維生素e與應(yīng)激反應(yīng)外文翻譯-文庫吧資料
2025-05-21 19:08本頁面
【正文】 k play an extremely important role, immunization hand to protect the body against animal pathogens, on the other hand, as a kind of special stress factor resulting in immunological stress, some damage to the body, the damage is not only affect the growth and development and the production performance of livestock and poultry, and may cause a few animal death. 1,the stress response mechanism The mechanism of stress response is a plex process, according to the Canadian pathologist Hans Selye stress theory, from the stress state of view, can be divided into three periods: alert period (emergency reaction stage), resistance (resistancestage) and failure stage (exhaustion stage). The alert period. The body has not yet received the adaptation period, the body is early response to stressors. According to the physiological and biochemical changes of different, this period can be divided into shock and reverse shock phase. Shock phase as temperature and a decrease in blood pressure, blood concentration, inhibit the nervous system, muscle tension decreased, and then to tissue degradation, hypochloremia, hyperkalemia, gastrointestinal ulceration, body resistance is lower than the normal level. Shock is sustainable for a few minutes to 24 hours. The stress response to enter the shock phase, the defense has been strengthened, increased blood pressure, serum sodium and serum chloride increased, blood potassium reduced, blood glucose increased, catabolism strengthen, atrophy of thymus, spleen and lymph system, eosinophilic leukocytes and lymphocytes decreased, adrenal hypertrophy, improve the total resistance, even higher than that of normal level. In the period of resistance. The body to overe the stress source and get fit, many performance and panic reaction on the contrary, the new supersedes the old. To be normal, assimilation dominant, white blood cells and adrenal cortex hormone content tended to be normal, systemic nonspecific resistance increased to higher than normal level. The failure stage. Performance is like alert period, but the reaction degree increased dramatically, appear all sorts of malnutrition, adrenal cortex although hypertrophy, but cannot produce the necessary hormone, dissimilation again dominated, rapid weight loss, then the reserve depletion, the new supersedes the old. The emergence of irreversible change, to adapt to function damage, leading to death. 2. The clinical symptoms of stress Because the source of stress intensity, duration, chicken breed, age and nutritional status, stress the variety of clinical symptoms, basically divided into the following three types. 2, 1 sudden death of stress syndrome Chicken in the catch, frightened, vaccine reaction or extrusion strong stressor stimulation, not showing any symptoms, sudden death. This is due to strong stimulation, sympathetic adrenal system activity, caused by shock or circulatory collapse and sudden death. 2, 2 acute stress syndrome Mainly due to stress caused by long time strong stimulation, mon are the following: ① heat stress syndrome. The temperature is too high, the hot weather, the crowded transportation, water, chicken body heat too much, difficult heat dissipation, the performance difficulty breathing, mouth breathing, heart rate, body temperature, crown beard flushing cyanosis, muscle tremors, foaming at the mouth, chicken prone to acute bronchial pneumonia and death. ② convulsive stress. Fight, noise, capture, transport, mixing frightened group process, show head feathers ruffled, panic, tension, hide, loss of appetite, and even waste vast, gain weight
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