Judul: The frequency effect of synbiotic supplementation diet to control the co-infection disease of Infectious Myonecrosis Virus and Vibrio harveyi
Abstrak: One of the obstacles in intensive shrimp culture is the high frequency of disease. The diseases that most often attack are bacterial, viral and infection by bacterial and viral at the same time (co-infection). Co-infection disease can accelerate and increase mortality. One of the alternative to prevent the diseases is synbiotics, because synbiotics could increase the shrimp immune response and resistance to diseases. This study aimed to evaluated the frequency effect of synbiotic supplementation diet to control the co-infection disease of IMNV and V. harveyi. The frequencies applied in this study were daily, once in three days and once a week supplementation. The synbiotics used in this study is the combination between the probiotics SKT-b and prebiotic is the derivate of oligosaccharide from sweet potato starch (Ipomoea batatas L). Several stages of this study consisted of prebiotic preparation (making the sweet potato starch, oligosaccharide extraction with ethanol 70%, the determination of total dissolved solid and oligosaccharide test with HPLC), probiotic preparation, IMNV stock preparation and V. harveyi preparation, 1 dosage synbiotics (1% probiotic with 2 % prebiotic) in vivo test during 30 days and challenged test. The growth performance were the daily growth rate and feed conversion ratio. The number of bacteria in shrimp intestine observed at the end of synbiotics treatment consisted of the total viable bacterial count, presumptive vibrio counts and the presumptive SKT-bR counts. Immune responses observed before and after challenge test were total hemocyte count, the numbers of hemocytes (hyaline cells and granular cells), phenoloxidase activity and respiratory burst activity. Shrimp resistance observed was the shrimp survival against co-infection by IMNV and V. harveyi for seven days. PCR test using Nugen IMNV diagnostic kits for IMNV confirmation and streak plate method on TCBS containing rif media for V. harveyi confirmation. The result of oligosaccharide extraction with 5% TPT used in this study consist of 1,115% inulin; 1,015% FOS and 1,488% GOS. Supplementation of synbiotics diet during 30 days were increase the number of bacteria in shrimp intestine and improve growth performance (LPH and FCR) and shrimp resistance against co-infestion IMNV and V. harveyi. Synbiotics treatment significantly increase THC value and PO activity than controls (before challenge test). Generally, daily supplementation of synbiotics showed better resistance against co-infection IMNV and V. harveyi and better growth performance than control. Daily supplementation of synbiotics given the best result in LPH was 8,12±0,12% and FCR was 1,11±0,08. Total hemocyte count value was 6,40x106±0,85 cell/ml and phenoloxidase was 1,07±0,15. Moreover, daily supplementation of synbiotics given the best shrimp resistance against co-infection by IMNV and V. harveyi with the survival value was 93,33±5,77% compared with positive control was 46,67±11,57%.
Keyword: Co-infection, IMNV, Litopenaeus vannamei, Synbiotic, Vibrio harveyi

Judul: Aplikasi Sinbiotik pada Udang Vaname Litopenaeus vanammei: Resistensi terhadap Infectious Myonecrosis Virus dan Performa Pertumbuhan
Abstrak: Outbreaks of Infectious Myonecrosis (IMN) attack white shrimp farming in Indonesia and caused death up to 70%. Many studies have shown efficacy of probiotics in improving the resistance of shrimp or fish against disease by suppressing pathogens, while enhancing immunity and or improving water quality. Application prebiotics also has shown a variety of benefits to the aquatic animal. However, the combination of probiotics with prebiotics (synbiotics) showed better results than when it is applied separately. This study aimed to evaluate the potential of synbiotics from SKT-b bacteria and oligosaccharides-extracted from sweet potatoes, in increasing both white shrimp resistance to IMN and their growth performance. The experiment was conducted in Mei-September 2012, held at the Fish Health Laboratory, Faculty of Fisheries and Marine Sciences and the Diploma Programme, Bogor Agricultural University. This study includes the preparation of a prebiotic (sweet potato-extrac preparation and analyzes of oligosaccharides), preparation of probiotic bacteria (SKT-b bacteria growth), in vitro and in vivo tests. In vitro study tested the combination of prebiotics dose 0, 1, 2 and 3% and probiotics 107, 108, 109, 1010 cfu ml-1, that result the best growth of probiotic bacteria. In in vivo test, the white shrimp was given a feed in which probiotics (1010 cfu g feed-1) with various doses of prebiotics (0, 1, 2, and 3%) added, for 30 days. Measurement parameters to test the growth performance is conducted at the end of treatment, including specific growth rate, feed efficiency, retention of nutrients (protein and lipid) and the activity of digestive enzymes (protease and amylase). On challenge their resistance to IMN, shrimp was infected with IMN virus (IMNV) through injection and was observed for 10 days. Parameters observation includes survival, clinical symptoms, and immune parameters (total hemocyte [THC] and phenoloxidase [PO] activities). The ethanol extract of sweet potato used in this study contains three types of oligosaccharide-which are maltoheptaosa, sucrose, and raffinose-with the total concentration of oligosaccharides that reached 64,86%. SKT-b bacteria reached its optimal growth after 16 hours which was 5,9 x1010 cfu ml-1. The results of in vitro assays showed that the addition of prebiotic in culture medium can increase the growth of SKT-b bacteria which was positively correlated with the escalation of the dose of prebiotics and the concentrations of inoculants. The most optimal combination of prebiotics and probiotics was obtained from the addition of 3% of prebiotics and 1010 cfu ml-1 of SKT-b bacteria inoculant. In in vivo tests, the synbiotic feeding treatment (Pro+Pre) for 30 days increased shrimp survival and lowered its infection rates to IMNV, along with the increasing doses of prebiotics. This is because the increased of shrimp’s immunity after the synbiotics treatment was given. Pro+Pre 2% and Pro+Pre 3% treatment can increase THC of white shrimp to two times greater than THC of the shrimp control in the beginning of the observation. The decrease the amount of THC in both treatments after infection IMNV indicates a rapid reaction to the infection. IMNV infection caused the increase of PO activities in the shrimp in all treatments until the end of the observation. The highest PO
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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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