Prevention of Immunologic Stress Contributes to the Growth-Permitting Ability of Dietary Antibiotics in Chicks

摘要: The growth-permitting ability of antibiotics fed to broiler chicks was studied as it relates the state activation immune system. In Experiment 1, were two levels (0 or 100 mg streptomycin + penicillin/kg diet) and raised either in an environment with poor sanitation create a chronic stress clean environment. Chicks unsanitary not had significantly lower (P < 0.05) rates weight gain efficiencies feed utilization, higher plasma interleukin-1, compared antibiotics. Adding diet birds did affect any variable. 2, conventional antibiotic tetracycline/kg diet). After 15-d feeding period, half injected Salmonella typhimurium lipopolysaccharide acute immunologic stress. Feeding resulted improved gain, consumption efficiency utilization. Lipopolysaccharide-injected developed heavier livers, spleens intestines relative body weights rectal temperatures hepatic metallothionein concentrations, presumably due Omitting from similar changes. These results indicate that may permit growth by preventing associated metabolic changes brought about monokines including interleukin-1.