Judul: Selection of probiotic bacteria for controlling vibriosis on tiger grouper (Epinephelus fuscoguttatus)
Abstrak: Vibriosis is a bacterial disease affecting farmed fish including grouper. Disease control usually uses antibiotic but can lead to ecological inbalance and antibioticresistant pathogens. The use of probiotic bacteria is one of the methods in aquaculture that is used to control infectious diseases. The aims of this study were to obtain and isolate pathogenic Vibrio in the tiger grouper, to select bacterial probiotic candidates in controlling vibriosis, to evaluate efficacy of probiotic bacterial administration in controlling vibriosis in tiger grouper fry, and to evaluate probiotic bacterial candidates in enhancing immune responses. The first step was isolation and characterization of pathogenic bacteria as causative agent of vibriosis on grouper. Secondly, selection of probiotic candidate bacteria was conducted from the coral reef and tiger grouper fish farming environment including isolation of probiotic candidates, selection of probiotic candidates using inhibition test, co-culture method, and pathogenicity test of selected probiotic candidates. The third and fourth steps were administration of probiotic candidate bacteria on tiger grouper fry and juvenile, respectively, on feed for 28 days, and challenge test was performed at day-29. The result indicated that V6 isolate was the most pathogenic among isolates. Moreover, from 124 isolates, based on selection of probiotic candidates bacteria using inhibition zone and co-culture methods, there were found four potential isolates namely K7, K8, K21, T41, and K15, K55, K68, T36, respectively. Four isolates, namely K7, K8, T36 and T41, had high survival rate of fish in pathogenicity test. Furthermore, T36 isolate may decrease pathogenic Vibrio population, increase immune response, survival rate and growth rate of tiger grouper. According to gene sequencing analysis using 16S-rRNA, V6 dan T36 were Vibrio parahaemolyticus and Bacillus cereus, respectively.
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Judul: Study of Supplementation of Dietary Probiotic, Prebiotic, and Synbiotic to Precaution Vibriosis in Polkadot Grouper (Cromileptes altivelis).
Abstrak: Vibriosis was a major bacterial diseases in grouper fingerlings and very harmful. One of the diseases that often attack the humpback grouper fish was bacterium V. alginolyticus. V. alginolyticus attack on marine fish could reach up to 100% mortality. Application of probiotics, prebiotics and synbiotic through feed was expected to be one of the ways to boost the immune system of the fish. This study aimed to assess the effect of probiotics, prebiotics, and synbiotic on humpback grouper feed for vibriosis infection prevention through observation of immune response, survival and growth performance. The research covers the preparation stage and the media container maintenance, preparation of probiotic, preparation of prebiotic, feed preparation, testing probiotic, prebiotic, and synbiotic through the feed. There were five tests in the commission of the feed, feeding without probiotic, prebiotic, and synbiotic and PBS injected, feeding without probiotic, prebiotic, and synbiotic and infected V. alginolyticus, feeding of 1% with probiotic and infected V. alginolyticus, feeding of 2% prebiotic and infected V. alginolyticus, feeding with probiotics 1% and prebiotics 2 % and infected V. alginolyticus. Challenge test was injecting V. alginolyticus intramuscularly. Testing the performance of growth at the end of treatment probiotic, prebiotic, and synbiotic by measuring the daily growth rate and feed conversion ratio. Immune response testing was also conducted by measuring the total erythrocytes, total leukocytes, hemoglobin, hematocrit, respiratory burst activity, phagocytic activity and total bacteria. The characterization of probiotic was conducted by Cowan. The result showed that the bacterium was Bacillus sp. The result of oligosaccharide extraction (TPT 5%) used in this study consist of 1.115% inulin; 1.015% FOS and 1.488% GOS. Feeding with the addition of probiotic, prebiotic, and synbiotic for thirty days can increase the survival rate and growth performance (DGR and FCR) and resistance to disease. Overall immune response results obtained in this study showed significant improvement between the administration of probiotics, prebiotics, and synbiotic to control.
Keyword: humpback grouper, prebiotic, probiotic, synbiotic, Vibrio alginolyticus

Judul: Analisis keamanan konstruksi fungsi hash berbasis sandi blok kunci simetrik (Kajian Teoritik)
Abstrak: Hash function is used to secure the integrity and authenticity of a massege, so that the message is save. The message which will be secured, will be attached to hash/message digest/digital signature value fro, the message. A secure hash function is the one which has pre-image resistance, 2nd pre-image resistance and collision resistance. Hash function has been classified into hash keyed function (Message Authentication Codes/MAC) and unkeyed (Modification Detection Codes/MDC)
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