Effects of olive leaf extract and vitamin e supplementation in quail diet on some blood parameters and egg yolk fatty acids composition*

Abstract

This experiment was performed to investigate the effect of dietary supplementation with olive leaf extract on some blood parameters and egg yolk fatty acid composition of laying quails. A total of 192 Japanese quail (Coturnix coturnix japonica) 60 d old were allocated to 4 treatment groups with 4 replicates each containing 12 birds. Birds housed in cages and water and feed were given ad libitum during the total period of experiment. 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% P av) that was formulated including vitamins and minerals. Diets were prepared as control (basal diet, group Control), basal diet plus 200 mg α-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, egg yolks samples were analysed; cholesterol levels of groups fed diets with OLE-80 and OLE-120 were significantly higher than the groups fed control diet (p<0.01); vitamin A levels of groups fed diets with vit. E were significantly lower than the groups fed control diet and containing OLE-80 (p<0.05) and vitamin E levels were significantly higher than the other groups (p<0.001). The supplementation of olive leaf extract were influenced to fatty acid composition of egg yolk lipids. The concentration of oleic and linoleic acids in egg yolks were higher in OLE-80 than the others groups (p<0.05). The concentration of PUFA, n-6 fatty acids and n-6/n-3 fatty acids ratio 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 conducted to increase of oleic, linoleic and n-6 fatty acids, and n-6/n-3 fatty acids ratio in egg yolks.