【摘要】：腸道和骨骼是機體重要的消化吸收場所和支柱器官，維護其健康穩(wěn)態(tài)對機體生長發(fā)育具有重要意義。蛋氨酸(MET)是人體必需氨基酸，其替代源包括蛋氨酸羥基類似物(HMTBA)和蛋氨酸羥基類似物鈣鹽(HMTB-Ca)。由于結(jié)構(gòu)上的差異，HMTBA和HMTB-Ca相較于DL-蛋氨酸(DLM)可能具有較強的抗氧化活性，對維護腸道氧化還原穩(wěn)態(tài)以及促進(jìn)骨骼發(fā)育具有積極作用。本論文比較分析了DLM、HMTBA和HMTB-Ca的體外抗氧化活性；并以生長周期短，代謝強度大的肉雞作為研究對象，研究了不同水平蛋氨酸源對肉雞生長性能、營養(yǎng)物質(zhì)消化吸收、腸道氧化還原狀態(tài)以及骨骼發(fā)育的影響，初步探討了其可能的抗氧化作用機制。 體外部分：考察了DLM、HMTBA和HMTB-Ca對O-2·清除率和對小鼠肝臟質(zhì)過氧化抑制率；體內(nèi)部分：210只1日齡雄性羅斯肉雞，按體重隨機分為7組：對照組（無外源性蛋氨酸源添加）、試驗組分別飼喂添加DLM、HMTBA及HMTB-Ca的試驗飼糧，添加水平分別為0.2%和0.3%(前期)，0.1%和0.2%(后期)。于實驗第21天和46天采樣，分析各組實驗動物生長性能、對營養(yǎng)物質(zhì)消化吸收率、腸道氧化還原狀態(tài)及骨骼發(fā)育相關(guān)指標(biāo)，并考察了腸道及骨骼組織相關(guān)基因的mRNA表達(dá)水平。 本論文主要研究結(jié)果如下：(1)體外O-2·清除能力：HMTBADLMHMTB-Ca；體外小鼠肝臟脂質(zhì)過氧化抑制率：HMTBAHMTB-CaDLM。(2)肉雞飼喂三種蛋氨酸源21天和46天均可提高動物日增重和采食量，且有一定的劑量-效應(yīng)關(guān)系；與DLM組相比，肉雞飼喂HMTBA和HMTB-Ca21天可顯著提高日增重和采食量(P0.05)，飼喂46天可顯著提高日增重(P0.05)，且高劑量HMTBA和HMTB-Ca組效果最為顯著。(3)與DLM組相比，，高劑量的HMTBA組和HMTB-Ca組腸道淀粉酶和脂肪酶活力顯著增強(P0.05)，HMTB-Ca組對營養(yǎng)物質(zhì)的表觀消化率提高；46天肉雞飼喂高劑量HMTBA和HMTB-Ca可顯著提高十二指腸和空腸絨毛長度/隱窩深度比值(V/C)(P0.05)，降低生長抑素(SS)分泌水平。(4)肉雞飼喂HMTBA和HMTB-Ca顯著提高十二指腸和空腸GSH/GSSG比值和CAT活性(P0.05)，降低MDA水平(P0.05)；上調(diào)十二指腸和空腸抗氧化相關(guān)基因NRF1、SOD1、SOD2、GST、PGC-1α、MT1mRNA表達(dá)水平。(5)與DLM組相比，肉雞飼喂高劑量HMTBA和HMTB-Ca可顯著提高脛骨、股骨骨骼強度和骨骼指數(shù)(P0.05)，飼喂HMTB-Ca可顯著提高脛骨、股骨鈣、磷含量(P0.05)，并且顯著下調(diào)骨分解關(guān)鍵基因MMP2、MMP9mRNA表達(dá)水平(P0.05)。
[Abstract]:Intestinal tract and bone are important digestive and absorption sites and pillar organs, and maintaining their health and steady-state is of great significance to the growth and development of the body. Methionine (MET) is an essential amino acid in human body. Its alternative sources include methionine hydroxyl analogues (HMTBA) and methionine hydroxyl analogues (HMTB-Ca). Compared with DL-methionine (DLM), HMTBA and HMTB-Ca may have stronger antioxidant activity than DL-methionine (DLM), and play a positive role in maintaining redox homeostasis and promoting bone development. In this paper, the antioxidant activities of DLM-HMTBA and HMTB-Ca in vitro were comparatively analyzed, and the growth performance, digestibility and absorption of nutrients of broilers with different levels of methionine were studied by using the broilers with short growth cycle and high metabolic intensity. The effects of intestinal redox state and bone development on the mechanism of antioxidation were preliminarily discussed. In vitro, the effects of DLMN HMTBA and HMTB-Ca on the scavenging rate of O-2 and the inhibition rate of liver peroxidation in mice were investigated, and 210 one-day-old male Roth broilers were selected. According to body weight, the rats were randomly divided into 7 groups: control group (without exogenous methionine source), the experimental diet supplemented with DLMM-HMTBA and HMTB-Ca, the supplementation levels were 0.2% and 0.3% (Prophase) and 0.2% (later), respectively. On the 21st and 46th days of the experiment, the growth performance, the digestibility of nutrients, the redox state of the intestine and the related indexes of bone development were analyzed, and the mRNA expression level of the genes related to the intestinal tract and bone tissue were investigated. The main results of this study were as follows: (1) the in vitro O-2 scavenging capacity of 1: HMTBADLMHMTB-Caand the inhibition rate of lipid peroxidation in mice liver in vitro. (2) three methionine sources fed to broilers for 21 and 46 days could increase the daily gain and feed intake. Compared with DLM group, HMTBA and HMTB-Ca21 increased daily gain and feed intake significantly (P0.05), fed 46 days significantly increased daily gain (P0.05), and the effect of high dose HMTBA and HMTB-Ca groups was the most significant. (3) compared with DLM group, the effect of high dose HMTBA and HMTB-Ca groups was the most significant. The activities of amylase and lipase in high dose HMTBA group and HMTB-Ca group were significantly increased (P0.05) the apparent digestibility of nutrients was increased in HMTB-Ca group. High-dose HMTBA and HMTB-Ca significantly increased the ratio of villi length to crypt depth in duodenum and jejunum (P0.05) and decreased the level of somatostatin (SS) secretion. (4) HMTBA and HMTB-Ca significantly increased GSH/GSSG ratio of duodenum and jejunum. The activity of CAT (P0.05) decreased the level of MDA (P0.05). (5) compared with DLM group, high dose of HMTBA and HMTB-Ca significantly increased tibia, bone strength and bone index (P0.05), and fed HMTB-Ca significantly increased tibia calcium. P content (P0.05), and significantly down-regulated the expression level of MMP2 and MMP9 mRNA (P0.05).
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：R151.1

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本文編號：2150250