Indian Journal of Poultry Science

Tropical stress causes serious losses in poultry production because it increases mortality and reduces performance of chicken. An experiment was designed to evaluate three indigenously developed broilers viz. CARIBRO-Tropicana (Naked neck and Frizzle gene bearing), CARIBRO-Mritunjai (Naked neck gene bearing) and CARIBRO-Vishal (Normal plumaged) under different THIs (i.e. 72, 85 and 91) exposure for 4 hours daily for 7 days. A total of 324 broiler chicks (i.e. 36 chicks in each group) of 3 weeks of age were used in this study. The changes in hematological ((i.e. Hb, PCV, pH, DLC and H/L ratio) and blood biochemical parameters (i.e. Na, K, Glucose and ACTH) were examined in these experiments at 0^th, 3^rd and 7^th day of each exposure trial. In these exposure trials, glucose and ACTH were observed lowest in frizzle and highest in normal plumaged birds under different THIs. However, Na and K, were observed highest in Frizzle and lowest in normal plumaged birds under different THIs. CARIBRO-Vishal showed highest stress as compared to other genetic groups. Higher the THI exhibited more severe effect on the traits. During the 7 day of exposure trial, birds of all the genetic groups exhibited the phenomenon of acclimatization as reveled by the averages of various traits at different days into the exposure.