Judul: Evaluation of quality and digestibility of cassava peel, rubber seed, copra, cottonseed, and palm kernel meal fermented by Saccharomyces cerevisiae in juvenile of nile tilapia Oreochromis niloticus.
Abstrak: Feed becomes the most expensive factor in freshwater aquaculture production. It often costs from 45% to 85% of total variable expensis, depending on its intensity of culture operation. The high price is caused by materials which used in this operation. The materials availability still rely on imports such as fish meal, soybean meal, and flour. This makes price of feedstuff is not competitive. Therefore, an alternative local’s feedstuffs which could potentially reduce or even replace imported feedstuff composition in diets is needed. However, the low quality of local’s feedstuffs nutrition make it difficult to developed. This low quality caused by high crude fiber content and the presence of anti-nutritional substances factor, so it needs to be processed first by fermentation methods. This study used five treatments, two factors, and one replicates. Fish used in this study were juvenile of nile tilapia Oreochromis niloticus which has weight about 16,26±2,43 grams. Diets given at satiation, three times a day. The feedstuffs used are cassava peel, rubber seed, cottonseed, copra, and (Palm Kernel Meal, PKM). The result of this study showed some enhancements in fish content. The fermentation by Saccharomyces cerevisiae can increase fish (test material) protein around 16,85%-31,11%, decrease crude fiber around 2,46%-31,65%, increase protein digestibility around 0,25%-11,7%, increase digestibility of energy around 4,29%-11,17% (except for digestibilty in the cassava peel) and also increase the digestibility of feedstuffs around 1,37%-61,19% in juvenile of nile tilapia O. niloticus.
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Judul: Improvement of corn quality using physical mechanism and fermentation with Rhizopus oligosporus and its utilization in tilapia (Oreochromis niloticus) feed
Abstrak: Growth performance of fish is highly influenced by the quality of feed, which is determined dominantly by the quality of feedstuff. The research was conducted to evaluate both physical mechanism and fermentation with Rhizopus oligosporus on corn quality and utilization of fermented corn meal by R. oligosporus in feed on the growth of tilapia Oreochromis niloticus. The research containing three steps. First step was using physical mechanism there were soaked, boiled, steamed, and control. The best result from the first step was used in second step, fermented with R. oligosporus. The result was used in third step for biological test. Ten tilapia with 5.0±0.14 g/fish initial body weight were used and stocked in each of fifteen aquaria. The aquaria were equipped with water heater and recirculation system. This research used a complete randomized design with five treatments (0%, 5%, 10%, 15%, and 20% of fermented corn meal) and three replications. The parameters were specific growth rate, feed consumption, feed conversion ratio, protein efficiency ratio, protein retention, fat retention, phosphorus and calcium retention, hepatosomatic index, survival rate, the digestibility of total feed, protein, phosphorus, and calcium. The result showed at first step that steaming gave the best result to reducing phytic acid and increasing digestibility, second step showed fermentation could increasing phosphorus and calcium, protein content, reducing phytic acid and crude fiber fraction also increasing corn digestibility. The third step result showed that 10-15% fermented corn meal in feed gave the best specific growth rate, feed conversion ratio, protein efficiency ratio, protein retention, and protein digestibility (P<0.05). Fat retention, hepatosomatic index, and survival rate were not significantly different (P>0.05) among treatments. The feed up to 15% fermented corn meal level gave the best growth for tilapia fingerling.
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Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix