Evualtion of immunocompetence, growth and carcass quality traits of different broiler crosses of normal and dwarf dams under intensive system

Abstract

Broiler crosses, viz. C1 (PB-l x PB-2), C2 (PB-2 x PB-l), C3 (PB-l x Dwarf), C4 (PB-2 x Dwarf) were produced in a single hatch and the immunocompetence and juvenile performance traits up to 8 weeks were studied to evaluate the performance for these traits. Response to Newcastle disease vaccine (ND), sheep red blood cell response (SRBC), cutaneous basophil hypersensitivity (CBH) response, relative spleen and bursa weights, body weight at 2WK, 4WK, 6WK and 8WK, carcass quality traits like eviscerated weight, giblet weight, fat percentage and dressing percentage were measured at 6 weeks of age. The C4 cross significantly responded to ND vaccine and it was higher than other crosses. The SRBC antibody response in normal dam line crosses (C1 and C2) were significantly higher than the dwarf dam line crosses (C3 and C4). However CBH response did not differ significantly among the 4 broiler crosses studied. Relative spleen weights in C1 and C3 were significantly higher than other 2 crosses. But relative bursa weight in C3 was significantly higher than other 3 crosses. The body weights at 6 weeks of age and body weight gains between 4 to 6 weeks differed significantly among the 4 crosses. Among the 4 crosses C1 ranked first, while, the C4 broiler cross ranked last for 6WK body weight. At 8WK, body weights of nonnal dam line crosses differed significantly from the dwarf dam line crosses. Carcass quality traits, such as giblet weight, eviscerated weight and dressing percentage were significantly better in normal dam line crosses compared to dwarf dam line crosses. Crosses involving dwarf dam line were not at par with normal dam line crosses for body weight traits. It indicated the incompletely recessive nature of the dwarf gene in heterozygous form (Dw+/dw). However, for immunocompetence traits no definite trend was observed between normal and dwarf dam line crosses.