Effect of Dietary Supplementation of Olive Leaves and/or α-Tocopheryl Acetate on Performance and Egg Quality of Laying Japanese Quail (Coturnix japonica)

Nowadays, there is an increasing interest in the identification of natural substances that can increase animal production. In this experiment performance parameters and egg quality of laying Japanese quail dietary supplemented with olive leaves and/or alpha-tocopheryl acetate were studied. For this reason 108 Coturnix japonica quail (72 females and 36 males), 149 days old, were divided into four groups with three replicates of 9 birds each (6 females and 3 males). One group was given a basal commercial diet and served as control. The diets given to the other three groups were also based on the commercial diet with the addition of dried olive leaves powder at 10 g kg(-1) or at 20 g kg(-1) or alpha-tocopheryl acetate at 300 mg kg(-1). The quail were kept for 29 days under commercial conditions. Egg production, feed consumption and mortality were calculated. Also, egg weight, egg yolk, albumen and shell percentages, egg yolk colour (L*a*b* colour space), blood serum total cholesterol and blood serum triglycerides were determined at the end of the experiment. The dietary addition of olive leaves increased the egg production (p <= 0.001), affected the egg yolk colour (p <= 0.05) and modified the blood serum total cholesterol (p <= 0.01). Moreover, regression analysis showed that the dietary addition of olive leaves had a linear effect on egg production, egg yolk colour and blood serum triglycerides. The dietary addition of alpha-tocopheryl acetate affected (p <= 0.05) the egg yolk colour. In conclusion, dietary olive leaves could be used in Japanese quail nutrition without any adverse effect on their performance and egg quality.