ISA Brown hens were fed diets supplemented with the synthetic carotenoids Carophyll Red and Carophyll Yellow at 20 and 15 mg/kg, respectively, lutein at 250 mg/kg, and the algae Chlorella at 12.5 g/kg. The synthetic carotenoids, lutein, and Chlorella significantly increased egg weight (P < 0.001), shell weight (P < 0.001), and thickness (P = 0.017) and decreased the yolk/albumen ratio (P = 0.035) of the eggs. Lutein but not the Carophylls or Chlorella significantly increased the shell breaking strength (P = 0.032). Furthermore, the carotenoids and Chlorella significantly (P < 0.001) increased yolk colour, and the yolk redness increased significantly (P < 0.001) in the following order: control < Chlorella < Carophyll < lutein. Lutein and Chlorella increased the yellowness of the yolks, and boiling the eggs for 5 min increased the redness of the yolks, while boiling them for 10 min increased the lightness and reduced the colour of the yolks. Supplementation of feed with lutein and Chlorella significantly (P < 0.001) increased the concentration of lutein (from 12.8 to 133.9 and 49.0 mg/kg dry matter) and zeaxanthin (from 9.2 to 123.9 and 40.1 mg/kg dry matter) in the yolks, and all carotenoids and Chlorella significantly (P < 0.001) increased the oxidative stability of the lipids of fresh eggs and eggs that had been stored at 18°C for 28 days.  

Marigold flower extract (MFE), a natural source of xanthophylls, was added to the diets of hens at different concentrations (0, 150, 250, and 350 mg/kg of diet) to determine the effects of MFE on hen performance, physical characteristics of egg quality, and carotenoid content of the egg yolk of hens housed in enriched cages. Additionally, the highest dose of MFE (350 mg/kg) was tested under commercial poultry conditions and compared with a feed mixture with added synthetic carotenoids and a control diet without synthetic carotenoids. The highest hen-day egg production (P = 0.005) and egg mass production (P = 0.010) was found in hens fed a diet supplemented with MFE at 150 mg/kg. The performance characteristics, however, were not influenced by MFE under commercial conditions. When the dose of MFE was increased, increased values were observed for DSM Yolk Colour Fan (P < 0.001), redness (P < 0.001), yellowness (P < 0.001), ratio of redness and yellowness (P < 0.001), and decreased for lightness (P = 0.036). In the commercial study, the synthetic carotenoids decreased the value of yellowness (P < 0.001) compared with the control group. The lutein and zeaxanthin content in yolk increased by approximately 11.5 and 5.9 mg/kg dry matter, respectively, after the MFE addition of 350 mg/kg. Supplementation with synthetic carotenoids significantly (P < 0.001) decreased the α-tocopherol content in egg yolk. In conclusion, MFE is a suitable natural alternative for increasing the xanthophyll contents in eggs compared with the commercially used synthetic carotenoids.

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&nbsp;A 2 &times; 3 factorial design experiment was conducted to evaluate the effect of adding lycopene <br />(0 and 75 mg/kg) and vitamin E (0.50 and 100 mg/kg) to the diet of chickens. Moreover, the study investigated growth traits, oxidative stability and chemical composition of leg meat and the vitamin content of meat and liver. The study was conducted using five hundred and forty Ross 308 male broilers that were assigned to one of the six dietary treatments. Significant interactions between lycopene and vitamin E additions affected the body weight of 21-days-old chickens (P = 0.005), the malondialdehyde content in fresh leg meat (P &lt; 0.001) and leg meat stored for 3 days at temperatures of 2.5 to 4&deg;C (P = 0.032), the cholesterol content in leg meat (P &lt; 0.001) and the lycopene content in liver (P = 0.006). The chickens with the highest body weight were fed 75 mg/kg of lycopene and 50 mg/kg of vitamin E. The vitamin E supplement increased the oxidative stability of fresh and stored leg muscle (P &lt; 0.001). The lowest mean cholesterol value (3.49 g/kg of dry matter) was found out in the meat from broilers that were fed 75 mg/kg of lycopene in contrast to broilers fed the control treatment without lycopene (3.93 g/kg of dry matter). Dietary vitamin E significantly reduced the fat content (P = 0.033) and increased the ash content of&nbsp;leg meat. The highest lycopene concentration in liver (2.82 mg/kg of dry matter) was in chickens that were fed the highest levels of vitamin E and lycopene in contrast with the control group (0.28 mg/kg of dry matter). &nbsp;

AbStrAct:The effect of supplementing dietary selenium (Se) and vitamin E was investigated in 330 24-week-old laying hens. The hens were fed a basal diet containing Se and α-tocopherol at 0.11 and 26 mg/kg, respectively, or a diet supplemented with Se at 0.3 mg/kg and vitamin E between 0 and 625 mg/kg. Se was supplied as Se-methionine or sodium selenite. The eggs were collected for analysis during the third, seventh and eleventh weeks of the experiment. Supplementation of either form of Se significantly increased the Se concentration in egg yolks and whites, with a more pronounced effect caused by Se-methionine. The egg yolk α-tocopherol concentration paralleled the dietary α-tocopherol concentration. At a high dietary α-tocopherol concentration (632 mg/kg), the retinol content in egg yolks from hens fed Se-methionine increased significantly. Supplementation of Se-methionine significantly increased the α-tocopherol content in the eggs in the third and seventh weeks of the experiment. A moderate decrease in yolk cholesterol was observed in hens fed Se-methionine and α-tocopherol at 119 mg/kg. The concentration of products from lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) in egg yolks increased marginally during the refrigerated storage of the eggs for 2 weeks. The effect of dietary vitamin E on TBARS formation was generally small, although a more significant effect was observed at the highest dose tested.