Abstract
The current research aims at using canthaxanthin (CAX) and betaine (BET) as nutritional additives in the diets of aged Fayoumi laying hens to improve their persistency for post -peak egg production. A total of 160 Fayoumi hells were randomly distributed into 4 dietary treatment groups from 46-54 wk of age: a group that received a basal diet without supplementations (control), and the other groups received the basal diet supplemented with canthaxanthin at 6 mg/kg (CAX), hetaine at 1 g,/kg (BET) or a combination of canthaxanthin and betaine (MIX), respectively. Parameters of productive performance, egg quality and antioxidant profile were evaluated for all treatment groups. Results indicate that CAX and BET partially improve egg quantity and quality of aged Fayoumi chickens through modulating different pathways of enzymatic and non-enzymatic antioxidant capacity. CAX and BET enhanced the egg numbers produced per hen and improved the feed conversion ratio compared to the control. In addition, CAX increased the total egg mass and the yolk color score, as well as the plasma total antioxidant capacity (TAOC) and glutathione peroxidase enzyme (GSH-Px), while the malondialdehyde (MDA) was decreased in all supplementary groups of CAX and BET. It is concluded that dietary CAX and BET supplementation can support the productive performance of Fayoumi hens at the late phase of egg production through its protective effect against oxidative stress of aging process. This in turn can enhance the complementary role of such local or native chicken breeds to support the commercial sector of egg production especially in the rural areas.