Abstract
The objective of the present study was to find the effect of cumin seed oil (CSO, Cuminum cyminum L.) on the laying performance, ovarian follicular development and immune response in laying hens under high ambient temperature. A total of 162 Boven hens were randomly divided into three treatments and were fed, ad libitum, diets containing 0 (control), 250 or 500 g CSO per ton from 24 to 30 weeks of age. The experiment was done during summer season where the average temperate was 30 to 36 degrees C. Feed intake and egg mass were recorded. Egg quality characteristics and egg-yolk cholesterol content were evaluated. Ovary and oviduct samples were immediately weighted, and ovarian follicles were classified. Plasma total protein, albumin, total cholesterol, LDL-cholesterol, HDL-cholesterol glutamic oxalacetic transaminase (GOT), and glutamate pyruvate transaminase (GPT) were measured. Yolk width, yolk weight, yolk colour, shell weight and shell thickness were increased by feeding CSO. Egg production rate was not affected. However, dietary 500 g CSO per ton had a significantly positive impact on egg weight in comparison with control. The FCR was improved by feeding 500 g CSO per ton; however, feed intake and egg mass were not affected by CSO treatments. Plasma GOT, GPT and triglycerides were significantly decreased, while, plasma HDL-cholesterol was significantly (p < .05) increased due to CSO treatments. Yolk cholesterol content was significantly decreased; however, liver malondialdehyde (MDA) concentration was insignificantly decreased due to dietary treatments. Interestingly, the inclusion of CSO in laying hens' diets improved the antibody titres against Newcastle disease (ND, p < .05) and against avian influenza H9N1 (p > .05) when compared with the control diet. It could be concluded that dietary inclusion of CSO improved egg weight, FCR, yolk and shell quality characteristics and did not have a negative effect on the reproductive morphology parameters in laying hens.