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: Application of probiotic, prebiotic and synbiotic to enchance the immune response of shrimp Litopenaeus vannamei against Vibrio harveyi infection
Abstrak: Probiotic, prebiotic and synbiotic are now widely used in aquaculture and showed their capability in controlling the bacterial disease. The aim of this study was to the test the effectiveness of probiotic, prebiotic and synbiotic in enhancing the immune response of shrimp againts Vibrio harveyi infection. This research comprised of 5 treatments, namely: control P0(+), control P0(-), 1% probiotic (P1), 2% prebiotic (P2) and synbiotic (1% probiotic+2% prebiotic: P3). Probiotic SKT-b (dose 106 CFU/ml) was supplemented into bacterial feed. Prebiotic used in this study was oligosaccharides derived from sweet potato varietie of Sukuh (2% of the feed weight). Shrimp used in this study was Litopenaeus vannamei larvae (±3.5 g in weight). Shrimp were cultured aquaria 60x35x30 cm3 filled with 40 L seawater for 28 days. Immune response parameters observed including total hemocyte, phagocytic activity and phenoloxidase activity (PO). Each parameter was observed 9 times, i.e at 0, 7 and 14 day of culture and after a challenge test, i.e at the 6, 12, 24, 72, 120 and 168 hours post infection. Post-test results showed that the highest survival P3 treatment (100%), followed by P1(90%), P2(83%), and P0(+)(60%) showed by respectively. The results of the immune response observed during the study showed the highest in P3 (total hemocyte 3,36±0,05- 9,32±0,05x106 cells/ml, phagocytic activity of 16,48±0,14-77,55±0,22% and PO activity 0,128±0,03-0,591±0,01) and the lowest was P0(+) (total hemocyte 3,15±0,16-4,53±0,33x106 cell/ml; phagocytic activity 10,15±0,10-20,78±0,34% and PO activity 0,128±0,03-0,181±0,03). From this study, we concluded that the addition synbiotic into the feed can improve the immune response of shrimp better than the other treatments.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular