A total of 225 day-old male broiler chicks (Ross-308) were randomly allocated to five treatment groups, with three replicates in a completely randomized design for 42 days. Birds were fed a basal-diet supplemented with: no additive (control-diet), multi-strain probiotic (Lactobacillus acidophilus, Lactobacillus casei, Enterococcus faecium and Bifidobacterium thermophilum), or 0.15, 0.20 and 0.25% ginger (Z. officinale) powder, respectively. The results show no significant differences among treatments for growth traits and carcass characteristics, whereas using probiotics and ginger at all levels resulted in a significant decrease of gizzard weight and abdominal fat compared to the control group. Dietary treatments did not affect blood biochemistry and antibody production against sheep red blood cells (SRBC), IgG and IgM; however, antibody titre was higher in birds fed 0.25% ginger than other diets after 7 days post injection. The Lactobacillus counts in ileal content of birds fed 0.20 and 0.25% ginger were higher compared to the other treatments. In conclusion, dietary supplementation with either ginger or probiotics showed a significant influence on birds' immune response, probably because ginger had strong antioxidant activity and the probiotics stimulated the production of natural antibodies.
Keywords: blood parameters; broiler; growth; immune system; intestinal microflora; medicinal plants.