本試驗旨在討論紅羽土雞孵化期間於不同時間窗調整孵化溫度及濕度對其性別分化基因與胚胎尿囊液中的雌酮(estrone)之影響。分400顆及300顆種蛋兩批入孵，每批平均分為5組；控制組全程以正常溫溼度(100˚Ｆ/RH:58％，第19日改為98 ˚Ｆ/RH:60％）孵化；試驗組則分別於孵化0~2日(E0-2)、1~3日(E1-3)、2~4日(E2-4)、3~5日(E3-5)調整溫濕度(102˚Ｆ/RH:54％)。於孵化後計算孵化率，並判斷雛雞之基因型性別與表現型性別。以計算其轉性率。第一批於胚胎發育期間分析DMRT1基因之表現。第二批於胚胎發育期間分析尿囊液中的荷爾蒙濃度。結果顯示，轉性率方面僅E35有較高的母轉公轉性率(10%)。無關調溫之時間窗，DMRT1於E3開始表現，E4以後迅速下降，尤其以雄胚為明顯。E6-E7已完全偵測不到其表現。雌禽雖在E3-E5亦有表現，但表現量遠低於雄性。雌性胚胎之estrone於第八日齡開始檢測出，且濃度隨胚胎的發育期越來越高，而雄性胚胎亦於八日齡左右檢測出，但其濃度和雌性胚胎相差甚遠。綜言之，紅羽土雞於孵化第3~5日調整孵化溫度及濕度，可以有較佳的雄性率及孵化率，而DMRT1基因表現與第3日快速表現後即迅速下降，證實胚胎孵化前期調整孵化溫度是對於性別分化有一定的影響。
The purpose of this study was to optimize the condition for incubation in order to obtain higher male ratio of the red feathered Taiwan Country chickens. 400 and 300 Fertilized eggs (Exp1:400, Exp2:300) were divided into five groups with different time window for thermal manipulation (TM): Control, E0-2, E1-3, E2-4 and E3-5. The normal incubation condition was 100˚Ｆ/RH:58％ (E0-E19) and then adjusted to 98 ˚Ｆ/RH:60％ (E19-E21). Incubation condition was changed to 102˚Ｆ/RH:54％ during the TM time window. Embryos at all time point were analyzed for sex reversal, DMRT1 gene expression and estrone concentration. Results showed that the TM at the E3-5 time window provides the best sex reversal rate. Regardless of TM time window, DMRT gene expression in male embryos started and reached a peak at E3 then soon begins to drop after E4 and last until E6. Same observation was found in female embryos except that the expression was much weaker than the males. Estrone level in allantoic fluid of female embryos can be detected since E8, then increased gradually afterworth. Although same trend can be observed in male embryos, but the concentration of estrone was much lower. In conclusion, DMRT expression at E3 is essential for male differentiation of red feathered Taiwan Country Chicken and the best timing for thermal manipulation is from E3 to E5.
