Penyakit yang sering menyerang ikan lele dumbo adalah penyakit bakterial yang disebabkan oleh bakteri aeromonas hydrophila. vitamin c dan ragi roti yang ditambahkan dalam pakan dapat meningkatkan resistensi ikan terhadap infeksi penyakit melalui peningkatan respons imun nonspesifik, sedangkan vitamin c berperan dalam pemeliharaan sistem kekebalan tubuh. penelitian ini bertujuan untuk mengetahui pengaruh penggunaan kombinasi pakan benih ikan lele dumbo (clarias gariepinus) yang diberi ragi roti (saccharomyces cereviciae) dan vitamin c untuk meningkatkan resisten benih ikan lele terhadap infeksi bakteri aeromonas hydrophila. penelitian ini dilaksanakan dari bulan april- mei 2022. hewan uji yang digunakan dalam penelitian ini yaitu ikan lele dumbo berukuran 6 cm yang dipelihara selama 41 hari. penelitian ini disusun menggunakan rancang acak lengkap (ral) dengan 4 perlakuan dan empat ulangan. perlakuan yang diterapkan adalah p0: pemberian pakan tanpa pemberian ragi roti dan vitamin c, p1; penambahan ragi roti 5g/kg pakan, p2: penambahan vitamin c 750 mg/kg pakan, dan p3: kombinasi penambahan vitamin c 750 dan ragi roti 5g ke dalam pakan komersil. hasil penelitian penambahan ragi roti dan vitamin c pada pakan komersil dapat meningkatkan ketahanan tubuh ikan lele terhadap infeksi bakteri aeromonas hydrophila, penambahan ragi roti dan vitamin c pada pakan komersil sebanyak 5/750 kg pakan yang diberikan ke ikan selama 21 hari berturut-turut, diperoleh sintasan ikan lele tertinggi setelah ikan di uji tantang dengan bakteri a.hydropilla yaitu pada perlakuan p3 sebesar 77%. kata kunci: aeromonas hydropilla, lele dumbo, ragi roti, vitamin c

The disease that often attacks african catfish is a bacterial disease aeromonas hyrophila. the additional of vitamin c and baker's yeast into feeds can enhance the resistance of fish to diseases infection through the enhancement of non-specific immune response, meanwhile vitamin c is to maintain the immune system. the objective of the research was to find out the effect of using baker's yeast and vitamin c into feeds of catfish (clarias gariepinus) to enhance the resistance of catfish seed to bacterial infection aeromonas hydrophila. it was conducted in april to may 2022. the testing fish in this research used catfish with 6 cm in length that were cultured for 41 days. this research was designed with a completely randomized design (crd) consisting of 4 treatments and 4 replications. the treatments were po: feed without baker's yeast and vitamin c, pi: feed with addition of 5 g/kg baker's yeast, p2: feed with addition of 750 mg/kg vitamin c, and p3. feed with combination of 750 mg vitamin c and 5 g baker's yeast. the findings showed that the addition of baker's yeast and vitamin c to commercial feed enhanced the resistance of catfish to bacterial infection aeromonas hydrophila. moreover, the addition of baker's yeast and vitamin c into commercial feed with 5 g and 750 per kg of pellet to catfish for 21 consecutive days after a.hydropilla infection obtained that the resistance of catfish in the treatment of p1 was 55%, p2 was 56%, and p3 was 77%, while control fish of po was 28%. keywords: aeromonas hydropilla, african catfish, baker's yeast, vitamin c