- 學位論文
開發潛力益生乳酸菌作為飼料添加物
Development of Potentially Probiotic Lactic Acid Bacteria as Feed Additives
摘要
本研究之目的為開發抗病原菌、耐抗生素及具免疫調節性潛力益生菌之低成本培養基，並以冷凍乾燥之方式製作成商用飼料添加物。 第一部份研究中，將先前實驗中自豬隻及雞隻腸道或糞便檢體中經分離篩選所得之18株乳酸菌，進一步測試其病原菌抑制性 (Escherichia coli BCRC 10450、Staphylococcus aureus BCRC 10451及Salmonella typhimurium BCRC 10747)，抗生素敏感性及免疫調節作用。結果顯示，4株乳酸菌 (Lactobacillus johnsonii 2-1A、Lb. mucosae x-4w-1、Lb. johnsonii x-1d-2及Lb. mucosae 4-2B) 相較於其他菌株具有較佳之機能性，進而選定此4株乳酸菌進行後續試驗。 第二部份研究中，為配製上述4株乳酸菌之低成本培養基，以反應曲面法及序列二次規劃法求得高產量乳酸菌之最適化配方。結果顯示，乳酸菌以此培養基培養16小時後所得之菌數分別高達9.14、9.27、8.76及9.18 log CFU/mL，在驗證實驗中所得之菌數與反應曲面法預測所得者並無顯著差異。此外，此培養基之成本可降低至MRS培養基之1%以下。 研究中亦評估冷凍乾燥及微膠囊化對乳酸菌存活之影響。結果顯示，冷凍乾燥之乳酸菌粉於4°C下保存8週後仍能維持高量菌數，故選定冷凍乾燥之菌粉做為餵飼形式。以Lb. mucosae x-4w-1及Lb. johnsonii x-1d-2餵飼21日齡之離乳仔豬並觀察其對豬隻生長表現、糞便菌相及血清中免疫球蛋白含量之影響。結果顯示，在餵飼三週後仔豬血清中之IgG濃度有增加之情形。
並列摘要
The objective of this study was to develop a low-cost medium to cultivate potentially probiotic lactic acid bacteria (LAB) with antibacterial, antibiotic-tolerant and immunoregulatory activities and formulated these LAB using freeze-drying as commercial feed additives. In the first part of study, eighteen LAB strains, isolated from pig feces, chicken intestine and feces, were evaluated their antibacterial activities (Escherichia coli BCRC 10450, Staphylococcus aureus BCRC 10451 and Salmonella typhimurium BCRC 10747), antibiotic susceptibilities and immune-modulating effect (interleukin-6 (IL-6)). Results indicated that four lactobacilli including Lactobacillus johnsonii 2-1A, Lb. mucosae x-4w-1, Lb. johnsonii x-1d-2 and Lb. mucosae 4-2B showed better functional properties than the other strains. These four strains were selected for the next study. In the second part of study, we formulated the low-cost culture media for the above selected LAB. The response surface methodology and sequential quadratic programming methods were used to optimize the best formula to gain maximum populations of LAB. Results indicated that the cell counts of four LAB strains could reach to 9.14, 9.27, 8.76 and 8.99 log CFU/mL after a 16-hour incubation with the new media, respectively. The cell counts obtained from verification experiments were not significantly different to those from RSM-based prediction (P > 0.05). In addition, the cost of these new media was reduced to below 1% when compared with the price of MRS broth. The effects of freeze-drying and alginate encapsulation on the survival of probiotic lactobacilli were also evaluated. After 8 weeks of storage at 4°C, the viabilities of the tested LAB strains remained high in the freeze-dried powders. The freeze-dried powders containing LAB were used in subsequent feeding trail. The 21-day pre-weaning piglets were fed with Lb. mucosae x-4w-1 and Lb. johnsonii x-1d-2 isolated from porcine and investigated the effect of LAB feeding on the piglet’s growth performance, fecal microflora and serum immunoglobulin level. It was only showed that the serum IgG concentration of piglet increased after 3 weeks of feeding.