Supplementation Of The Maternal Diet With Various Carotenoids: Effects On The Antioxidant System Of The Developing Chicks

This experiment was conducted to test the influence of various carotenoids, including canthaxanthin,lycopene and lutein, on egg yolk pigmentation and chicken antioxidant performance in a wheat-based diet.1. Effects of various carotenoids on egg yolk pigmentation and carotenoid compositionA total of 240 Hy-Line Variety Brown were divided into four treatments. They were fed one of 4 different diets for 21d: three diets each contained canthaxanthin (CA) or tomato powder (TP) or marigold extract (MG), and a control diet (wheat based) was low in carotenoid to investigate the effect of different carotenoids on egg yolk color and carotenoid accumulation. The results were as follows:(1) It took 1 week for carotenoid concentrations to be stabilized in Canthaxanthin group and 2 weeks for other treatment groups.(2) The concentration and composition of carotenoids in egg yolk are dependent on diets.(3) The efficiency of transfer of lutein, zeaxanthin and canthaxanthin from the feed to the egg yolk was the highest, reaching about 40%. In contrast, the efficiency ofβ-carotene and lycopene was quite low, about 1~10%.(4) Supplementation of the maternal diet with carotenoids has no significant effect on the concentration of retinol andα-tocopherol in the egg yolk. (P>0.05).(5) The visual colour score appeared to stabilize on day 5 for the control and MG group and on day 7 for the other treatment groups. Indeed, the pigmenting ability of cathaxanthin is the best and the color of yolk is orange, about 14; followed by marigold extract, the visual colour score could reach 8~9; the last is2. Supplementation of the maternal diet with canthaxanthin, tomato powder and marigold extract: effects on the antioxidant system of the developing chickenAt the end of the abovementioned experiment, the eggs of each treatment were collected and placed in an incubator. After hatching, a total of 144 chicks were fed a wheat-based diet for 21d to observe the effect of different carotenoids on the antioxidant system of the developing chicken.(1) Supplementation of the maternal diet with carotenoids has no significant effect on fertility and hatchability (P>0.05).(2) In comparison with the control group, supplementing groups could significantly increase carotenoids concentration of chickens (P<0.01). Notably, the proportion of lutein in the liver of d-old chicks is lower than that of the yolk, but the proportion of canthaxanthin and lycopene in the liver is higher than that of the yolk.(3) After hatching, the concentration of the total carotenoids in the liver decreased markedly, especially in the first week. However, at least in the first 2 weeks the concentration of carotenoids in the experimental groups is significantly higher than that of the control group (P<0.05). The difference is not significant until 3 weeks old. (4) The effect of supplementation of the maternal diet with carotenoids on the concentration of retinol andα-tocopherol in the liver of d-old chickens is not significant (P>0.05). It is interesting that just like carotenoids, the concentration ofα-tocopherol also decreased markedly after hatching, by 15 times at 2 weeks old.(5) In comparison with the control group, the experimental groups can significantly decrease the concentration of MDA and improve the activity of antioxidant enzyme (P<0.05).