Introduction: Aflatoxin B1 (AFB1) is known as a carcinogenic, teratogenic, mutagenic and growth
inhibitory mycotoxin. Aim: the current study aims to demonstrate the adverse morphological effects of
AB1 on the developing chick embryo. Materials and methods: Fertilized eggs of the chick Gallus domesticus
were divided into five groups: control group, positive control group treated with aflatoxin's solvent (10%
Ethanol), and three experimental groups treated with a single doses of 5ng, 10ng or 20ng of AFB1 extract.
The hatchability and mortality rates were recorded, specimens were weighed, morphologically examined,
and morphometric measurements were carried out for some parameters: Crown rump, head length, head
circumference, head height, fore limb and all parts of hind limb lengths of the embryos after 21 days of
incubation. Results: Current data showed a decrease in hatchability rate (4.76%, 5.48%, 6.9% ) in treated
groups (5ng, 10ng and 20ng) respectively compared to control (97%), weight and all morphometric
parameters were significantly decreased in treated groups compared to control ones and insignificantly
changed among the three treated groups. Mortality rate was increased (13%, 24%, 13%) in treated
groups (5ng, 10ng and 20ng) respectively compared to control (0%). Different congenital malformations
were observed in treated embryos such as: growth retardation, brain deformation, invagination of eyes,
anophthalmia, beak deformities, wry and twisted neck, absence of feathers, open body cavity, limb
deformities such as bud limbs or absence of limbs and poor ossification. Discussion: The present study
demonstrated that AFB1 causes developmental anomalies to the embryo such as decreasing the
hatchability rate, increasing mortality rate and also causes severe congenital anomalies to the embryo,
according to earlier literatures, AFB1 alters DNA and RNA and causes cell death which may explain the
severe malformations during the dvelopment of chick embryo.