Nutritional and physiological evaluation of quercetin as a phytogenic feed additive in laying hens

. The objective of the current study was to evaluate the effect of dietary quercetin supplementation on productive and reproductive performance, intestinal bacterial count, and blood biochemical parameters of laying hens. A total of 200 hens at 28 weeks of age were randomly assigned to four treatments (10 hens per treatment, 5 replicates each), group 1 was treated as control (basal diet without any supplementation), group 2, 3 and 4 were fed diets supplemented with 300, 600 and 1200 mg quercetin/kg feed, respectively. Egg production and egg mass increased ( P ≤ 0.001) as a result of dietary sup plementation with 300 and 600 mg quercetin/kg feed, while egg weight and feed intake were not affected, but the feed conversion ratio improved. Shell thickness, Haugh unit and yolk colour score were improved