Department of Animal Breeding and Genetics, Guru Angad Dev Veterinary & Animal Sciences University, Ludhiana, (Punjab).
*Corresponding author: E-mail: Iqbal_bajwa@rediffmail.com
The degree of asymmetry in bilateral traits may reflect genetic and environmental stressors. Weight of legs (thighs and drumstick), wings, shank diameter, length and weight were used to study the bilateral symmetry and evaluate relative asymmetry (RA) in two genetic stocks of broilers. The stocks were a growth selected synthetic stock PB-1 developed at PAU, Ludhiana and a leading commercial stock (C-1), which were raised simultaneously upto the age of five weeks before slaughtering. The cut-up parts yield was found to be significantly higher in stock C-1, while the males exhibited higher yields in both the stocks except for the shank length, weight and diameter where females excelled their male counterparts. The weight of the legs showed directional asymmetry (DA) with right parts consistently being heavier than left while the wings reflected DA in the opposite direction. Shank diameter and length displayed fluctuating asymmetry (FA). Weight of the thighs and the drumsticks demonstrated antisymmetry (AS) in males while DA in females of the two stocks. Stocks differed significantly for bilateral asymmetry of legs, thighs, drumsticks and wings in females only. Overall relative asymmetry (RA) values. Highest values for RA were observed for weight of thighs and wings and lowest for shank weight. Female birds displayed higher RA than males in both the stocks. It may be suggested that an overall higher RA derived for several important traits can be a valid measure of genetic stress in the stocks.
Genetic stress, antisymmetry, bilateral, directional, fluctuating and relative asymmetry
