【摘要】：為了解高精料日糧對(duì)泌乳奶牛乳產(chǎn)量的影響,選擇12只健康經(jīng)產(chǎn)奶牛,分別飼喂精粗比為40∶60(對(duì)照組)和60∶40(高精料組)的日糧,試驗(yàn)期12周,每周監(jiān)測(cè)乳產(chǎn)量。試驗(yàn)期間每周采集血液樣品用于測(cè)定外周血生長(zhǎng)激素(GH)和胰島素樣生長(zhǎng)因子1(IGF-1)含量;試驗(yàn)結(jié)束,采集瘤胃液置-70℃保存待測(cè),肝臟和乳腺組織于液氮速凍后置-70℃保存待測(cè)。結(jié)果表明,高精料日糧的飼喂顯著降低了瘤胃pH(P0.05);奶牛外周血GH含量和IGF-1含量從第7周開(kāi)始顯著降低(P0.05);肝臟組織中生長(zhǎng)激素受體(GHR)、蛋白質(zhì)酪氨酸激酶2(JAK2)、信號(hào)傳導(dǎo)與轉(zhuǎn)錄激活子5A(STAT5A)及信號(hào)傳導(dǎo)與轉(zhuǎn)錄激活子5B(STAT5B)mRNA表達(dá)水平顯著下調(diào)(P0.05);乳腺組織中,胰島素樣生長(zhǎng)因子1受體(IGF-1R)mRNA表達(dá)水平顯著下調(diào)(P0.05)。結(jié)果提示,長(zhǎng)期飼喂高精料日糧會(huì)降低血液中GH和IGF-1含量,抑制GH-IGF-1軸的基因表達(dá)及關(guān)聯(lián)的JAK2-STAT5信號(hào)途徑的相關(guān)基因表達(dá),從而減少了乳產(chǎn)量。
[Abstract]:In order to understand the effect of high concentrate diet on milk yield of lactating cows, 12 healthy dairy cows were fed with the diets of 40:60 (control group) and 60:40 (high concentrate group), respectively. The milk yield was monitored weekly during the experiment period of 12 weeks. The peripheral blood growth hormone (GH) and insulin-like growth factor-1 (IGF-1) were measured by sampling blood samples every week during the experiment. At the end of the experiment, the rumen fluid was collected and stored at-70 鈩，

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