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Methotrexate (MTX) analogue of folic acid is an anti-cancerous drug that has been used from many years for treatment of important diseases like rheumatoid arthritis and ectopic pregnancy. This study was performed to evaluate the gross anomalies of chicken embryos after the exposure of MTX on different development stages. A total of 144 eggs were divided into six groups with eight eggs in each group and exposed different dose concentrations viz, control (group 1) 5 µl (Group 2), 10 µl (Group 3), 15 µl (Group 4), 20 µl (Group 5), 25 µl (Group 6). Gross anomalies of chick embryo regarding embryo’s body weight, body length, wings length, hind limbs length, beak length and head diameter were examined on 12th, 15th and 18thdays after incubation. The results of mean values of 12th , 15th and 18th day old chick embryos exposed to 5 µl and 10 µl MTX showed non-significant effect (P>0.05) on embryo’s body weight, body length, wings length, hind limbs length, beak length and head diameter of all groups with respect to control. While MTX with concentration of 15 µl showed significant effect (P<0.05) on the hind limb length of chick embryo. Group 3 individuals (15 µl) were found with removed hairs on the neck area, slow movement of embryo after hatching and poor feeding in chicks. Moreover, among most frequent abnormalities, hind limb lengths, body length and body weight at 15 µl were found reduced in size. Group 4 and group 5 with 20 µl and 25 µl dose concentration respectively caused complete termination of chick embryos.
Keywords: Chick embryo; Embryonic stages; Gross abnormalities; Methotrexate