Introduction and Summary

immune activity was done in comparison with that of a similar, alcoholic extraction of Calendula officinalis, a plant widespread in Romania, but less studied as an immune stimulant (Della Logia R. et al., 1994). A comparison between the effects of sc injected (0.5 ml/day/bird) alcoholic Calendula officinalis and Echinacea angustifolia extractions in immunologically immature (19 days old) and mature (47 days and 77 weeks old) chickens (n=7 bird/batch) on total leukocyte numbers and phagocytosis, showed that in 47 days old birds the total leukocyte numbers were lower than in 19 days old birds, in all corresponding batches. In young injected birds, both Calendula and Echinacea extractions were inhibiting on total leukocyte numbers, compared to the solvent control. Meanwhile, in older birds, Calendula was indifferent and Echinacea acted in a stimulating way. Following the one week treatment with the extractions and antigen priming, there was an increase of spontaneous phagocytic activity (p<0,001). The Calendula extraction ensured an initial increase and a subsequent plateau of the phagocytosis. Echinacea induced a more intense stimulation than Calendula, but its effects were inhibiting compared to those obtained in control groups. In 19 days old Calendula treated chickens, the most active phagocytosi