Expression of HO and ALAS mRNA in blue- and white-shelled ducks

The native Brown Tsaiya duck (Anas platyrhynchos) is a major laying duck breed in Taiwan, and their eggshell color is varied from white to dark blue. It is possible that the shell gland of blue-shelled ducks (BSD) can accumulate higher concentration of biliverdin than white-shelled ducks (WSD) do. However, there is no strong evidence to prove this assumption. The mRNA expression level of heme oxygenase (HO) and delta-aminolevulinate synthase (ALAS1) of shell gland of BSD and WSD was analyzed in this study. Reverse transcriptase-polymerase chain reaction was performed with total RNA extracted from epithelium cells of shell glands of Tsaiya ducks. The partial cDNA clones of HO1, HO2 and ALAS1 were 258 bp, 263 bp and 111 bp, respectively, and showed an average 91% similarity to chicken sequences. Ultraviolet spectrophotometery and HPLC were used to determine the biliverdin concentration in the serum and uterus liquid at 6, 12, 15, 18, 20, 22 and 23.5 h post oviposition. Real time PCR was applied to analyze these gene expression of liver and shell gland in BSD and WSD. The expression of HO and ALAS1 mRNA of shell glands in BSD and WSD during the ovulation period did not have significantl difference, with exception at 12 h of ALAS1, HO2 in shell gland and HO2 in liver. Results of this study also showed significant differences in the biliverdin concentration in the uterine fluid. Such variations may arise from inconcurrent of mRNA concentration and encoded gene product (enzyme) activity or existence of a mechanism that controls the biliverdin concentration difference of uterine fluid between BSD and WSD.

關鍵字

Blue-shelled duck ； Biliverdin ； Heme oxygenase ； Aminolevulinate synthase

並列摘要

褐色菜鴨為台灣本土主要之產蛋品系，其蛋殼顏色可由白色、淡青色至深青色不等。鴨隻之產出青殼蛋者，其殼腺可能較產出白殼蛋者，累積有更高量之膽綠質，然釐清此等假設之有力試驗證據，迄今尚且付之闕如。本文旨在嘗試藉由殼腺中相關mRNA表現量之論證，以釐清鴨隻殼腺中具有較高活性之血基質氧化酶，對於青殼蛋之形成是否扮演關鍵性角色？應用反轉錄酶－聚合酶鏈鎖反應增殖菜鴨殼線上皮細胞中總RNA，分別得到部分第一型、第二型血基質氧化酶及胺基酮戊酸合成酶cDNA，長度分別為258、263及111bp，與雞者具91%相似度。應用紫外光分光光度計與高壓液相層析儀偵測產青、白殼蛋鴨產蛋後6、12、15、18、20、22及23.5小時之子宮液及血清中膽綠質的濃度。結果顯示，就子宮液中含有之膽綠質濃度而言，鴨隻品系間確實呈現有顯著性之差異（P＜0.05）。相對地，使用即時定量聚合酶鏈鎖反應就殼腺及肝臟中胺基酮戊酸合成酶、第一型及第二型血基質氧化酶mRNA之表現量，在產出青殼與白殼蛋之鴨隻間，彼此亦無顯著性之差異。至於造成產出青殼與白殼蛋之鴨隻間子宮液中膽綠質濃度差異，可能係因mRNA表現量多寡與其嘧定基因產物活性高低間並無直接關聯，抑或存有另一個調控機制所使然。

並列關鍵字

生產青殼蛋鴨隻；膽綠質；血基質氧化酶；胺基酮戊酸合成酶

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