Study On The Damage Mechanism Of The Cold Stress On Chicken's Duodenum

Cold stress was not only a whole-body nonspecific response arised after organism subjected to various internal and external environmental stimuluses, but also an important component of the whole organism's adaptive and protective mechanisms. As a kind of stressors, cold stress could caused a nonspecific changes in the body through changing the stability of internal environment, physiology and behaviors. It was one of the most common stress factors to the animals in cold areas, especially to newborn animals which made it becomes an important factor to restrict the development of animal husbandry in cold areas. There were many reports concerned to prenatal and neonatal rodents exposed in cold stress environment at home and abroad, but few studies focused on domestic animals, poultry were fewer. Intestinal tract, as the body's largest organ contacted with the external environment and unique anatomical features in it's blood vessels, making it more vulnerable to damaged under cold stress circumstance, but it had not been reported about the mechanism of cold stress on intestinal damage although intestinal tract was a important target organ in cold stress. In this study, intestinal tissues were obtained from 1 d chickens, which were preliminaryly used to reveal the damage mechanism of cold stress(12±1℃) on chicken's duonenum through observing the morphology structure of chicken's duodenum in microscope and ultramicroscope, detecting apoptosis, anti-oxidation function(T-AOC, SOD and MDA) and the content of NO free radicals of chickens exposed on the acute(0 h, 1 h, 3 h, 6 h,12 h, 24 h) and chronic (5 d, 10 d, 20 d) cold stress, as well to the detection of express level changes of iNOS, HSP70, Fas and Caspase-3 mRNA. The results shows that:1.It is proved that the cold stress can cause a duodenal hyperemia, hemorrhagic and histopathological changes and cell programmed death in microscope and ultramicroscope levels in chicken, which indicating that cold stress can induce a morphological changes of the duodenum.2.When exposed to cold stress, the contents of MDA and NO in duodenum increase, the activity of NOS and the express levels of iNOS increse, the activities of SOD and T-AOC decrese, which indicating a occurrence of oxidative stress associated with time-effects and a relative to damage degree of intestinal, it is one of the damage mechanisms of cold stress on duodenum.3.Cold stress can increase the expression of Fas, Caspase-3 mRNA in chicken's duodenum so as to induct the cell apoptosis ,which revealed that apoptosis plays an important role in the process of duodenum damage induced by cold stress.4.Cold stress can increase the expression of HSP70 mRNA from chicken's duodenum, indicating that the organism can resist the damage in chicken's duodenum caused by cold stress by this approach.In this study, we preliminarily reveals the damage mechanisms of cold stress on chicken's duodenum and the resistant mechanism of duodenum to cold stress through observing aspects about the changes in morphologic structure of duodenum, oxidative stress, apoptosis and the expression of HSP70 gene. Our aim is to explore methods which can improve animal's cold-resist ability so as to provide a scientific basis and experimental foundation for maintaining animals'normal physiological functions in cold stress environments.