Judul: Analysis of the Effect of Bacillus sp. Probiotic Application for Controlling Vibrio spp. Bacterial Population in Vannamei Shrimp (Litopenaeus vannamei) Cultivation.
Abstrak: Bakteri Vibrio spp. merupakan salah satu jenis bakteri patogen yang sering ditemukan di lingkungan perairan, seperti pada budidaya udang. Infeksi Vibrio spp. mampu menyebabkan beberapa penyakit pada udang seperti vibriosis, Acute Hepatopancreatic Necrosis Disease (AHPND), dan feses putih. Pengendalian jumlah populasi dan infeksi oleh Vibrio spp. dalam budidaya udang dengan penggunaan probiotik Bacillus sp. pada pakan udang. Bakteri Bacillus sp. memiliki kemampuan anti quorum sensing dengan mengganggu acyl homoserine lactones (AHL), sehingga AHL Vibrio spp. tidak mencapai kondisi kuorum. Penelitian ini bertujuan menganalisis pengaruh aplikasi probiotik Bacillus sp. untuk pengendalian populasi bakteri Vibrio spp. pada budidaya udang vaname. Penelitian dilakukan hingga Day of Culture (DOC) 120 pada 6 kolam tambak terletak di PT. Sentra Budidaya Biotek, Kabupaten Sumbawa Barat, Nusa Tenggara Barat. Metode yang digunakan terdiri dari persiapan tambak, aklimatisasi benur, perbanyakan dan aplikasi probiotik Bacillus sp., Pemeriksaan kualitas air, isolasi dan perhitungan bakteri Vibrio spp., uji histopatologi hepatopankreas udang, sampling udang, dan panen udang. Aplikasi probiotik Bacillus sp. memberikan dampak positif terhadap pengendalian populasi bakteri Vibrio spp., kualitas air tambak, uji histopatologi hepatopankreas udang, dan hasil panen udang. Hal ini ditunjukkan dengan populasi Vibrio spp. dibawah ambang batas, terkendalinya kualitas air, terkendalinya infeksi dari Vibrio spp. pada hepatopankreas udang dan jumlah produksi udang mencapai target., Vibrio spp. are a type of pathogenic bacteria commonly found in aquatic environments, such as in shrimp pond. Infections by Vibrio spp. can lead to several shrimp diseases such as vibriosis, Acute Hepatopancreatic Necrosis Disease (AHPND), and white feces syndrome. Controlling the population and infections of Vibrio spp. in shrimp pond can be achieved through the use of Bacillus sp. in shrimp feed. Bacillus sp. have anti-quorum sensing abilities by disrupting acyl homoserine lactones (AHL), preventing Vibrio spp. from reaching quorum conditions. This study aims to analyze the effects of Bacillus sp. controlling the population of Vibrio spp. in vannamei shrimp pond. The research was conducted until Day of Culture (DOC) 120 in 6 ponds located at PT. Sentra Budidaya Biotek, West Sumbawa, West Nusa Tenggara. The methods included pond preparation, shrimp acclimatization, Bacillus sp. culture and application, water quality assessment, isolation and quantification of Vibrio spp., histopathological examination of hepatopancreas, shrimp sampling, and harvest. The application of Bacillus sp. showed positive impacts in suppressing Vibrio spp. populations, maintaining pond water quality, reducing Vibrio spp. infections in shrimp hepatopancreas, and shrimp production. This was evidenced by Vibrio spp. populations staying below threshold limits, controlled water quality, controlled infections from Vibrio spp. in shrimp hepatopancreas, and achieving the targeted shrimp production.
Keyword: Aplikasi, Litopenaeus vannamei, anti-quorum sensing, Bacillus  sp., Vibrio spp.

Judul: Application of Multispesies Probiotics, Prebiotics and Synbiotics for the Prevention of Vibriosis in Vannamei Shrimp Litopenaeus vannamei
Abstrak: Salah satu masalah dalam budidaya udang adalah serangan penyakit vibriosis akibat infeksi bakteri Vibrio parahaemolyticus. Alternatif preventif dan ramah lingkungan yang dapat ditawarkan yaitu menggunakan probiotik, prebiotik dan sinbiotik. Penelitian ini bertujuan untuk menguji pengaruh pemberian multispesies probiotik Lactobacillus plantarum dan Bacillus cereus, prebiotik mannanoligosakarida serta sinbiotik terhadap kinerja pertumbuhan dan respons imun udang vaname yang diinfeksi bakteri V. parahaemolyticus. Penelitian ini terdiri atas empat perlakuan pada uji suplementasi dan lima perlakuan pada uji tantang, yaitu kontrol (tanpa suplementasi), suplementasi multispesies probiotik L. plantarum dan B. cereus, prebiotik MOS serta sinbiotik. Udang vaname dengan bobot rata-rata 0,55±0,01 g dipelihara dengan padat tebar 15 ekor/akuarium. Udang diberi pakan komersial yang telah diperkaya dengan multispesies probiotik L. plantarum dan B. cereus, prebiotik MOS serta sinbiotik selama 40 hari, kemudian diuji tantang dengan bakteri V. parahaemolyticus. Parameter yang diamati selama penelitian meliputi tingkat kelangsungan hidup, laju pertumbuhan spesifik, rasio konversi pakan, total haemocyte count, differential haemocyte count, aktivitas fagositik, aktivitas respiratory burst, dan aktivitas phenoloxidase. Hasil penelitian menunjukkan bahwa pemberian multispesies probiotik L. plantarum dan B. cereus, prebiotik MOS serta sinbiotik dapat meningkatkan kinerja pertumbuhan dan respons imun udang vaname yang diinfeksi V. parahaemolyticus dengan hasil terbaik pada perlakuan multispesies probiotik dan sinbiotik., One of the problems in shrimp farming is the attack of vibriosis disease due to infection with Vibrio parahaemolyticus bacteria. Preventive and environmentally friendly alternatives that can be offered are using probiotics, prebiotics and synbiotics. This study aimed to examine the effect of multispecies probiotics Lactobacillus plantarum and Bacillus cereus, mannanoligosaccharide prebiotics and synbiotics on growth performance and immune response of white vaname shrimp infected with V. parahaemolyticus bacteria. This study consisted of four treatments in the supplementation test and five treatments in the challenge test, namely control (without supplementation), multispecies supplementation of probiotics L. plantarum and B. cereus, MOS prebiotics and synbiotics. Vannamei shrimp with an average weight of 0.55±0.01 g were reared at a stocking density of 15 fish/aquarium. Shrimp were fed commercial feed enriched with multispecies probiotic L. plantarum and B. cereus, MOS prebiotic and synbiotic for 40 days, then challenged with V. parahaemolyticus. Parameters observed during the study included survival rate, specific growth rate, feed conversion ratio, total haemocyte count, differential haemocyte count, phagocytic activity, respiratory burst activity, and phenoloxidase activity. The results showed that the administration of multispecies probiotics L. plantarum and B. cereus, MOS prebiotics and synbiotics could improve the growth performance and immune response of white vaname shrimp infected with V. parahaemolyticus with the best results in the multispecies treatment of probiotics and synbiotics.
Keyword: Bacillus cereus, Lactobacillus plantarum, Litopenaeus vannamei, Mannanoligosaccharide (MOS), Vibrio parahaemolyticus

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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