本文選題：益生菌 + 屎腸球菌　； 參考：《山東農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：益生菌作為一種飼料添加劑,在畜牧業(yè)生產(chǎn)中得到越來越廣泛的應(yīng)用,其飼喂效果也得到了畜牧從業(yè)者和學(xué)者的廣泛認(rèn)可。但益生菌的益生特性表現(xiàn)出較為明顯的菌株差異,因此要得到益生性能優(yōu)良的益生菌株,就要進(jìn)行大量的篩選工作。實(shí)驗(yàn)室前期分離保存了一株具有高膽鹽耐受特性的益生菌,本課題對該株益生菌的種屬、益生特性及安全性進(jìn)行了系統(tǒng)的研究。具體研究內(nèi)容及結(jié)果如下:(1)通過形態(tài)學(xué)觀察、生化鑒定及16S rDNA序列比對分析,確定該菌株為屎腸球菌(Enterococcus faecium),并命名為屎腸球菌SQ-1。(2)對該株菌開展了體外益生特性研究,實(shí)驗(yàn)結(jié)果表明:SQ-1具有較好的耐酸、耐膽鹽、耐高溫、耐消化酶等特性。在p H2.0的條件下培養(yǎng)3h仍有61.93%的存活率;在膽鹽濃度為0.3%的條件下培養(yǎng)3h有90.37%的存活率,膽鹽濃度達(dá)0.6%時仍有49.7%的存活率;在60℃環(huán)境中處理15min仍有77.66%的存活率;經(jīng)過1.2%的胰蛋白酶處理3h后有31.01%的存活率。這些實(shí)驗(yàn)結(jié)果表明該株菌具有較好的抗逆性,且對高濃度膽鹽的耐受性較為突出。采用碳?xì)浠衔镳ぶz測該菌的疏水性,結(jié)果表明SQ-1疏水率為34.53%,具有中等疏水性。在對沙門氏菌(CVCC 3377)和金黃色葡萄球菌(CICC23926)的抑菌實(shí)驗(yàn)中,抑菌圈直徑分別為11mm和13mm,具有中等抑菌作用。(3)進(jìn)行了SQ-1對小鼠單核-巨噬細(xì)胞吞噬功能和血清中IgG、IL-2含量影響的研究。碳粒廓清實(shí)驗(yàn)結(jié)果表明,口服1×109cfu/mL的屎腸球菌SQ-1組與對照組比較,廓清指數(shù)出現(xiàn)顯著性(P0.05)升高,表明該菌株對小鼠的吞噬功能具有顯著的增強(qiáng)作用;血清中IgG含量檢測結(jié)果顯示,口服1×109cfu/mL的屎腸球菌SQ-1組與對照組相比較,IgG含量有極顯著性(P0.01)升高;而IL-2含量無顯著性差異。這些實(shí)驗(yàn)結(jié)果,說明屎腸球菌SQ-1對小鼠的免疫功能具有增強(qiáng)作用。(4)對屎腸球菌SQ-1開展了安全性研究,實(shí)驗(yàn)包括:對20種抗生素敏感性檢測、毒力基因PCR檢測和小鼠口服屎腸球菌SQ-1后的臟器指數(shù)、血常規(guī)檢測以及組織切片觀察等�？股孛舾行詫�(shí)驗(yàn)結(jié)果表明,屎腸球菌SQ-1對8種抗生素敏感,其中最具有代表性的萬古霉素抑菌圈直徑為19mm;對常見的六種毒力基因(Asa1、cyl A、efaA、esp、gel E、hyl)的PCR檢測結(jié)果表明,屎腸球菌SQ-1不存在這六種毒力基因。在口服屎腸球菌SQ-1的安全性研究中,實(shí)驗(yàn)組和對照組相比較,臟器指數(shù)和血常規(guī)檢測均無顯著性差異;組織切片觀察顯示無病理變化,上述的安全性實(shí)驗(yàn)結(jié)果表明,屎腸球菌SQ-1的安全性較高。綜上所述,屎腸球菌SQ-1具有較好的抗逆性和益生特性,同時安全性較好,這些為該菌株的生產(chǎn)開發(fā)提供了理論依據(jù),也說明了該菌株有較好的應(yīng)用前景。
[Abstract]:Probiotics, as a kind of feed additive, are more and more widely used in animal husbandry, and their feeding effect has been widely recognized by animal husbandry practitioners and scholars. But the probiotic characteristics of probiotics show obvious differences, so to obtain probiotic strains with good probiotics, we must carry out a lot of screening work. A probiotic strain with high bile salt tolerance was isolated and preserved in laboratory. The species, probiotics and safety of the probiotic strain were systematically studied in this paper. The specific contents and results are as follows: (1) by morphological observation, biochemical identification and 16s rDNA sequence alignment analysis, the strain was identified as Enterococcus faecium), and named as Enterococcus faecium SQ-1. (2) the probiotics of this strain were studied in vitro. The results show that: SQ-1 has good acid resistance, bile salt resistance, high temperature resistance and digestive enzyme resistance. The survival rate was 61.93% at pH 2.0 for 3 h, 90.37% for bile salt concentration for 3 h, 49.7% for bile salt concentration, 77.66% for 15min treated at 60 鈩，

本文編號：2112524