概日節律是指細胞表現不同時鐘基因，所形成的一種封閉式回饋循環之機制。此機制 使動物在規律的日夜週期下，生理及行為呈現概日的週期性變化。本試驗以15週齡同 源選拔之生長速度快（B 品系）與產蛋數高（L2 品系）的台灣土雞作為材料，採其 腹脂之前脂肪細胞，比較其分化能力與細胞概日節律表現之關聯性。前脂肪細胞經誘 發分化，oil-Red O 脂質染色分析顯示 L2 品系比 B 品系細胞有較多的脂肪堆積，同 時具較高 GPDH 活性。而相對定量聚合酶連鎖反應分析結果顯示，經同期化作用下， L2 品系比B品系細胞有較鮮明的Per2、Bmal1、Cry1、Rev-erbβ、RORβ 約日節律 性振幅。以上結果顯示，以產蛋數選拔之 L2 品系，有較佳的脂肪細胞分化能力與概 日節律表現。至於兩者關聯之機制與兩品系脂肪細胞表現之差異如何影響產蛋仍需進 一步探討。
Circadian clock is known to be resulted an auto-regulatory feedback loop which takes place among circadian gene products and completes a cycle in about one day. This mechanism allows the physiological and behavioral rhythms to synchronize with the typical day-night cycle. This study using adipose stromal-vascular (S-V) cells collected from a fast growing (B) and a high egg production (L2) line of chickens selected from a common base population of Taiwan country chickens to explore the relationship between adipose S-V cell differentiation and circadian rhythms. S-V cells from L2-line displayed higher fat accumulation as evidenced by oil-Red O staining and GPDH activities than those from B-line, when induced to undergo adipocyte differentiation. Amplitudes of circadian rhythm of Per2, Bmal1, Cry1, Rev-erbβ and RORβ mRNA expression measured by RT-PCR analysis in L2-line adipocytes were more significant than those in B-line adipocytes. These results suggest that L2-line adipocytes possessed greater differentiation and higher amplitudes of circadian rhythm than B-line adipocytes. Further studies are required to investigate how these differences in influence egg production.