Huff G R, Huff W E, Balog J M, Rath N C
USDA Agricultural Research Service, Poultry Production and Product Safety Research, Poultry Science Center, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 1999 Jan;78(1):38-44. doi: 10.1093/ps/78.1.38.
Five-week-old male and female commercial turkeys were immunosuppressed with two levels of dexamethasone (DEX) and challenged by airsac inoculation with 100 cfu of Escherichia coli. Mortality and airsacculitis (AS) scores were significantly higher in challenged birds treated with DEX and marginally higher in males than in females. Male mortalities had significantly higher AS scores than females. Recovery of E. coli from blood and tissues was significantly higher in challenged birds treated with DEX, marginally higher in males (P = 0.09), and significantly higher in male mortalities than in female mortalities. The low level of DEX seemed to have a protective effect against bacterial challenge in males, whereas the high level of DEX had a more adverse effect in males than in females. Body weights 2 wk postchallenge were significantly decreased by both DEX and E. coli, challenge. Relative liver and heart weights were increased by both DEX and E. coli, challenge, whereas bursal:spleen ratios were decreased by both treatments. Total leukocyte counts and relative heterophil counts from blood samples taken 24 h postinfection were significantly higher in DEX-treated birds and in unchallenged DEX-treated females than in males. The DEX treatment resulted in significantly higher heterophil:lymphocyte ratios, but there was no difference between sexes. Males had significantly lower serum levels of uric acid, total protein, albumin, aspartate aminotransferase, and lactate dehydrogenase than did females. Dexamethasone treatment also resulted in lower levels of total protein, albumin, and aspartate aminotransferase. These data suggest that male turkeys may be more susceptible to colisepticemia than female turkeys, especially when under severe stress.
5周龄的雄性和雌性商品火鸡用两种剂量的地塞米松（DEX）进行免疫抑制，然后通过气囊接种100 cfu大肠杆菌进行攻毒。接受DEX治疗的攻毒火鸡的死亡率和气囊炎（AS）评分显著更高，雄性的AS评分略高于雌性。雄性死亡率的AS评分显著高于雌性。接受DEX治疗的攻毒火鸡从血液和组织中回收的大肠杆菌数量显著更高，雄性略高（P = 0.09），雄性死亡率中的回收量显著高于雌性死亡率。低剂量的DEX似乎对雄性抵抗细菌攻毒有保护作用，而高剂量的DEX对雄性的不利影响比对雌性更大。攻毒后2周，DEX和大肠杆菌攻毒均使体重显著下降。DEX和大肠杆菌攻毒均使肝脏和心脏相对重量增加，而两种处理均使法氏囊：脾脏比值下降。感染后24小时采集的血样中，接受DEX治疗的火鸡以及未攻毒的接受DEX治疗的雌性火鸡的总白细胞计数和相对嗜异性粒细胞计数显著高于雄性。DEX处理导致嗜异性粒细胞：淋巴细胞比值显著更高，但两性之间没有差异。雄性的血清尿酸、总蛋白、白蛋白、天冬氨酸转氨酶和乳酸脱氢酶水平显著低于雌性。地塞米松治疗还导致总蛋白、白蛋白和天冬氨酸转氨酶水平降低。这些数据表明，雄性火鸡可能比雌性火鸡更容易患大肠杆菌败血症，尤其是在受到严重应激时。
