Immune response kinetics in Nigerian indigenous chickens challenged with attenuated Salmonella
Keywords:Salmonella, immune response, Nigerian indigenous chickens, Animal breeding and genetics
Salmonella infection is a major cause of death in chickens and this disease can be transferred through meat and egg to humans. The use of antibiotics and vaccines in the prevention and control of this infection are not totally efficient and also have their side effects. Therefore, genetic control is a better approach in finding a lasting solution. One hundred and ten chickens (4th generation) comprising the three genotypes of Nigerian indigenous chickens
(NIC) that had shown divergent response (high vs low) to sheep red blood cells antigens were used in this study to investigate the immune response kinetics in NIC after challenged with attenuated Salmonella. There were six classes namely, high titre normal, low titre normal, high titre frizzle, low titre frizzle, high titre naked neck and low titre naked neck. Haematological parameters: packed cell volume (PCV), haemoglobin concentration (Hb),
red blood cells count (RBC), white blood cells count (WBC), heterophils (H), lymphocytes (L), eosinophils (E), basophils (B), monocytes (M) and heterophils-lymphocytes ratio (HLR) were used to assess the immune responses of the chickens and data collected were subjected to General Linear Model procedure of SAS 9.2 version. The results showed that genotypeantibody titre had significant effect (p<0.05) on the immune response parameters but sex had no significant effect (p>0.05), while sex by genotype-antibody titre interaction had significant effect (p<0.05). The immune response kinetics of the chickens after challenge with attenuated Salmonella was shown by the significance of the effect of days of blood collection after challenge. High titre naked neck chickens recorded the highest PCV, Hb and RBC values while genotype-antibody titre had no significant effect (p>0.05) on the rest of the parameters. Low titre naked neck males recorded the highest PCV, HB and RBC values while the rest of the parameters were not significant (p>0.05). Generally, days had significant effect (p<0.05) on all the immune response parameters except on H, L and HLR. The study showed that the high titre naked neck males were least affected by the Salmonella vaccine in terms of decrease in packed cell volume, haemoglobin concentration and red blood cell count while the low titre normal females were most affected.