THE EFFECT OF DIETARY ONION AND GARLIC ON HEPATIC LIPID CONCENTRATIONS AND ACTIVITY OF ANTIOXIDATIVE ENZYMES IN CHICKS

Chickens were fed 2% lyophilized onion or garlic with different concentrations of disulfides in diets containing 18% soybean oil for 14 days. Hepatic S levels increased almost two-fold in chicks fed garlic. Hepatic cholesterol concentrations were reduced by garlic but not by onions. Total superoxide dismutase (SOD) activity was decreased by garlic and this was due to reduced activity of the Cu-Zn, SOD. However, in contrast, both onion and garlic increased Mn-SOD activity and hepatic glutathione concentrations. Glutathione peroxidase activity was decreased by garlic. These findings indicate that dietary garlic is more effective as a hypocholesterolemic agent than onion and has additional effects in reducing the activity of antioxidative enzymes. These effects are similar with disulfide intake from onion or garlic.