Effects of Thymus Powder (Thymus Vulgaris L.) on Egg Quality and Some Ovarian Parameters in Laying Hens

An experiment was conducted in order to investigate the effect of different levels of Thymus vulgaris powder (0, 1, 2, and 3%) on performance, egg quality, some ovarian parameters, and level of malondialdehyde in the liver and follicular fluid of Hy-Line w36 laying hens. The hens were divided into 4 equal treatment groups and each treatment consisted of 4 replicates in a completely randomized design. In the period of 26 to 33 weeks of age, no significant difference was observed among the dietary treatments in terms of egg production, shell-less egg ratio, feed intake, and feed conversion ratio; but egg weight and egg mass were affected by 2% thymus powder  (P<0.05). In the period of 34 to 39 weeks of age, shell-less eggs (%), egg production (%), and feed efficiency were not affected by thymus powder, but feed intake, egg mass, and egg weight were significantly affected by treatment 3 (P<0.05). The egg quality characteristics were measured at the end of weeks 26, 30, 34, and 38 of age. The results showed that only in week 26, the Haugh unit was significantly increased by 1 and 2% thymus powder (P<0.05). At the end of the experiment, the number of white, large yellow, and small yellow follicles, and level of malondialdehyde in the liver and follicular fluid were recorded and none of these were not affected by different levels of thymus powder. Overall, the experimental results showed that the use of 2% thyme powder in the laying hen diet improved the egg mass and egg weight, and also increased the Haugh unit during the peak production period.