Effects of olive leaf on blood metabolites and humoral immunity response of broiler chickens

This experiment was conducted to investigate the effects of olive leaf (OL) on immune response and some blood metabolites of broiler chickens. A total of 400 one-day-old broiler chicks (male and female) were randomly assigned to 5 experimental treatments with 4 replicates of 20 birds each. Birds of different treatments were given diets containing 0, 0.25, 0.5, 0.75 and 1% OL powder from 14 to 42 d of age. At 21 and 42 d of the experiment, blood samples were taken from two birds of each pen (8 birds/treatment) to evaluate different blood metabolites. Moreover, in order to determine immunity status, at the end of the experiment, antibodies titer against SRBC and weight of bursa of Fabricious were determined. The results indicated that significant difference was not observed for total Ig and IgM, while IgY was higher in birds fed with 0.75% OL compared to the control group. The heaviest bursa of Fabricious observed in birds fed with 0.25% OL. Feeding with OL resulted in significant reductions in blood levels of triglyceride, cholesterol, glucose, LDL, VLDL, HDL and liver enzymes. In conclusion, the findings show that dietary supplementation with OL had positive effects on blood lipids profile, liver enzymes and immunity of broiler chickens.