STIMULATION OF ADRENALS DURING THE CRITICAL PERIODS OF DEVELOPMENT AND PRODUCTION IN FOWLS

The functional reserves of the organism realized through influence on the adaptation systems during the critical periods of development could be important in improving the adaptability of poultry to intensive conditions. The efficiency of such an approach was considered taking the investigations of the hypothalamo-hypophysial-adrenal system (HHAS) in hens as an example. Seven periods were distinguished in the development of the HHAS, including 2 critical ones: from 13th-19th day of embryogenesis and the 3rd wk of postembryonic development. These 2 periods were associated with the regulatory reorganization of interactions between the components of the system. The exposure of the organism to repeated cooling during the critical periods resulted in a steady rise of HHAS activity and, simultaneously, in higher viability of embryos and chicks. A new regime for cooling eggs of broiler crosses during incubation was outlined based on the result of low temperature stress imprinting, which stimulated broiler development.