Fig. 1.

Timeline scheme. The days of age (d) of the birds is indicated by the time line in the upper box. All birds received basal diet between 85 and 100 days of age. From 100 to 128 days of age (Supplementation (S) period), females were provided a diet according to their dietary treatment assignment. Five diets were administrated (10 individuals randomly assigned to each one): two controls (BASAL and VEHICLE) and three increasing doses of thymol (THY2, THY4 and THY6, corresponding to 2, 4 and 6.25 g of THY/kg feed, respectively). Administered diets are indicated with boxes of rounded edges. Vertical dotted lines indicate changes in the diet of each experimental group. Once finished the supplementation period, half of the quail were slaughtered for histological analysis (Slaughter 1). The other half of the quail was subjected to a post-supplementation period of 21 days (pS) during which the basal diet was reestablished. Finished de pS period, the remaining birds were slaughtered for the same purpose as the first group (Slaughter 2). To assess changes in the variables studied, five times of sampling were defined along S and pS periods: one initial sample point; three sample points along the S period and one at the end of the pS period. Thymol concentration in the egg yolk and droppings, fatty acids concentration in the egg yolk and female performance traits were evaluated along the five sample points (horizontal bracket and circles of solid line). Histopathological changes of liver were assessed at the sample point of maximum Sand in the point of pS (horizontal bracket and a circle of dotted line).