FREQUENCY OF DIFFERENT CONGENITAL ANOMALIES IN PRENATALLY VALPROIC ACID TREATED CHICK EMBRYOS

Congenital Anomalies in (VA) Treated Chick Embryos

Abstract

Objective: To determine the frequency of different congenital anomalies in surviving chick embryo on hatching after the prenatal administration of valproic acid by comparing with age-matched controls.
Study Design: Experimental study.
Place and Duration of Study: Anatomy Department, College of Physicians & Surgeons Pakistan (CPSP) Regional Centre, Islamabad, from February 2010 to February 2011.
Material and Methods: Thirty fertilized chicken eggs were injected with valproic acid, incubated and then evaluated for different gross congenital anomalies, on hatching or day 22 of incubation whichever was earlier. Chicks of this group were labeled as experimental group-A. Similarly, another group of thirty fertilized chicken eggs labeled as control group-B, underwent sham treatment using normal saline. The weight and length of alive chicks, the total number of chicks with gross anomalies and the number of different types of gross anomalies in both groups were noted and statistically compared.
Results: In control group-B, 28 chicks hatch out on 21 day of hatching with no visible gross deformities. Whereas in experimental group-A, 23 chicks were alive, out of which, 9 chicks were with delayed hatching on 22 days of hatching. The chicks with gross deformities were 8 (p=0.0008) which included: limb abnormalities (i.e. inverted feet) in 6 chicks (p=0.006), eye abnormality (i.e. closed palpebral fissure of both eyes) in 2 chick (p=0.2), 1 chick showed multiple deformities including gastroschisis, closed palpebral fissures and inverted foot (p=0.45). There were behavioral changes in 10 chicks (p=0.0001). There was statistically significant difference in their weights (p=0.03).
Conclusion: Prenatal exposure of chick embryos to valproic acid increased the incidence of different gross deformities.