Genetic Variations in Haematological Indices of Local and Exotic Turkeys Inoculated with Attenuated Salmonella typhimurium Vaccine

Abstract

Infection due to Salmonella spp is one of the threatening diseases to poultry industry because it can cause economic losses through mortality, morbidity and reduction in egg production. One hundred and sixty poults comprising 80 local and 80 exotic (Nicholas white) were used to examine the variations in haematological response to Salmonella spp in local and exotic turkeys inoculated with attenuated Salmonella spp. Both genotypes were reared separately on deep litter, under the same management practices and wing tagged for proper identification. At 7th week of age, 1ml of blood sample was collected from each turkey into anticoagulant tubes and labeled accordingly for base-line haematological analysis. The turkeys were inoculated at 8th week by subcutaneous injection of attenuated Salmonella vaccine at 0.5ml per turkey. On the 2nd and 7th days after inoculation, 1ml of blood samples was collected from each turkey for haematological analyses. The un-coagulated blood was used to determine packed cell volume (PCV), red blood cell (RBC), white blood cell (WBC) and its differential counts, and haemoglobin (Hb). The mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were calculated. The haematological data collected were analyzed using General Linear Model of SAS 9.0 software. The exotic turkey had higher (p<0.05) values of PCV (38.13±1.01), Hb (12.77±0.33gd/l), MCV (133.39±0.14fL) and MCH (43.35±1.27pg/cell) before inoculation. On 2nd day post inoculation, the local turkey had higher (P<0.05) values of PCV (43.93±1.40%), RBC (3.98±0.12 106µl-1) and Hb (14.56±0.47gd/l). Also, on the seventh day post inoculation, the local turkey had higher (P<0.05) values of PCV (42.13±1.20%), WBC (11.94±0.62 103.µ-1), Hb (14.09±0.38 gd/l) and MCH (40.65±0.34pg/cell). The mean values of PCV, Hb, MCV, MCH and MCHC of local turkeys were higher (p<0.05) on the 7th day than on the 2nd day post inoculation, while the RBC was higher (P<0.05) on the 2nd day post inoculation. The WBC, MCV and MCH values were higher (p<0.05) in exotic turkey on the 2nd day post inoculation. The local turkey showed quick haematological response to Salmonella vaccine especially post inoculation. Therefore, the local turkey could be said to have stronger potential to survive under disease prevailing environment than the exotic turkey.