Seleksi dan identifikasi bakteri asam laktat yang berproliferasu pada tembolok dan usus halus ayam kampung

NURHAYATI, Sitasari, Dr. Ir. Lies Mira Yusiati, SU

2008 | Tesis | S2 Ilmu Peternakan

Penelitian ini bertujuan untuk mendapatkan bakteri asam laktat (BAL) yang mempunyai kriteria sebagai kandidat probiotik dan mempunyai ketahanan terhadap kondisi aerob yang diambil dari epitel tembolok dan atau usus halus ayam kampung. Isolasi dilakukan dengan menggunakan medium MRS (de Man Rogosa Sharpe) secara anaerobik suhu 37oC selama 24 jam. Seleksi awal berdasarkan pada produksi asam laktat, tipe katalase, tipe fermentasi dan gram staining. Isolat dengan produksi asam laktat tertinggi diuji aktivitas bakteriosin (metode turbidimetric assay) dengan bakteri indikator Staphylococcus aureus FNCC 0047. BAL yang mempunyai aktivitas paling tinggi selanjutnya diuji ketahanannya terhadap suhu (30 dan 41oC), pH rendah (1, 2, dan 3), simulasi getah lambung (pepsin 0,3% pH 2), simulasi getah pankreas (pankreatin 0,5% pH 8) dan simulasi garam empedu (garam empedu 0,3%), dan kondisi aerob (agitasi 0 dan 100 rpm). Data optical density (OD) pertumbuhan bakteri pada uji bakteriosin, ketahanan terhadap suhu, dan kondisi aerob dianalisis dengan program SPSS 11,5 untuk Window dengan desain doubly multivariate repeated measurements. One-way analysis of variance (ANOVA) dengan step-down multiple-stage F post hoc test (Duncan multiple F-test pada P<0,01 atau 0,05) digunakan untuk membedakan rerata antar perlakuan termasuk untuk data total koloni (log CFU/ml) pada uji ketahanan terhadap pH rendah, simulasi getah lambung, getah pankreas dan garam empedu. Dari isolasi awal diperoleh 33 isolat yang kemudian dipilih 18 isolat untuk diuji produksi asam laktat, tipe katalase, tipe fermentasi dan gram staining. Dari isolat yang diuji diambil isolat dengan kadar asam laktat tertinggi, memiliki tipe katalase negatif, tipe fermentasi negatif, dan gram staining positif, dan isolat yang terpilih adalah satu dari tembolok (BAL ST1) dan satu dari usus halus (BAL SU5). Aktivitas bakteriosin BAL SU5 secara nyata lebih tinggi dibandingkan dengan BAL ST1. Hasil pengujian selanjutnya menunjukkan bahwa BAL SU5 mempunyai sifat tahan terhadap pH 3, tahan terhadap simulasi getah lambung, simulasi getah pankreas, simulasi garam empedu, dan kondisi aerob sehingga dapat menjadi kandidat untuk bakteri probiotik.

The objective of this study was to isolate lactic acid bacteria (LAB) to be a candidate for probiotic microbe. The LAB was isolated from the bacteria that proliferated on the epithelium of the crop and the small intestine of native chicken using MRS (de Man Rogosa Sharpe) medium and incubated at 39oC for 24 hours under unaerobic condition. The selection was based on lactic acid production, catalase type, fermentation type, gram staining and cell morphology. Two isolates with the highest lactic acid production were than tested for bacteriocin activity with Staphylococcus aureus FNCC 0047 as indicator bacteria. The LAB with higher activity of bacteriocin was be tested for its tolerance to temperature (30 and 41oC), low pH (1, 2, and 3), simulated gastric juice (pepsin 0.3% pH 2), simulated pancreatic juice (pancreatin 0.5% pH 8), simulated bile salt (bile salt 0.3%) and aerobic conditions (0 rpm and 100 rpm). The data concerning optical density (OD) of the growth of bacteria from the test of bacteriocin activity and the tolerance to temperature and aerobic conditions were analyzed by SPSS 11.5 for Window with doubly multivariate repeated measurements design. One-way analysis of variance (ANOVA) with step-down multiple-stage F post hoc test (Duncan multiple F-test on P<0.01 or 0.05) was used to distinguish treatment mean differences including viable count (log CFU/ml) from the test of the tolerance to low pH, simulated gastric juice, simulated pancreatic juice, and simulated bile salt conditions. Eighteen isolates from the 33 isolates obtained from crop and small intestine of a native chicken were tested for acid lactic production, catalase type, fermentation type, and gram staining. Isolate with the highest lactic acid production were taken one from the crop (ST1) and one from the small intestine (SU5). Both had negative test for catalase and fermentation type, and positive test for gram staining. Bacterocin activity of BAL SU5 significantly had the higher than bacterosin activity of LAB ST1. Since LAB SU5 had tolerance to pH 3, simulated gastric juice, simulated pancreatic juice, simulated bile salt, and aerobic conditions, it has a chance to become a good candidate for probiotic bacteria.

Kata Kunci : bakteri asam laktat,Tembolok,Usus halus,Ayam kampung, Lactic acid bacteria, Crop, Small intestinum, Native chicken, Bacteriocin