GROSS MORPHOMETRIC STUDIES ON THE EYEBALL OF THREE NIGERIAN GENOTYPES OF CHICKEN WITH REFERENCE TO SEXUAL DIMORPHISM

Abstract

Thirty apparently healthy adult Normal feathered (NC), naked neck (NN) and frizzle feather (FF) genotypes of Nigeria indigenous chickens (fifteen males and fifteen females all above one year of age) were purchased from local market in Mokwa and slaughtered. The heads were collected for gross morphometric studies. Both right and left eye balls were collected and their gross morphometric measurements were recorded for all the birds. The weight of the eyeball (WOE) was determined by electronic weighing balance. The Medio-lateral circumference of the eyeball (MLC; the circumference of the eyeball along the mediolateral plane; equatorial), Antero-posterior circumference of the eyeball (APC; the circumference of the eyeball, around the median plane from the anterior to the posterior pole; polar), iris diameter (IR), corneal diameter (CD) and sclera diameter (SD) were measured with the help of a digital Vernier caliper. The eye balls data obtained were expressed as mean SD (Standard Deviation) and subjected to Multivariate Analysis of Variance (MANOVA) using SPSS. The results have provided eye ball morphometrics of the chicken genotypes in Nigeria. There was significant difference in eye ball morphometric parameters among the genotypes. The WOE, APC, MLC and SD are significantly (p<0.05) different between the male and the female chicken genotypes. It was observed that males had wider circumferences of eyeball than the females in all genotypes. The results are valuable in clinical comparative avian ocular anatomy and in the assessment of avian ocular pathologies