INFLUENCE OF THERMAL MANIPULATION DURING LATE EMBRYONIC DEVELOPMENT ON PRODUCTIVE PERFORMANCE OF BROILER CHICKS

Abstract

The current study was carried out to evaluate the impact of thermal manipulation (TM) during late-embryogenesis at "13-15" days of incubation on the hatchability parameters, productive performance of broiler chicks, and the acquisition thermotolerance under heat challenge conditions (HC) at the marketing age. The experimental work of the present study was carried out at the hatchery (Pass-Reform, Holland) of Ismailia–Misr Poultry Company and produced chicks were reared at the Poultry Research Station (unit), Faculty of Veterinary Medicine, Cairo University. One thousand and two hundreds fertile eggs were obtained from Cobb-500 breeder stock at 35 weeks of age. Eggs were randomly divided into 4 groups, the first group was designated as control group under normal incubation conditions (C) and the other three groups were designated as thermal treated groups. Normal incubation conditions from day 1 to day 18 of incubation were 37.5°C (99.5 ºF) and 52% relative humidity. At 13-15 days of incubation, the thermal treated groups were exposed to thermal manipulation at 39ºC (102ºF) for 2 (T1), 4 (T2) and 6 (T3) hours.