Abstract
The goal of this study was to determine the effect of feeding rosemary and α-tocopheryl acetate on hen performance and egg quality. Ninety-six Lohmann laying hens, 32-week-old, were allocated into four groups. One of the groups was given a control diet (CONT), two groups were given diets supplemented with ground rosemary at 5 and 10g/kg (ROS-5 and ROS-10, respectively), whereas the other group a diet supplemented with 200mg/kg α-tocopheryl acetate (VIT-E). Following 60 days feeding, hen performance and some egg quality characteristics were determined, whereas the oxidative stability of the refrigerated stored eggs and liquid yolks was also examined. Results showed that there were no significant (P>0.05) differences in egg production, feed consumption, feed conversion ratio, egg weight and shape, yolk diameter, height and color, Haugh units, and shell thickness, among the dietary treatments. The extent of lipid oxidation in eggs differed (P<0.05) between the dietary treatments, but did not change with the storage time. In liquid yolks, lipid oxidation was lower (P<0.05) in the ROS-5 group compared to the CONT group. The ROS-10 group, in turn, exhibited lower (P<0.05) oxidation rate than the ROS-5 group, a finding suggesting that rosemary exerted a dose dependent antioxidative activity. The VIT-E group presented lower (P<0.05) lipid oxidation rate compared to all other groups.
