Judul: Effort of survival rate improvement of climbing perch anabas testudineus bloch larvae through study on digestive system ontogeny, HUFA biosynthesis ability and essential fatty acid enrichment
Abstrak: Climbing perch Anabas testudineus (Bloch) is commercially valuable fish species and representing a great of interest for aquaculture in Kalimantan, Indonesia. However, limited success on larval rearing of the fish has been obtained. Thus, the aim of the study was to increase survival rate of the larvae through evaluations on: ontogeny of digestive system, ability of HUFA biosynthesis, and enrichment of essential fatty acid. Development of digestive system was evaluated in larvae reared from hatching to 30 days after hatching using histological and morphological methods, and biochemical techniques. PUFA to HUFA biosynthesis ability was evaluated in fish using analysis of gene expression encoding enzymes involved in HUFA biosynthesis, and fatty acid profile. Development of the digestive tract in climbing perch followed the general pattern described for other species. At hatching (D0), it consisted of an undifferentiated straight tube laying dorsally to the yolk sac. At first feeding (D2), the digestive tract was fully differentiated into buccopharynx, esophagus, intestine and rectum with opened mouth and anus, and almost digestive enzymes were detected. The activities of all the enzymes remained stable from D25 onwards, coinciding with the formation of pyloric caecum. The enzymatic equipment of the larvae was completely efficient up to D25 and since then formulated feed could be offered. Moreover, the results showed that the fatty acid elongase and desaturase genes expression level was increased in the 12-day larvae fed on corn and the candle nut oil-enriched rotifers. This suggested that the elongase and desaturase enzymes were involved in HUFA biosynthesis. Results also indicated that the larvae fed by enriched rotifer with vegetable oil emulsions had higher survival rate than that of fed by non-enriched in control treatment. The highest survival rate of larvae was obtained in treatment D with ratio 1:1 of the corn and candle nut oils. In this treatment, concentration of docosahexaenoic acid (DHA; 10.33%) and arachidonic acid (ARA; 6.20%) was higher compared to the other treatments. It is most likely that DHA and ARA play important role on survival of the larvae. Therefore, the corn oil and the candle nut oil with a ratio 1:1 could be used to provide high performance of climbing perch larvae.
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Judul: Growth and survival rate of climbing perch larvae Anabas testudineus Bloch. stocked at 10, 20, and 30 larvae/L that was conducted in 30 days.
Abstrak: Ikan betok Anabas testudineus merupakan salah satu jenis ikan air tawar yang memiliki nilai ekonomis yang cukup tinggi sehingga berpotensi untuk dibudidayakan secara intensif. Namun, budidaya ikan tersebut masih terkendala dalam produksi larva yaitu tingkat kelangsungan hidup (SR) yang masih rendah. Penelitian ini bertujuan untuk menentukan kepadatan optimal dalam pemeliharaan larva ikan betok. Penelitian dilakukan dengan padat penebaran 10, 20, dan 30 larva/L dan menggunakan 4 ulangan pada tiap perlakuan. Larva ikan betok berumur 10 hari dengan panjang rata-rata 0,49±0,06 cm ditebar sesuai dengan perlakuan. Larva tersebut dipelihara selama 30 hari di dalam akuarium berukuran 25x25x25 cm yang diisi air sebanyak 10 L. Pakan yang diberikan berupa artemia mulai awal sampai dengan 10 hari pemeliharaan kemudian diberikan cacing sutera sampai akhir pemeliharaan. Tingkat kelangsungan hidup tertinggi (51,5±5,57%) diperoleh pada perlakuan 10 larva/L sedangkan yang terendah (15,33±5,75% ) terdapat pada perlakuan 30 larva/L (p<0,05). Data pertumbuhan yang diperoleh menunjukkan bahwa pertumbuhan antar perlakuan tidak berbeda (p>0,05). Oleh karena itu berdasarkan hasil penelitian ini, pemeliharaan larva dapat dilakukan dengan padat penebaran 10 larva/L.
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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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