Document Type : Original Article
Authors
1
Iran, Mashhad ,Ghasem Abad , Ostad Yosefi Street. Department Of Animal Science. Postcode: 9187147578
2
Ran, Mashhad ,Ghasem Abad , Ostad Yosefi Street. Department Of Animal Science. Postcode: 9187147578
3
Department of Agricultural Science, Ma. C., Islamic Azad University, Mashhad, Iran
Abstract
The use of natural feed additives as alternatives to antibiotics in poultry nutrition has gained increasing attention. Marigold (Calendula officinalis) is rich in bioactive compounds such as carotenoids, flavonoids, and saponins, which can influence the performance and immunity of birds. This study was conducted to investigate the effects of different levels of marigold oil extract on productive performance, immune response, and egg quality in laying hens. A total of 80 laying hens (Hy-Line, 34 week) were randomly assigned to a completely randomized design with 5 treatments, 4 replicates, and 4 birds per replicate, over an 8-week period. The treatments included: 1) basal diet + 0.2% extract, 2) basal diet + 0.4% extract, 3) basal diet + 0.8% extract, 4) basal diet + commercial pigment, and 5) a control diet (corn-soybean). Performance parameters, egg quality traits (yolk color, yolk weight, shell thickness, Haugh unit), and antibody titers against SRBC were measured. The results showed that treatments containing the extract, particularly at 0.4% and 0.8% levels, significantly improved egg weight, egg mass, and feed conversion ratio compared to the control (P
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