ROLE OF LIGHT AND EARLY HEAT CONDITIONING IN IMPROVING SOME PHYSIOLOGICAL AND IMMUNE RESPONSES IN DUCKS

Abstract

The objective of this study was to investigate the beneficial effects of early age thermal conditioning and lighting regime to reduce adverse effects of hot weather conditions especially on the productive performance, oxidative stress and immune function of Muscovy ducks. A total number of 160 chuckling were used in the study. Ducks were divided into two equal groups. The control group, maintained under normal ambient temperature, the second group were exposed to early age thermal conditioning (exposed to temperature of 39±1°C for 6 h at 5th day of age and then subjected to normal ambient temperature. Each group was further divided into two subgroups at the beginning of the 4 week of age. The first subgroup was subjected to normal day light (16 h light, 8h dark) and the second subgroup was subjected to intermittent light regime of 4h light and 2h dark (make 16h light, 8h dark). Blood samples were collected at 12 weeks of age for assay of some blood parameters. The obtained results could be summarized as follows: Muscovy ducks of both early heat conditioning and intermittent lighting groups had superior improvement in live body weight (LBW), body weight gain (BWG) and feed conversion ratio (FCR) as compared to those of control heated group. Liver, gizzard, heart, edible parts, spleen and thymus percentages were significantly increased in early heat exposed group compared to the control group. Body temperature was significantly decreased by both early- age thermal conditioning and intermittent light regime. Plasma lysozyme concentration of Muscovy ducks was increased in early heat exposed and intermittent light group compared to the control group. Corticosterone level and Hetrophils /lymphocytes ratio decreased in both thermally-conditioned and intermittent light groups compared to control group. Plasma malondialdehyde was significantly decreased in early heat exposed and intermittent light regime group compared to the control group. Superoxide dismutase and catalase enzymes increased in both thermally-conditioned and intermittent light groups compared to control group. It is concluded that a combination of early age thermal conditioning and intermittent light regime reduces oxidative stress and improves the productive performance Muscovy ducklings. Key words: Muscovy ducks. Early heat conditioning, lighting programs blood parameters physiological responses.