Housing system and nutrition are non-genetic factors that can improve the well-being of animals to obtain higher quality products. A better understanding of how different housing systems and essential oils can influence the performance of layers is very important at the research and commercial levels. The current study aimed to investigate the effects of a housing system and dietary supplementation of rosemary and cinnamon essential oils on layers' performance and egg quality. A factorial arrangement (2 × 3) was performed include two housing systems (floor and cage) and three different types of essential oils (0, 300 mg/kg diet of rosemary and 300 mg/kg diet of cinnamon essential oils) to study their effects on the productive performance, egg quality, immunity, oxidative stress and haematology of ISA brown laying hens during the production stages (from 28 to 76 weeks of age). Birds were randomly divided into two groups each comprising of 1500 birds; the first group was moved from the litter to reared laying cages while the second group was floor reared. Each group was randomly divided into three groups, the first was considered as a control group, the second treated with rosemary essential oil, and the third with cinnamon essential oil. The differences in egg production and weight, egg quality, feed intake and conversion, blood picture and chemistry, immunity, and antioxidant parameters between the different housing systems (floor and cage) were not significant at (p < 0.05 or 0.01). On the other hand, the egg production and weight, Haugh unit, feed intake and conversion, blood cholesterol, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), urea, Ca, P, immunity, and antioxidant parameters were significantly (p < 0.05 or 0.01) better in rosemary and cinnamon groups than in the control group. Furthermore, the results of dietary supplementation with rosemary and cinnamon were very close. Regarding egg production and weight, there were no significant differences due to the interactions. The differences in egg mass among the interactions were also not significant except at 68-76 weeks, where the cage × cinnamon group was the highest. Under the floor rearing system, birds that were fed a diet supplemented with or without essential oils (EOs) consumed more feed than those raised under the cage system. Regarding feed conversion rate (FCR), the differences among the interactions were not significant except at 44-52, 52-60 and 68-76 weeks, where the cage × cinnamon group was the lowest. Excluding glutathione peroxidase (GPx) activity (p < 0.001), all immunity and antioxidant indices were not statistically different as a consequence of the interaction among EOs and housing systems. Additionally, the highest levels of phosphorus were observed for layers fed diets enriched with cinnamon oil with the cage or floor system. In conclusion, the data suggested that supplementation of rosemary and cinnamon essential oils in laying hen diet showed significantly positive effects on hen performance and egg production. Cholesterol, liver and kidney functions, immunity, and antioxidant parameters improved with rosemary and cinnamon supplementation when compared to the control. Additionally, the different housing systems did not result in any positive or negative impact on these traits.
Keywords: ISA brown; antioxidant; essential oils; housing system; immunity; production.