Evaluation of the hematological and clinical biochemical markers of stress in broiler chickens

BACKGROUND AND AIM: Stress significantly affects health and productivity of animals. There is need for affordable and easy-to-assay markers of physiological stress in broilers. This study evaluated hematological and serum biochemical markers of physiologic stress in broiler chickens. MATERIALS AND METHODS: Thirty day-old broiler chickens were assigned to three groups of ten broilers each during the 56-day study. Group 1 broilers served as the control and were not exposed to any stressors; Group 2 broilers were stocked at the stress density of 50 kg BW m(–2) from day 49 to 56 while Group 3 broilers had their feed withdrawn 36 h before blood collection on day 56. Blood samples were collected on day 49 (pre-stress sample) and day 56 (post-stress sample) from all the birds and subjected to hematological and serum biochemical analysis. RESULTS: The parameters did not vary significantly (p>0.05) pre-stress. Post-stress, there were significant variations in the heterophil, lymphocyte, and eosinophil counts and in the heterophil to lymphocyte ratio across the three groups. The concentrations of the plasma fibrinogen and serum albumins, sodium, and sodium to potassium ratio of the broilers varied significantly across the groups. CONCLUSION: Heterophil, eosinophil, and lymphocyte counts, the heterophil to lymphocyte ratio, plasma fibrinogen, serum albumin, sodium, and sodium to potassium ratio are significant markers of physiological stress in broilers.