Effect of Early-Age Acclimation on Some Physiological, Immunological Responses and Chromosomal Aberrations in Muscovy Ducks During Exposure to Heat Stress

Abstract

Abstract: A total of 150 one day old Muscovy ducklings, were used in the present study to assess the effect of early heat acclimation on some plasma parameters, immune responses and chromosomal aberration during heat stress. Ducks were divided into three equal groups. The control group, was maintained under 32-35°C during the first week, meanwhile, the second and third groups were exposed to high temperature 38°C for 24 h at day 3of age and at day 5 of age, respectively. All the groups were exposed to high temperature (42-43°C) for 4hr for three consecutive days at 9 weeks of age. Chromosomal aberrations were determined at seven days and 9 weeks of age during exposure to heat stress. Early heat acclimation of 3 days had increase in plasma levels of total proteins and uric acid compared to the other groups during exposure to heat stress. While, early heat acclimation caused a significant (P<0.05) reduction in plasma lactate dehydrogenase (LDH) activity as compared to the control group during exposure to heat stress. The relative weights of spleen, thymus and bursa were significantly (P<0.05) higher in early heat acclimated (3 days) group as compared to the other groups during heat stress. There was a significant (P<0.05) improvement in Heterophil / Lymphocyte (H/L) ratio sticking and cell mediated immune (CMI) response to phytohemagglutinin-p (PHA-P) with early heat acclimation. Acclimated ducklings had lower significant(P<0.05) differences in all types of chromosomes aberration compared with the control group during exposure to heat stress at seven days of age but, differences were not significant in