Abstract:
This study is aimed at evaluating antibody responses, viral loads, viral clearance and growth rate of
Tanzanian free-range local chicken (FRLC) challenged with LaSota strain of Newcastle disease virus
(NDV) as indicator traits for selection of chickens for breeding with enhanced resistance to the disease
and economic value. Three popular free-range local chicken ecotypes: Kuchi, Ching’wekwe and
Morogoro-medium from three ecological zones of Tanzania were used for the experiments. Progenies
from the breeder chickens were challenged with 10 7 titer of 50% egg infectious dose (EID 50 ) of the virus
at 28 days of age. The viral loads and viral clearance rates evaluated by qRT-PCR from tear samples
collected at 2- and 6-days post infection (dpi) showed that Kuchi could clear NDV better than Morogoro-
medium and Ching’wekwe. Anti-NDV antibody levels determined from blood samples collected at 10 dpi
using ELISA showed that Kuchi ecotype expressed higher mean anti-NDV antibodies compared to
Morogoro-medium and Ching’wekwe. Growth rates determined from body weights collected for 38 days
from day of hatch (D0) to 10 dpi showed higher growth rate for Kuchi than Morogoro-medium and
Ching’wekwe chickens. Kuchi chickens were potentially more resistant to ND compared to Morogoro-
medium and Ching’wekwe.
