Effect of dietary phytochemicals from tomato peels and rosehip meal on the lipid peroxidation of eggs from laying hens.

The aim of the present study was to evaluate the effects of dietary supplementation with tomato peels (TP) and rosehip meal (RM) on their phytochemicals transfer to the egg, the antioxidant profile and the markers of lipid peroxidation in stored eggs. The experiment was conducted on 42-week-old TETRA SL laying hens, which were assigned to three dietary treatments with 30 birds each: the Control group (CON) received a corn-soybean diet containing 6% flaxseed meal without any by-product addition. Groups TP and RM received Diet CON with additionally 2% TP and 2% RM, respectively. Average daily feed intake, feed conversion ratio and laying percentage were not significantly changed by the dietary treatments. Compared to the other groups, the inclusion of dietary TP led to a significant increase in egg weight (p < 0.05) and vitamin E content in eggs (p < 0.05). The dietary inclusion of RM generated a higher vitamin A content in eggs compared to Groups CON and TP (p < 0.10). After 40 d of storage, in Groups CON, TP and RM the vitamin E contents of eggs deceased by 10.1%, 14.2% and 13.3%, respectively, whereas the reduction of the lutein and zeaxanthin concentration in eggs was more pronounced (by 24.8%, 21.8% and 25.5%, respectively). For the most primary as well as for secondary oxidation products, storage time had a significant influence (p < 0.05) on the degradation process of the eggs. After 40 d of storage, the most distinct reduction in the formation rate of secondary oxidation products was observed in Group RM (by more than 30%), while the reduction for Group TP amounted from 15% to 25%, when compared with Group CON. Therefore, the results of the present study showed a significantly positive effect of RM in retarding the lipid peroxidation process during storage.