Influence of dietary energy and protein on immune response of lambs

An experiment was conducted in lambs divided into two groups, and fed diets supplying 100 (control) or 60 percent of dietary energy and protein requirements. Dietary restriction significantly affected the growth rate during the 180 days of the study. Monitoring of the erythrocytic antioxidant status revealed a significant reduction in the reduced glutathione and glutathione peroxidase levels accompanying an increase in lipid peroxides. The cell-mediated immunity, measured by delayed-type hypersensitivity (DTH) response to phytohaemagglutinin-P (PHA-P), was apparently compromised in the experimental group. However, there was no influence of the diets on the humoral immune response assessed through antibody response to Brucella abortus antigen. It is concluded that the lambs maintained the immunity at the cost of growth performance through possible homoeorrhetic mechanisms.