The effect of environmental temperature on immune response and metabolism of the young chicken. 2. Effect of the immune response to sheep red blood cells on energy metabolism.

We investigated the effect of an immune response, following injection with sheep red blood cells (SRBC) in pullets, on energy balance characteristics and on protein and far gain. Controls were sham-immunized with phosphate buffered saline (PBS). Feed intake, body weight, rate of gain, and metabolizability of gross energy were not significantly (P greater than .10) affected by SRBC-immunization. The magnitude and composition of energy gain were influenced by SRBC-immunization. The SRBC-immunized pullets retained significantly (P less than .01) more energy, deposited significantly (P less than .05) more fat, and had a significantly (P less than .01) lower maintenance requirement of metabolizable energy than PBS-injected pullets during days 1 to 5 after injection. During days 6 to 10 after injection, SRBC-immunized pullets deposited significantly (P less than .05) less fat and significantly (P less than .10) more protein than PBS-injected pullets. Effects of vaccination on metabolic rate and performance characteristics may be comparable with these effects of SRBC-immunization.