脂質代謝物對乳牛週邊白血球免疫調節與產後疾病發生率之影響

報告時間：2024-06-21
報告地點：407視聽教室
指導老師：王建鎧、陳鵬文
學生：李政諺
摘要

 牛隻的轉換期通常被定義為分娩前後三週。在此期間，牛隻經歷分娩和泌乳等生理變化且能量需求增加，將導致負能量平衡 (negative energy balance, NEB)。此時，牛隻會進行脂肪動員，產生非酯化脂肪酸 (non-esterified fatty acids, NEFA)以滿足額外的能量需求，並產生代謝β-羥基丁酸 (β–hydroxybutyric acid, BHBA)，因此NEFA和BHBA被視為良好的NEB指標。乾物質攝取量顯著減少和採食量回升延遲將加劇負能量平衡，而過度的NEB進一步導致泌乳量減少、增加產後疾病發生率及淘汰率。因此，本研究的目的是探討脂肪代謝對牛隻健康的影響與可能原因。首先，轉換期間脂肪代謝物物濃度增加，導致亞臨床子宮內膜炎（風險比增加25倍）和膿性陰道分泌物（風險比增加10～15倍）的發生風險增加，並且延後首次排卵時間。感染性病徵的增加說明免疫細胞功能可能受到影響。因此進一步探討NEFA和BHBA對於周邊血白血球的炎性細胞激素表現的影響。實驗結果指出 NEFA處理促進周邊血白血球發炎相關細胞激素表現（IL-1β、TNF-α和IL-8）。接著使用LPS與NEFA共培養，用以模擬產後感染狀態，亦發現NEFA會加強LPS誘導的細胞激素表現，但BHBA共培養並無此現象。發炎調控機制相當複雜，牽涉組織、免疫細胞和微生物之間的交互作用，但過度的發炎表現，則不利於採食量恢復和產後復舊。綜合以上結果，較高的脂肪代謝物會增加產後疾病風險，其原因可能來自免疫細胞的促發炎細胞激素的過度表現，導致產後復舊不佳。因此降低NEB程度，有助於減緩發炎，使牛隻順利度過轉換期。
關鍵字: 轉換期, 產後疾病、負能量平衡, 炎性細胞激素, 乳牛，NEFA, BHBA
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