| 摘要: | 在經濟動物飼糧中，玉米為主要原料。在發霉的玉米中，鐮刀菌屬(Fusarium)的菌株所產生的毒菌是玉米赤黴烯酮 (zearalenone, ZEA)，是一種類雌激素黴菌毒素，容易對動物造成急慢性中毒，引起繁殖性能嚴重的影響。本研究目的是探討雞胚作為玉米赤黴烯酮毒性測試模式的可行性，觀察之受測項目包括性類固醇濃度、孵化率、肝功能、腎功能等。實驗分成5組，分別為控制組、對照組(0)，0.01、0.1、1.0 μg ZEA/egg，於孵化第七天(E7)分別注射到蛋內。於E14、E18、E21天收集胚胎血液(n=8)，分析雌二醇和睪固酮濃度、肝功能、腎功能及利用血球DNA測定性別，另記錄肝與腎之重量。結果顯示，天冬氨酸氨基轉移酶(Aspartate Aminotransferase, AST) 活性在孵化後期有上升，丙氨酸氨基轉移酶(Alanine Aminotransferase, ALT)活性及尿酸(Uric acid, UA)濃度並無變化且其變化也都在正常值範圍內。雌雛血液之雌激素(E2)濃度比雄雛高，而雌轉雄之轉性雛雞之雌激素分泌皆較接近原始性別，表示卵巢功能並未因轉性而受影響。雄雛血液之雄激素(T)濃度比雌雛高，雌轉雄之轉性雛雞之雄性素分泌亦較接近原始性別之水平。肝臟重量分析顯示胚胎14日齡及18日齡之肝和腎重量皆不受ZEA影響，但在孵化日(E21)，較高ZEA劑量組之肝臟較重(P<0.05)，腎臟重量則無明顯差異。總言之，本研究已初步探討與建立雞胚作為毒性試驗之模式。然未來尚須有更精密之劑量設計及更多生理指標之研究以驗證本試驗之初步結論。
Maize is the main foodstuff used in animal diets. Zearalenone (ZEA) is an estrogenic mycotoxin, produced by Fusarium in moldy maize, known to cause acute and chronic toxic effect in animals and exhibit a severe impact on reproductive performance. The purpose of present study is to examine the effect of ZEA on gonadal steroids, hatchability in chicken embryo development, kidney and hepatic function. The fertilized eggs were divided into five groups, including control and vehicle groups. DMSO (0) or ZEA was administered to chicken eggs (n=8) on day 7 of embryogenesis (E7) at doses of 0, 0.01, 0.1 and 1.0μg/egg. Blood was collected from embryos at E14, E18, E21 and analyzed for gender, estradiol, testosterone and blood chemistry. Liver and kidney were also removed and weighted. Results showed that Aspartate Aminotransferase (AST) activity increased at later stage of incubation. Alanine Aminotransferase (ALT) activity and Uric acid (UA) levels were not changed and remained in reasonable range. Plasma estrogen levels found to be higher in female embryo then that in male embryo, and the estrogen level in reversed sex male was similar to the level of its original sex. The testosterone levels in male embryo were in the same manner as estrogen in female and the reverse sex. Liver and kidney weights were not affected by ZEA except at E21, the liver were heavier in embryos treated with higher ZEA doses. In conclusion, a chicken embryo model has been established for the test for ZEA toxicity. However, further research is needed with a more sophisticated doses design and more physiological indicators to strengthen our conclusion. |
