董海波 倪迎冬
摘 要:選擇8頭安裝瘤胃瘺管的泌乳中期山羊隨機分為2組分別飼喂高精料日糧(60%干物質,HC組)和低精料日糧(40%干物質,LC組),實驗周期9周,期間采集瘤胃液,血液及肝臟組織。研究長期飼喂高精料日糧后肝臟中代謝底物的變化規律。實驗結果顯示:飼喂9周后,高精料日糧導致瘤胃液pH顯著下降;乳脂,乳蛋白也顯著下降;血漿中瘦素leptin(P=0.05),非酯化脂肪酸NEFA(P=0.07),葡萄糖glucose(P=0.014)均顯著上升;血漿皮質醇cortisol(P<0.05)水平顯著上升。肝臟中糖皮質激素受體GR蛋白與基因表達一致均顯著顯著下調(P<0.05);IL-1β,SAA,CRP及HP基因表達均顯著上升(P<0.05)。高通量芯片分析顯示與炎癥反應,脂代謝,蛋白代謝以及糖代謝的關鍵基因均發生顯著上調或下調,代謝調控網絡發生變化。結論 急性期反應與炎癥反應可能促進肝臟中能量重分配并最終導致乳品質下降。
關鍵詞:乳品質 急性期反應 炎癥反應 代謝 基因表達 肝臟 泌乳山羊
Long-term Effects of SARA on Milk Quality and Hepatic Gene Expression in Lactating Goats Fed a High-concentrate Diet
Dong Haibo Ni Yingdong
(Nanjing Agricultural University)
Abstract: Eight mid-lactating goats with rumen cannulas were randomly assigned to two groups. For 9 weeks, the treatment group was fed a high-concentrate diet (60% concentrate of dry matter, HC) and the control group was fed a low-concentrate diet (40% concentrate of dry matter, LC). Ruminal fluid, plasma, and liver tissues were sampled, microarray techniques and real-time polymerase chain reaction were used to evaluate metabolic parameters and gene expression in liver. Feeding a 60%-concentrate diet for 9 weeks resulted in a significant decrease in rumen pH. Changes in fat and protein content also occurred, which negatively affected milk quality. Plasma levels of leptin (P=0.058), non-esterified fatty acid (P=0.071), and glucose (P=0.014) increased markedly in HC group. Plasma cortisol concentration was significantly elevated in the treatment group (P<0.05). Expression of the glucocorticoid receptor protein gene was significantly down-regulated (P<0.05) in the liver. The expression of genes for interleukin 1b, serum amyloid A, C-reactive protein, and haptoglobin mRNA was significantly increased (P<0.05) in the HC group. GeneRelNet analysis showed that gene expression involved in inflammatory responses and the metabolism of lipids, protein, and carbohydrate were significantly altered by feeding a high-concentrate diet for 9 weeks.
Key Words: Milk quality; Acute phase response; Inflammatory response; Metabolism; Gene expression; Liver; lactating goats
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