EKSPLORASI BAKTERI ASAM LAKTAT SEBAGAI KANDIDAT PROBIOTIK PADA LELE DUMBO (Clarias sp.)

Dian Fitri Anggraini, Dr. Ir. Triyanto, M .Si.

2013 | Tesis | S2 Bioteknologi

Tujuan dari penelitian ini adalah untuk mengekplorasi bakteri asam laktat yang diisolasi dari ikan peda, tanah tambak, saluran pencernaan kepiting, udang, ikan lele, nila, dan karper sebagai kandidat probiotik untuk mengatasi penyakit yang disebabkan oleh bakteri patogen pada lele dumbo ( Clarias sp.). Sebanyak 114 isolat didapat dan 87 isolat bakteri asam laktat (BAL) yang memiliki zona jernih pada medim GYP dengan tambahan CaCO 3 diuji aktivitas antagonisnya terhadap A. hydrophila, A. salm onicida, E. ictaluri, dan E. tarda menggunakan metode difusi agar double layer. Isolat KP8 yang memiliki aktivitas penghambatan terbesar dipilah untuk dilakukan identifikasi dan uji daya lekat pada mucus dan uji kompetisi terhadap patogen. Uji daya lekat pada mukus lele dumbo menunjukkan bahwa isolat KP 8 memiliki daya lekat sebesar 33,11% pada mucus saluran pencernaan lele dumbo, sedangkan A. hydrophila memiliki daya lekat sebesar 18,36%, A. salmonicida 13,43%, E. tarda 18,64%, dan E. ictaluri 21,45%. Uji daya kompetitif terhadap A. hydrophila dengan metode eksklusi KP8 memiliki persentase jumlah sel/bidang pengamatan sebesar 77,07%, kompetisi 73,08%, dan displacement 74,60%; terhadap A. salmonicida dengan metode eksklusi 72,27%, kompetisi 74,36%, dan displacement 74,02%; terhadap E. tarda dengan metode eksklusi 68,24%, kompetisi 67,02%, dan displacement 66,50%; serta terhadap E. ictaluri dengan metode eksklusi 68,56%, kom petisi 65,18%, d an displacement 66,77%. Hasil analisis statistik menggunakan student t-test menunjukkan menunjukkan bahwa persentase jumlah sel KP 8 berbeda nyata dengan jumlah sel A. hydrophila, A. salmonicida, E. tarda, dan E. ictaluri tetapi keberadaannya tidak dapat m enurunkan daya lekat bakteri pathogen tersebut. Identifikasi molekuler dengan sekuensing 16S rDNA menunjukkan bahwa isolat KP8 memiliki kekerabatan paling dekat dengan Leuconostoc mesenteroides.

The purpose of the research was to explore lactic acid bacteria isolated from peda, land farm, gastrointestinal of crabs, shrimps, African catfish, nile, and carps as a probiotic candidate to handle the diseases caused of pathogen bacteria in African catfish (Clarias sp.). One hundred and fourteen bacterial isolates were get from peda, land farm, gastrointestinal of crabs, shrimps, african catfish, nile tilapia, and carps and eighty seven of them had cle ar zone on GYP medium with addition of CaCO 3. Their antagonism activities were determined against A. hydrophila, A. salmonicida, E. tarda, and E. ictaluri using double layer disk diffusion method. KP8 isolate that had the biggest antagonism activity were chosen for the next research. The adhesion abilities of KP8 and four fish pathogen were determine to mucus form African catfish intestinal. KP8 had adhesion ability 33,11% to intestinal mucus, A. hydrophila 18,36%, A. salmonicida 13,43%, E. tarda 18,64%, and E. ictaluri 21,45%. Competition test to A. hydrophila using exclusion method showed that the percentage of cell num ber of KP8 were 77,07% ; 73,08% using competition method, and 74,60% using displacement. Competition test to A. salmonicida showed that the percentage of cell number of KP8 were 72,27% in exclusion, 74,36% in competition, 74,02% in displacement. Competition test to E. tarda using exclusion method showed that the percentage of cell number of KP 8 were 68,24%, 67,02% using compe tition method, and 66,50% using displacement method. Competition test to E. ictaluri using exclusion method showed that the percentage of cell num ber of KP8 were 68,56%, 65,18% using competition method, and 66,77% using displacement method. Statistical analysis using student t-test resulted that the percentage of cell number of KP8 was significantly different from percentage of cell number of all pathogen tested but the presence of KP8 could not decrease them. The molecular identification using 16S rD NA sequencing showed that KP8 has the closest similarities to Leuconostoc mesenteroides.

Kata Kunci : Bakteri asam laktat, Lele D umbo, Probiotik, Daya lekat, Kompetisi, Identifikasi molekuler, Leuconostoc mesenteroides