lower than controls. Total serum protein was significantly depressed during the feeding of one-third AA diet. Transferrin, IgG, and IgM were not affected while albumin was significantly reduced. Gain in body weight was reduced in all groups receiving the C/AA deficient diets. Three weeks after repletion, all groups gained equally.