Effect of Selection of Japanese Quails for Rapid Growth on Immune Function

This experiment was conducted to study the effect of selection for high four weeks body weight of Japanese quails on antibody titers against inactivated NDV vaccine. A total of 582 birds were used as a base population from which 40 sire families (half sib mating) with ratio 3:1 were selected to be parent for new generation, birds were weighed individually at four weeks of age. Birds of both sex had the highest body weights were selected to be the parents for three successive generations and vaccinated intramuscularly with inactivated NDV vaccine (blood samples were collected at 15, 21 and 28 days post vaccination. Heritability estimates of body weight were 0.48, 0.15 and 0.44 for generation 1, 2 and 3; respectively. Whereas the corresponding values for antibody titers against inactivated NDV were 0.48, 0.80 and 0.46 for generation 1, 2 and 3; respectively, 0.32, 0.21 and 0.08 and 0.45, 0.18 and 0.31; respectively. Significant correlations between body weight and antibody titers were found as -0.8 (21 days), -0.7 (15 days), -0.88 (21 days), for generation 1, 2 and 3; respectively. It was concluded that improving of body weight by genetic selection lowers resistance to Newcastle disease.