本文關鍵詞： 綿羊 小肽 游離氨基酸 轉(zhuǎn)運載體 mRNA表達　出處：《畜牧獸醫(yī)學報》2017年03期 　論文類型：期刊論文

【摘要】：旨在研究綿羊胃腸道內(nèi)游離氨基酸(FAA)和小肽(PAA)的數(shù)量分布和堿性氨基酸轉(zhuǎn)運載體CAT1、酸性氨基酸轉(zhuǎn)運載體EAAT3、中性氨基酸轉(zhuǎn)運載體y+LAT2和ASCT2、小肽轉(zhuǎn)運載體PepT1、氨基肽酶APN、二肽酶DPEP2mRNA在胃腸道的表達規(guī)律。試驗選取18月齡健康小尾寒羊6只,屠宰后收集瘤胃、十二指腸、空腸、回腸和盲腸的食糜及對應腸道組織,對食糜上清液的小肽和游離氨基酸進行測定,并用實時定量PCR對基因表達量進行測定。結果顯示:1)綿羊食糜多數(shù)游離氨基酸濃度從高到低的分布為空腸、十二指腸、回腸、瘤胃和盲腸,前二者顯著高于其他部位(P0.05);不同部位游離氨基酸組成比例不同;多數(shù)小肽濃度從高到低的分布為十二指腸、空腸、回腸、盲腸和瘤胃,除瘤胃和盲腸外各部位間差異顯著(P0.05);不同部位小肽的組成比例不同;小肽占總氨基酸(TAA)的比例在空腸顯著低于其他部位(P0.05)。2)CAT1mRNA在空腸表達量最高,但不同部位間差異不顯著;EAAT3、y+LAT2、PepT1、APN mRNA表達規(guī)律相似,均在回腸表達量最高;ASCT2mRNA在十二指腸表達量最高,DPEP2mRNA在盲腸表達量最高。結果提示,胃腸道不同區(qū)段游離氨基酸和小肽的濃度和組成不同;游離氨基酸的主要釋放部位是空腸,主要吸收部位是回腸;小肽的主要釋放部位是十二指腸,主要消化部位是空腸,在腸系膜系統(tǒng)的主要吸收部位是回腸;瘤胃和小腸各區(qū)段吸收堿性氨基酸的能力基本相同;酸性和多數(shù)中性氨基酸主要吸收部位是回腸,少數(shù)中性氨基酸主要吸收部位是空腸。本研究為綿羊小腸氨基酸營養(yǎng)和蛋白質(zhì)消化吸收規(guī)律的研究提供了理論依據(jù)。
[Abstract]:The aim of this study was to study the quantitative distribution of free amino acid (FAA) and small peptide (PAA) in the gastrointestinal tract of sheep and their basic amino acid transport vector CAT1, acid amino acid transport vector EAAT3, neutral amino acid transport vector y LAT2 and ASCT2, small peptide transport vector PepT1, aminopeptidase. The expression of APN, dipeptidase DPEP2mRNA in gastrointestinal tract was studied in 6 healthy 18-month-old small tail Han sheep. The chyme and corresponding intestinal tissue of rumen duodenum jejunum ileum and cecum were collected after slaughter and the small peptides and free amino acids in supernatant of chyme were determined. The gene expression was determined by real-time quantitative PCR. The results showed that the concentration of most free amino acids in chyme of sheep from high to low were jejunum, duodenum, ileum, rumen and cecum. The first two were significantly higher than other parts (P 0.05), the proportion of free amino acids in different parts were different, and the distribution of most small peptides from high to low were duodenum, jejunum, ileum, cecum and rumen. There were significant differences between different parts except rumen and cecum (P 0.05); the proportion of small peptide in different parts was different; the proportion of small peptide to total amino acid (TAA) was significantly lower in jejunum than that in other parts (P 0.05) .2CAT1 mRNA expression was the highest in jejunum. However, there was no significant difference between different sites in the expression of APN mRNA in EAAT3T _ (2) and PepT _ (1) T _ (1), which were the highest in the ileum and the highest in duodenum and the highest in the cecum. The results suggested that the expression of Asct2mRNA was the highest in the duodenum, and the expression of DPEP2mRNA was the highest in the cecum. The concentration and composition of free amino acids and small peptides in different regions of the gastrointestinal tract are different. The main releasing sites of free amino acids are jejunum, the main absorption part is ileum, the main release site of small peptide is duodenum, and the main part of digestion is jejunum. The main absorption site of mesenteric system is ileum; the ability of absorption of basic amino acids in rumen and small intestine is basically the same; the main absorption site of acid and most neutral amino acids is ileum. A few neutral amino acids are mainly absorbed in jejunum. This study provides a theoretical basis for the study of amino acid nutrition and protein digestion and absorption in sheep small intestine.
【作者單位】： 西北農(nóng)林科技大學動物科技學院;
【基金】：基金項目:國家絨毛用羊產(chǎn)業(yè)技術體系(CARS-40-13) 北方作物秸稈飼用化利用技術研究與示范(201503134)
【分類號】：S826

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