Genetic selection of some immunological traits in local Egyptian chicken strain

Abstract

This work was carried out to investigate the effectiveness of selection for high immune response against Newcastle Disease Virus (NDV) vaccine in local Egyptian chicken strain (Dokki- 4) for two generations. Two lines (selected and control) of Dokki-4 strain were used; in the selected line, chicks were selected according to its immune response against NDV vaccine. In the control line, chicks were randomly chosen. The population families were vaccinated against the common prevalent diseases according to the vaccination programs in the Sakha Animal Production Research Station, Kafr El-Sheikh. Results of selection for high immune response against NDV vaccine showed that; selection was efficient in native Egyptian chicken strain (Dokki-4) for increasing antibody titer levels in the high selected line when compared with the control line (P < 0.05) in two generations. Highly significant differences between generation and line were detected. Sex differences in immune response to NDV vaccine were significant (P < 0.05) for the overall averages a long all generations of selection. Female's titers were higher than those of corresponding males of the same line and generation. Realized response per generation in the selected line was 16.76 and 60.18 for male and 18.54 and 69.50 for female in the first and second generations respectively. This study conducted that the cumulative response for high antibody titers responses against NDV vaccine was 76.94 for male and 88.04 for female after two generations of selection. There were significant differences in livability percentage between high and control lines for antibody response; where high line had higher livability than the control line. The high selected line showed a higher survival rate post challenge, with significant difference (P < 0.05) than the control group in the first week (92.86 % and 86.11 %) and the second weeks (87.69 % and 77.42 %) of observing vaccinated birds. It could be concluded that, genetic selection for high antibody titers against NDV vaccine in Dokki-4 strain improved immune response at different ages under investigation with increasing livability percentages and disease resistance of the birds through two successive generations of selection.