The effects of supplemental olive leaf extract in diet on performance and some blood parameters of quails.

This experiment was performed to investigate the effect of dietary supplementation with olive leaf extract on performance and some blood parameters of laying quails. A total of 192 Japanese quail (Coturnix coturnix japonica) 60 d old were allocated to 4 treatment groups with 4 replicates containing 12 quail each. Birds were maintained in laying cages and received water and diet ad libitum during the total period of experiment. A 16:8 hours light:dark photoperiod was employed. The experiment lasted for 42 days. At the end of experiment, 6 birds were slaughtered for blood samples.The quails received a basal diet (maize and soyabean meal based;19.1% CP, 2.940 kcal/kg ME, 3.0% Ca and 0.39% aP) that was formulated including vitamins and minerals. Diets were prepared as control (basal diet, group K), basal diet plus 200 mg ?-tocopherol acetat/kg (group E), and basal diet plus 80 or 120 ppm Oleuropein (OLE) (group OLE-80 and OLE-120).At the end of the experiment, olive leaf extract supplementation in diets did not have significant effects on final body weight, daily weight gain, average daily feed intake and feed conversion ratio (FCR) (P>0.05). The averages of egg weight were determined to be 11.36, 11.62, 11.44 and 11.28 g and egg production rate were determined to be 53.83, 55.95, 54.61 and 45.25 % in Control, GroupE, OLE-80 and OLE-120 groups, respectively. The lower egg weight (P<0.01) and egg production (P<0.001) were found in OLE-120. The mortality rate were not affected (P>0.05) by the treatments. There were no differences between in terms of blood glucose, triglyceride, HDL cholesterol, LDL cholesterol and VLDL cholesterol levels (P> 0.05).At the end of the experiments, egg yolks samples were analysed; cholesterol levels were determined to be 10.43, 12.07, 13.10 ve 12.28 mg/g (P<0.01); vitamin A levels 0.11, 0.06, 0.13 ve 0.10 mg/g (P<0.05) and vitamin E levels 0.95, 3.32, 1.13 ve 1.32 mg/g in Control, GroupE, OLE-80 and OLE-120 groups, respectively (P<0.001). Olive leaf extract supplementation had no significant effects on vitamin D2 and D3 (P> 0.05). A maximum level of stigmasterol were detected in OLE-120 (P<0.05). The supplementation of olive leaf extract were affected to fatty acid composition of egg yolk lipids. The concentration oleic (7.28 ? g/g) and linoleic (3.76 ? g/g) fatty asids in egg yolks were higher in OLE-80 than the others groups (P<0.05). The concentration of PUFA (6.19 ? g/g), n-6 (4.36 ? g/g) fatty acids and n-6/n-3 fatty acids ratio (2.48) were the highest in OLE-80 groups than the other groups.These results showed that the supplementation of 80 ppm OLE in quail diets was concluded to increase on oleic (C18:1n9), linoleic (C18:2n6c) and n-6 fatty acids, n-6/n-3 fatty acids ratio in egg yolks, without effect the production performance.