Judul: Pengaruh penambahan ragi bir dalam pakan terhadap daya tahan tubuh ikan lele Clarias sp dari infeksi bakteri Aeromonas hydrophila
Abstrak: Motile aeromonad septicaemia caused by Aeromonas hydrophila, induced serious epidemics disease in freshwater fish, one of them is Clarias sp. This research was purposed to evaluate the feeding period of brewer's yeast Saccharomyces cerevisae on the resistance of Clarias sp against A. hydrophila infection. Clarias sp with an initial body weight of 5.33±0.5 g were cultured for 30 days in 50 x 40 x 35 cm aquarium. During rearing period, fish were fed on the diet contained either 0% or 3% of S. cerevisae. On day10, fishin the groups of K+10 (feeding with 0% S. cerevisae) and RB10 (feeding with 3% S. cerevisae), were infected with A. hydrophila; while those fish in the groups of K+20 and RB20 were infected on day 20. Fish in the group of K- were not infected with A. hydrophila. The results showed that on day-30, fish in the groups of K-, RB10, and RB20 had significantly higher survival than fish in K+10 and K+20. The survival of fish in K-, RB10, and RB20 were 100%, 76.7%, and 73.3%, respectively; while those in K+10 and K+20 were only 26,7% and 33.3%, respectively. Therefore, feeding on S. cerevisae in the period of ten days effectively reduce the mortality of fish due to the infection of A.hydrophila., Penyakit motile aeromonad septicaemia yang disebabkan oleh Aeromnas hydrophila menyebabkan wabah penyakit serius pada ikan air tawar, salah satunya ikan lele dumbo Clarias sp. Penelitian ini bertujuan untuk mengevaluasi efektivitas lama periode pemberian ragi bir Saccharomyces cerevisae sebagai pakan ikan yang dapat meningkatkan daya tahan tubuh ikan lele dumbo. terhadap infeksi bakteri A. hydrophila. Ikan lele ukuran 5,33±0,5 g dipelihara dalam akuarium ukuran 50 x 40 x 35 cm dengan padat tebar 10 ekor/akuarium, selama 30 hari. Selama masa budidaya, ikan diberi 3% ragi bir dalam pakan dan pakan tanpa ragi bir. Perlakuan yang diujikan adalah lama pemberian pakan yang berbeda sebelum ikan diinfeksi bakteri. Perlakuan tersebut adalah: RB10 (pakan formulasi dengan 3% ragi bir, ikan diinfeksi A. hydrophila pada hari ke-10); RB20 (pakan formulasi dengan 3% ragi bir, ikan diinfeksi A. hydrophila pada hari ke-20); K+10 (pakan formulasi tanpa ragi bir, ikan diinfeksi A. hydrophila pada hari ke-10); K+20 (pakan formulasi tanpa ragi bir; serta ikan diinfeksi A. hydrophila pada hari ke-20) dan perlakuan kontrol, yaitu K- (pakan formulasi tanpa ragi bir serta tanpa diinfeksi A. hydrophila). Hasil penelitian menunjukkan bahwa pada hari ke-30 masa budidaya, nilai kelangsungan hidup yang tinggi diperoleh pada perlakuan K-, RB10, dan RB 20, yakni masing-masing 100%, 76,7%, dan 73,3%. Sedangkan kelangsungan hidup ikan pada perlakuan K+10 dan K+20, masing-masing 26,7% dan 33,3%. Dengan demikian, pemberian ragi bir selama 10 hari dapat menekan kematian ikan lele akibat serangan bakteri A. hydrophila.
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Judul: Evaluasi Penambahan Ragi Limbah Produksi Bir dalam Pakan terhadap Kinerja Pertumbuhan dan Daya Tahan Ikan Lele Clarias sp. akibat Infeksi Aeromonas hydrophila
Abstrak: The purpose of the study was to test on field-scale the addition of brewer’s yeast Saccharomyces cerevisiae which was considered as brewery by-product in feed on growth performance and immunity of catfish against the infection of Aeromonas hydrophila. Catfish weighed 2.09 ± 0.01 g with average length of 6.42 ± 0.07 cm were stocked in tarpaulin ponds 200 x 200 x 80 cm3 as much as 1.000 fish/pond with 2 treatments and 3 replications. Fish were fed commercial feed without brewer’s yeast addition (K), and brewer’s yeast added feed (RB) for 30 days and the growth response were observed. Fish were challenged in aquariums 60 x 30 x 25 cm3 using 3 treatments and 3 replications which consisted of K- (PBS injected fish), K+ (A. hydrophila injected fish), and RB (A. hydrophila injected fish). After injection, fish were fed K feed for 10 days and the mortality rate were observed. The results showed that feeding with RB feed increased the growth rate of the fish and decreased the feed conversion ratio. Cost analysis showed that RB treatment could decrease feed production cost toRp 33917 from Rp 39418 (control). Fish immunity were increased with increasing total blood leukocytes, suppressed A. hydrophila infection indicated by lighter clinical symptoms showed, and suppressed mortality rate (71.67%) compared to K+ (95.00%).
Keyword: Saccharomyces cerevisiae., growth, endurance, catfish, brewer's yeast, Aeromonas hydrophila

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology