HAEMATOLOGICAL RESPONSES OF NIGERIAN LOCALLY ADAPTED CHICKENS WITH DIFFERENT HEAT SHOCK PROTEIN 70 GENOTYPES TO ACUTE HEAT STRESS

Abstract

Heat stress is among the most challenging environmental conditions affecting poultry growth and production, particularly in the tropical regions. Selective breeding of poultry for improved productivity and thermo-tolerance requires a deep understanding of heat-tolerance genes and their association with economic traits. Thus, this study aimed at assessing hematological responses of Nigerian locally adapted chickens with different HSP70 genotypes (AA, AB, BB) to acute heat stress. A total of thirty-six (36) 23-weeks-old FUNAAB Alpha Chicken (FAC) and Yoruba Ecotype Chickens (YEC) with known HSP 70 gene genotype were used for this study. Six chickens per identified HSP70 genotypes (AA, AB, BB) selected from each of FAC and YEC were exposed to heat stress (40±1°C) for one hour. Blood was sampled before and after the exposure. Packed Cell Volume (PCV), Red Blood Cell (RBC), Lymphocytes, heterophil and heterophil/lymphocytes ratio were analysed using standard procedures. Data were analysed using descriptive statistics and ANOVA. After acute heat-stress, the highest PCV value was obtained from birds with genotype BB (32.91±0.26%) while the homozygote AA birds had the least observed value (31.52±0.25). The HSP70 genotype had no significant effects on the RBC, Lymphocytes, heterophil and heterophil/lymphocytes ratio of the studied birds prior to acute heat stress exposure. However, the packed cell volume and haemoglobin values were significantly influenced by the HSP70 genotypes