Judul: Pemakaian hasil fermentasi daun mata lele Azolla sp. sebagai bahan baku pakan ikan nila Oreochromis sp.
Abstrak: The good nutritional content of Azolla sp. shows that this leaves has the potential to be utilized as an alternative feed ingredient for fish. The objective of this experiment was to find an alternative high quality herbal ingredient for tilapia feed and to assess the most optimal dosage of azolla leaves fermented with Trichoderma harzianum in tilapia feed. The experiment consisted of two stages, the first stage was aimed at finding the best fermentation period that result in the best nutritional quality of azolla leaves, whereas the second stage of experiment was performed to evaluate the best inclusion level of fermented azolla leaves in tilapia feed by assessing growth performance. Tilapia with an average body weight of 10,59 ± 1,29 g was used as the experimental animal. Experimental diets were obtained by repelleting commercial feed with different level of fermented azolla leaves, namely treatment 0 % (A/control), 30 % (B), 60 % (C), and 90 % (D). Fish was cultured for 40 days during which the growth of the fish was observed, and feces was collected for 15 days for digestibility test. The results showed that two days fermentation period resulted in the best improvement of azolla leaves nutritional content with reduction in fiber content of 37,19 % and protein content enhancement of 38,65 %. Feed consumption of treatment B was not much different from control, but different than treatment C and D. This trend was also observed in feed palatability, daily growth rate, feed efficiency and protein digestibility. The result of this experiment shows that fermentation may improve azolla leaves nutritional value with the best inclusion level of 30 %.
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Judul: The use of hydrolyzed Azolla pinnata to substitute soybean meal in juvenile Nile tilapia (Oreochromis niloticus) diet
Abstrak: Nile tilapia, Oreochromis niloticus is one of the most cultured fish species in tropical and subtropical countries of the world. It provides one of the main sources of income and animal protein throughout the world. Because of their faster growth rate, tolerance to harsh environment and ease culture technique, tilapia offers the possibility of commercial and home-grown protein. However, feed is the key cost variable in tilapia culture, which accounts 80% of total production cost. The high feed cost is mostly caused by the high protein content in the diet and the high price of protein. Soybean is one of the most utilized plant protein sources in aquaculture feed. However due to its cost, availability and competitiveness with other human use, alternative plant protein sources were explored which is Azolla pinnata. Azolla pinnata is a cheap, sufficient nutritional value for protein lipid carbohydrate vitamin and mineral, locally available and affordable to most fish farmers. Nutritional quality of Azolla pinnata can be improved by fermentation methods or by hydrolysis using sheep rumen liquor. This contains protease, lipase, amylase, and cellulase enzymes. This study aimed to use hydrolyzed aquatic macrophyte Azolla pinnata meal to substitute soybean meal (SBM) in the diet of Nile tilapia (O.niloticus). Where, enhancement of nutritional composition of azolla pinnata, hydrolyzed Azolla pinnata digestibility and inclusion level of hydrolyzed Azolla pinnata in Nile tilapia diet for growth performance was evaluated. In the nutritional composition of the Azolla pinata meal after hydrolysis with rumen digestive fluid showed satisfactory increase of nutritional contents including protein content 34.03%, lipid 5.56%, and reduced crude fiber up to 7.80%. Morever chromic oxide at 0.5% was mixed as the diet inert markers. The fish feces were collected from six aquariums (50×40×30cm3) during 21 days. The reference diet showed high digestibility of dry matter, protein and energy including 88.1%, 92.8% and 91.2% respectively, for those of test diet with 34.1% 50.3% and 32.3% respectively for digestibility study. Concerning the growth study, five test diets of 30% crude protein were formulated by different substitution level of soybean meal by hydrolyzed Azolla pinnata meal including diets A, B, C, D, E (0%, 10%, 20%, 30% and 40% of hydrolyzed Azolla pinnata meal respectively). The experiment was conducted during 57 days where 10 fish of 8-10g were stocked in 15 aquariums (50×40×30cm3). Fish were fed two times daily to apparent satiation. At the end of this study, results showed that hydrolyzed Azolla pinnata meal can be added to Nile tilapia feed up to 30% without affecting fish growth performance.
Keyword: Digestibility, growth, hydrolyzed Azolla pinnata, Oreochromis niloticus

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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