Antioxidant status and growth performance of broiler chickens fed diets containing graded levels of supplementary dihydroquercetin.

Dihydroquercetin (DHQ), also known as taxifolin, is a natural antioxidant that can be commercially obtained by extraction from Siberian Larch (Larix sibirica). Four wheat-soy based diets, formulated to contain 0, 0.5, 1.5 and 4.5 g/kg of supplementary DHQ were prepared. Each diet was fed ad libitum to birds in seven pens (three birds in each pen) in a randomised block design from 7 to 21 days of age. The effect of DHQ on weight gain was not significant overall (P > 0.05), although there was an indication of a linear increase (L < 0.05). The blood glutathione peroxidase responded (P < 0.001) in a curvilinear manner (L < 0.001 and Q < 0.05) to increased dietary DHQ. The results from this study indicate that dietary DHQ supplementation may be beneficial at levels greater than 1.5 g/kg feed, due to improved bird antioxidant status. Further research to define an upper inclusion level and optimal timing for phase feeding programmes is warranted.