Effects of feeding various levels of Lavandula stoechas essence on quantitative and qualitative characteristics of egg, some blood parameters, and morphological changes of ovary in laying hens

An experiment was conducted to evaluate the effect of Lavander stoechas essence on performance، egg quantity and quality، blood parameters and ovarian morphology of laying hens with one hundred and sixty 30-wk-old Hy-Line (W36) layers with 4 treatments، 5 replicates and 8 birds per each. Treatments included control (without lavander essence)، and levels of 200، 400، and 600ppm lavander essence. Performance parameters including egg weight and egg production were recorded daily and feed intake، feed conversion ratio and egg quality were measured weekly. At the end of experiment، 2 birds of each replicate were slaughtered for blood collection and morphological assessments of ovaries. Level of 200ppm of lavander essence showed a significant increase in products percentage and egg weight. Level of 600 ppm lavander essence showed significant decrease in feed intake. Addition of essence to the diet had no effect on FCR but it caused significant increase in yolk color. In the second period of experiment (28-56 d)، level of 200ppm essence significantly increased properties of egg shell. Blood triglycerides، glucose and HDL were not affected by the treatment، but by adding lavender essence to diet، cholesterol and LDL decreased significantly in compare with control diet. Also، levels of lavander essence had no effect on the relative weight of the ovary، oviduct and stroma. But، levels of 200 and 400 ppm of lavender caused significant increase in number and weight of large yellow follicles. The results showed that the addition of essences of lavender up to 400 ppm improved egg weight and egg shell quality and yolk color. Moreover، the usage of essence increased weight and numbers of large yellow follicles.