2. Materials and methods
2.1. Origin, processing and preparation of propolis
Propolis samples were gathered (Najafabad, Isfahan,
Iran) and frozen (24 1C) immediately. Samples were then
extracted using the method of Yaghoubi et al. (2007) with
some modifications. The frozen samples were broken into
small pieces and extracted with 70% ethanol. The extract
was then shaken at 250 Hz at room temperature for 48 h.
Next, the extract was passed through a Whatman No. 41
filter paper. After approximately 12 h, the extract was
sprayed onto dietary treatments and mixed thoroughly.
Propolis samples were analyzed by gas chromatography–
mass spectrometry (GC–MS) according to Popova et al.
(2004) at the Institute of Organic Chemistry (Centre of
Photochemistry, Sofia, Bulgaria), and the results are shown
in Table 1.