Disease resistance traits of IPB-D2 chickens: Characterization of IgY concentrations, Newcastle disease antibody titers, and leukocyte profiles.

BACKGROUND AND AIM: The IPB-D2 chicken, a potential disease-resistant local Indonesian line, has been developed to improve poultry health and productivity for small-scale farmers. This study aimed to characterize the disease resistance traits of IPB-D2 chickens by analyzing key immunological parameters, including immunoglobulin Y (IgY) concentration, Newcastle disease (ND) antibody titers, and leukocyte profiles. MATERIALS AND METHODS: A total of 100 IPB-D2 chickens were studied. Blood samples from 21-week-old chickens were collected for analysis of IgY concentrations using indirect enzyme-linked immunosorbent assay, ND antibody titers using the hemagglutination inhibition test, and leukocyte profiling using the Giemsa staining method. Correlations between parameters were determined using Pearson's correlation analysis in RStudio. RESULTS: The findings revealed that IPB-D2 chickens exhibited higher IgY concentrations, leukocyte counts, heterophil levels, and monocyte counts compared to their IPB-D1 progenitors. However, ND antibody titers in IPB-D2 chickens were lower than the protective threshold. Significant positive correlations were observed between leukocytes and lymphocytes, and negative correlations were identified between heterophils and lymphocytes. CONCLUSION: IPB-D2 chickens demonstrated a well-balanced immune system with enhanced non-specific (leukocyte and heterophil) and specific (IgY) immune responses. These traits highlight their potential as a disease-resistant poultry line. Future research should focus on molecular selection through transcriptomic analysis to identify candidate genes associated with disease resistance traits, enabling further genetic improvements.