Judul: Study of Biofloc Technology for Controlling  Streptococcus agalactiae in Cultivated Tilapia Oreochromis niloticus
Abstrak: Sistem intensifikasi yang diterapkan dalam budidaya ikan nila saat ini semakin meningkat. Namun, seringkali ditemukan permasalahan pada teknologi budidaya dan infeksi patogen terutama bakteri dan virus penyebab penyakit. Salah satu jenis bakteri penyakit yang sering menyerang budidaya ikan nila adalah Streptococcus agalactiae. Untuk mengatasi masalah ini, peningkatan teknologi budidaya sangat penting untuk dapat memodulasi resistensi penyakit. Teknologi bioflok (BFT) saat ini terus disempurnakan karena kemampuannya dalam mencegah infeksi S. agalactiae. Efektivitas BFT telah dibuktikan dan dievaluasi secara luas oleh banyak penelitian dalam meningkatkan ketahanan respons imun dan kinerja pertumbuhan ikan nila. Tujuan dari studi literatur yangdilakukan adalah untuk merangkum dan membandingkan pengaruh penerapan BFT pada perlakuan dan kondisi yang berbeda terhadap respons imun ikan nila untuk mencegah infeksi S. agalactiae. Penelitian ini menggunakan kajian antar pustaka dan metode yang telah dipublikasikan dalam 20 tahun terakhir. BFT tidak hanya meningkatkan respons imun ikan nila budidaya, tetapi juga dapat memodulasi mikrobiota usus, meningkatkan ketahanan terhadap penyakit, meningkatkan pertumbuhan, dan menjaga kualitas air. BFT mampu meningkatkan respons imun non-spesifik sehingga mampu menurunkan angka kematian ikan nila yang disebabkan oleh bakteri S. agalactiae., Intensification system applied in tilapia cultivation is increasing tremendously. However, there are often problems encountered with cultivation technology and pathogenic infections especially bacterial and viral that cause disease. One species of bacterial disease that often attacks tilapia fish farming is Streptococcus agalactiae. To overcome this problem, an improved cultivation technology is crucial to be able to modulate the disease resistance. Biofloc technology (BFT) is currently continuing to be refined due to its ability to prevent S. agalactiae infection. The BFT effectiveness has been widely proven and evaluated by many studies in improving the immune response survival and growth performance of tilapia. The aim of the literatures study carried out was to summarize and compare the effect of the application of BFT in different treatments and conditions on the immune response of tilapia to prevent S. agalactiae infection. The study uses an inter library reviews and methods that has been published in the last 20 years. BFT is not only improve the immune response of farmed tilapia, but can also modulate the gut microbiota, increase the disease resistance, increase the growth, and maintain the water quality. BFT is able to increase non-specific immune responses so that it can reduce the death rate of tilapia caused by S. agalactiae bacteria.
Keyword: ikan nila, respons imun, immune response, nile tilapia, teknologi bioflok, S. agalactiae, studi pustaka, biofloc technology, literature study

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: 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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