Judul: Application of Bacillus cereus BR2, Honey, and the combination of both for prevention of Streptococcus agalactiae infection in saline nile tilapia (Oreochromis niloticus)
Abstrak: Ikan nila merupakan komoditas unggulan yang dibudidayakan secara intensif dan berpeluang terserang penyakit Streptococcus agalactiae. Upaya pencegahan yang dapat dilakukan untuk mengurangi dampak serangan bakteri S. agalactiae adalah dengan pakan suplementasi menggunakan probiotik, prebiotik, dan sinbiotik. Penelitian ini bertujuan untuk menguji pengaruh pemberian probiotik Bacillus cereus BR2, prebiotik madu randu, dan gabungan keduanya melalui pakan untuk pencegahan infeksi S. agalactiae. Penelitian ini terdiri atas lima perlakuan dan tiga ulangan yaitu A (B. cereus BR2 109 CFU mL-1 1%), B (madu randu 1%), C (B. cereus BR2 109 CFU mL-1 1% + madu randu 1%), K+ dan K- (tanpa suplementasi). Ikan uji yang digunakan adalah ikan nila nirwana 3 dengan bobot rata-rata 15,13±1,74 g. Ikan diaklimatisasi terlebih dahulu ke air payau secara bertahap hingga salinitas 10 ppt dalam akuarium berukuran 60×30×40 cm3 dengan kepadatan 10 ekor per akuarium (450 ekor m-3 ). Selama 30 hari pemeliharaan, ikan diberi pakan komersil yang telah disuplementasi sebanyak 3 kali sehari sekenyangkenyangnya. Hasil penelitian menunjukkan bahwa tingkat kelangsungan hidup, kinerja pertumbuhan, dan respon imun ikan nila salin yang diberi perlakuan suplementasi pakan probiotik B. cereus BR2 dan prebiotik madu randu lebih baik dan berbeda nyata (P<0,05) dibandingkan perlakuan kontrol. Pemberian sinbiotik B. cereus BR2 dan madu melalui suplementasi pakan dapat meningkatkan kinerja pertumbuhan dan respons imun ikan ikan nila salin., Tilapia is the main commodity that is cultivated intensively and has the potential to be infected by Streptococcus agalactiae. Prevention efforts that can be done to reduce the impact of S. agalactiae attack are by supplementing feed using probiotics, prebiotics, and synbiotics. This study aimed to examine the effect of giving Bacillus cereus BR2 probiotic, honey prebiotic, and a combination of both through the feed for the prevention of S. agalactiae infection. This study consisted of five treatments and three replications, namely A (B. cereus BR2 109 CFU mL-1 1%), B (kapok honey 1%), C (B. cereus BR2 109 CFU mL-1 1% + kapok honey 1 %), K+ and K- (without supplementation). The test fish used were nile tilapia with an average weight of 15.13±1.74 g. The fish were first acclimatized to brackish water gradually to 10 ppt. salinity in an aquarium measuring 60×30×40 cm9 with a density of 10 fish per aquarium (450 fish m-3 ). During the 30 days of rearing, the fish were given commercial feed which had been supplemented 3 times a day as full as possible. The results showed that the survival rate, growth performance, and immune response of saline tilapia which were treated with B. cereus BR2 probiotic feed supplementation and prebiotic kapok honey were better and significantly different (P<0.05) than the control treatment. The application of B. cereus BR2 and kapok honey synbiotic through feed supplementation can improve growth performance and immune response of saline tilapia.
Keyword: Bacillus cereus BR2, honey, Streptococcus agalactiae, tilapia, ikan nila salin, madu

Judul: Growth Performance, Immune Response, and Resistance of Nile Tilapia Fed Bacillus sp. NP5 Paraprobiotic and infected by Streptococcus agalactiae
Abstrak: Penelitian ini bertujuan untuk mengevaluasi efektivitas pemberian paraprobiotik Bacillus sp. NP5 yang ditambahkan melalui pakan pada kinerja pertumbuhan, respons imun, dan resistansi ikan nila terhadap infeksi Streptococcus agalactiae. Penelitian ini menggunakan rancangan acak rengkap yang terdiri dari 3 perlakuan 5 ulangan, penambahan probiotik 1%, penambahan paraprobiotik 1% dan tanpa penambahan probiotik atau paraprobiotik (kontrol). Ikan perlakuan dipelihara selama 30 hari, pada hari ke 31, uji tantang dengan S. agalactiae (107 CFU ml-1) yang diinjeksikan melalui intraperitoneal kecuali perlakuan kontrol negatif yang diinjeksi dengan PBS. Hasil penelitian setelah 30 hari pemberian probiotik dan paraprobiotik Bacillus sp. NP5 menunjukkan kinerja pertumbuhan dan respons imun yang meningkat signifikan (P<0.05) dibandingkan dengan kontrol. Pasca uji tantang, peningkatan respons imun pada perlakuan probiotik dan paraprobiotik Bacillus sp. NP5 menunjukkan tingkat kelangsungan hidup yang lebih tinggi (P<0.05) dibandingkan kontrol positif pasca uji tantang dengan S. agalactiae. Pemberian probiotik dan paraprobiotik Bacillus sp. NP5 melalui pakan efektif dalam meningkatkan kinerja pertumbuhan, respons imun, dan resistansi ikan nila terhadap infeksi Streptococcus agalactiae., The aim of this study was to evaluate the effectiveness of paraprobiotic Bacillus sp. NP5 administration through commercial feed on the growth performances, immune responses, and resistance of nile tilapia against Streptococcus agalactiae infection. This study used a completely randomized design, which consisted of three treatments with five repetitions, that were 1% (v/w) addition of probiotic, 1% (v/w) addition of paraprobiotic, and no addition of probiotic or paraprobiotic (control). The experimental fish were reared for 30 days and on day 31, the fish was challenge tested with S. agalactiae (107 CFU ml-1) injected by intraperitoneal route, unless the negative control was injected with PBS. The results of this study showed significantly improved growth performances and immune responses (P<0.05), compared to the control group after 30 days of probiotic and paraprobiotic Bacillus sp. NP5 administered. After challenge tested, the increased of immune responses in the probiotic and paraprobiotic of Bacillus sp. NP5 showed a higher survival rate (P<0.05), than positive control after callenge tested with S. agalactiae. Administration of probiotic and paraprobiotic Bacillus sp. NP5 through the commercial feed were effective in increase the growth performances, immune responses, and resistance of nile tilapia against S. agalactiae infection.
Keyword: Bacillus sp. NP5, nile tilapia, paraprobiotic, Streptococcus agalactiae

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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