Electronic Theses and Dissertation

Penelitian ini dimaksudkan untuk melakukan identifikasi kandidat bakteri asam laktat (bal) yang terdapat pada saluran cerna cecum ayam persilangan alpu dan kub turunan ketiga melalui pengamatan karakterisasi jumlah koloni, morfologi, toleransi ph, serta daya hambat terhadap bakteri patogen. tempat penelitian dilaksanakan di laboratorium lapangan peternakan (llp) dan laboratorium penyakit tanaman, fakultas pertanian, universitas syiah kuala, darussalam, banda aceh. metode penelitian yang dipergunakan ialah metode eksperimen, menggunakan rancangan acak lengkap faktorial (ralf), dengan faktor pertama jenis pakan dan faktor kedua jenis kelamin ayam (jantan dan betina). jenis pakan yang digunakan adalah p0 (100% pakan komersial), p1 (100% pakan fermentasi), p2 (50% pakan komersial + 50% pakan fermentasi), dan p3 (70% pakan komersial + 30% pakan fermentasi). variabel yang diamati meliputi jumlah koloni bal, morfologi koloni, toleransi ph, dan daya hambat terhadap bakteri patogen. data jumlah koloni bal dianalisis melalui analisis ragam (anova) dan diteruskan dengan uji duncan, sedangkan data morfologi, toleransi ph, dan daya hambat dianalisis secara deskriptif kualitatif. temuan penelitian memperlihatkan bahwasanya jumlah koloni bal tertinggi terdapat pada perlakuan p1, baik pada ayam jantan (rata-rata 8,44 log cfu/ml) maupun betina (rata rata 8,44 log cfu/ml). sebaliknya, jumlah koloni terendah terdapat pada perlakuan p0 jantan (rata-rata 7,94 log cfu/ml). hal tersebut membuktikan bahwa pakan fermentasi mampu meningkatkan populasi bal pada cecum ayam. pengamatan morfologi menunjukkan bahwa isolat bal memiliki koloni berbentuk bulat dengan tepian halus hingga bergelombang, warna koloni putih hingga krem, bentuk sel basil, serta elevasi cembung. variasi ini menunjukkan adanya keragaman karakter fenotip bal yang tumbuh pada media mrs agar. hasil uji ph menunjukkan bahwa isolat bal mampu menurunkan ph dari kisaran awal 5,8–6,2 menjadi ph akhir 4,4–4,6. penurunan ph ini mengindikasikan kemampuan bal dalam menghasilkan asam laktat yang berperan penting dalam menghambat pertumbuhan bakteri patogen di saluran pencernaan. uji daya hambat terhadap bakteri patogen (micrococcus luteus, bacillus cereus, staphylococcus aureus, dan escherichia coli) menunjukkan bahwa isolat bal mempunyai aktivitas antagonistik dengan diameter zona hambat berkisar antara 0,4–0,8 cm. aktivitas penghambatan terbesar ditunjukkan oleh isolat perlakuan p1b dengan zona hambat mencapai 0,8 cm terhadap staphylococcus aureus dan escherichia coli. berdasarkan hasil penelitian, dapat disimpulkan bahwa cecum ayam persilangan alpu dan kub yang diberi perlakuan pakan fermentasi yang mengandung probiotik dan enzim pencernaan dapat menghasilkan kandungan isolat bakteri asam laktat yang memiliki karakteristik sesuai dengan sifat dasar bal dan sangat berpotensi sebagai kandidat probiotik untuk unggas. disarankan penelitian lebih lanjut dilakukan menggunakan metode identifikasi molekuler untuk menentukan spesies bal secara spesifik, serta uji in vivo untuk melihat pengaruhnya terhadap performa ayam. kata kunci : bakteri asam laktat, cecum, alpu, kub, pakan fermentasi, probiotik

This study aimed to identify candidates for Lactic Acid Bacteria (LAB) in the cecum of the third generation of ALPU and KUB crossbred chickens through observations of the characterization of the number of colonies, morphology, pH tolerance, and inhibitory power against pathogenic bacteria. The research location was carried out at the Animal Husbandry Field Laboratory (LLP) and the Plant Disease Laboratory, Faculty of Agriculture, Syiah Kuala University, Darussalam, Banda Aceh. The research method used was an experimental method, using a Completely Randomized Factorial Design (RALF), with the first factor being the type of feed and the second factor being the sex of the chicken (male and female). The types of feed used were P0 (100% commercial feed), P1 (100% fermented feed), P2 (50% commercial feed + 50% fermented feed), and P3 (70% commercial feed + 30% fermented feed). The variables observed included the number of LAB colonies, colony morphology, pH tolerance, and inhibitory power against pathogenic bacteria. LAB colony count data were analyzed using Analysis of Variance (ANOVA) and then Duncan's test. Morphology, pH tolerance, and inhibitory activity data were analyzed descriptively and qualitatively. The research findings showed that the highest LAB colony count was found in the P1 treatment, both in male chickens (average 8.44 log CFU/mL) and female chickens (average 8.44 log CFU/mL). Conversely, the lowest colony count was found in the P0 male chicken treatment (average 7.94 log CFU/mL). This demonstrates that fermented feed can increase LAB populations in chicken cecum. Morphological observations revealed that LAB isolates had round colonies with smooth to wavy edges, white to cream colony color, bacillus cell shape, and convex elevations. This variation indicates the diversity of LAB phenotypic characteristics growing on MRS agar media. The pH test results showed that LAB isolates were able to lower the pH from an initial range of 5.8–6.2 to a final pH of 4.4–4.6. This decrease in pH indicates the ability of LAB to produce lactic acid, which plays a crucial role in inhibiting the growth of pathogenic bacteria in the digestive tract. Inhibitory tests against pathogenic bacteria (Micrococcus luteus, Bacillus cereus, Staphylococcus aureus, and Escherichia coli) showed that LAB isolates exhibited antagonistic activity, with inhibition zones ranging from 0.4–0.8 cm in diameter. The greatest inhibitory activity was demonstrated by the P1B isolate, with an inhibition zone reaching 0.8 cm against Staphylococcus aureus and Escherichia coli. Based on the research results, it can be concluded that the cecum of crossbred ALPU and KUB chickens fed fermented feed containing probiotics and digestive enzymes can produce lactic acid bacteria isolates with characteristics consistent with LAB and have great potential as probiotic candidates for poultry. Further research is recommended using molecular identification methods to determine specific LAB species, as well as in vivo testing to determine their effects on chicken performance. Keywords: Lactic Acid Bacteria, Cecum, ALPU, KUB, Fermented Feed, Probiotics