Effect of garlic supplementation on complement activity in broiler chickens

Recent studies have demonstrated the potential immuno-modulatory activity of herbal products in human and animals. The present study was performed to elucidate the impact of including fresh garlic powder (FGP) in the diet of broiler chicks on serum alternative pathway of complement activation (APCA) activity, as a functional part of humoral innate immunity. For this, two hundred new-born chicks were divided into three groups: A (50 chicks), B and C (75 each). The chicks in group A were fed control diet, whereas those in groups B and C received diets supplemented with 1% or 3% of FGP, respectively. On day 21, half of the chicks in groups B and C were separated into groups D and E, respectively, and fed control diet afterwards. Sera were collected on days 1, 14, 21, 32 and 42, and assayed for APCA activity. The results showed that APCA activity in groups A and B increased up to day 32 and then decreased (P < 0.05). On day 21, the highest and lowest APCA activities (P < 0.05) were noticed in groups B and C, respectively. On days 32 and 42, group C had the least APCA activity, but the differences among other groups were not significant (P > 0.05). Furthermore, the removal of FGP from the diet led to the improvement of APCA activity in treated groups. In conclusion, garlic supplementation, depending on the rate and period of time used in the diet, may enhance or depress humoral innate immunity in broiler chickens.