Bursal, intestinal, and spleen weights and antibody response of chicks fed subtherapeutic levels of dietary antibiotics.

Abstract

Experiments were conducted to study the influence of dietary antibiotics on the bursal, intestinal, and spleen weights and antibody responses of broiler chicks. Results indicate a tendency for chicks fed antibiotics to have heavier bursae but significantly reduced intestinal weights. The antibiotics had no effect on spleen weights and antibody response to sheep red blood cells. It was concluded that the beneficial effects of dietary antibiotics for chicks do not appear to be the result of an enhanced immunocompetence and that the use of antibiotics at subtherapeutic levels does not have an adverse effect on the chicks' humoral immune system.