Judul: Effect of Turmeric Powder (Curcuma longa) Supplemented feed on Indonesian shortfin eel (Anguilla bicolor bicolor) gonadal development
Abstrak: Anguilla bicolor bicolor merupakan komoditas dengan nilai ekonomis tinggi. Namun, budidaya sidat masih bergantung pada benih hasil tangkapan alam, serta menggunakan pakan yang tidak sesuai dengan kebutuhan sidat. Tujuan penelitian ini adalah menganalisa pengaruh suplementasi serbuk kunyit pada pakan formulasi terhadap kematangan gonad ikan sidat. Sidat dipelihara dalam bak beton berukuran 3 x 1,5 x 1,3 m. Padat tebar dari tiap kolam uji yang digunakan adalah 12 ekor per kolam. Sidat dipelihara selama 56 hari dengan diberikan perlakuan K, NS, dan S. Parameter yang diamati adalah pertumbuhan biomassa mutlak, rasio konversi pakan, indeks pencernaan, indeks hepatosomatik, indeks gonadosomatik, dan gambaran mikroskopis gonad. Hasil menunjukkan perlakuan pakan suplementasi memberikan hasil yang terbaik dalam meningkatkan perkembangan gonad sidat. Pakan formulasi yang disuplementasi kunyit mampu meningkatkan perkembangan gonad sidat ditunjukkan dengan adanya peningkatan pada indeks pencernaan yang lebih baik jika dibandingkan dengan perlakuan pakan komersial, yakni meningkat hingga 31%. Dalam penelitian ini, perlakuan pakan suplementasi merupakan perlakuan terbaik., Indonesian shortfin eel (Anguilla bicolor bicolor) is a commodity with high economical value. Unfortunately, its culture still depends on wild catch seeds, and using improper feeds with its requirement. The objective of this research is to analyze the effect of turmeric powder supplementation on European eel’s gonadal development. The aim of this research was to analyze the effect of turmeric powder supplementation on feed to improve Eruopean eel gonadal development. Eels was reared on 3 x 1.5 x 1.3 pond. Each pond was filled with 12 eels. Eels was reared for 56 days with K, NS, and S treatments. Parameters observed were absolute biomass growth, feed convertion ratio, digestive tract somatic index, hepatosomatic index, gonadosomatic index, and gonad microscopical image. Results showed that supplemented feed treatment gave the best result on increasing eels gonadal development. Supplemented feed was able to increase DTSI better than commercial feed, up to 31%. On this research, supplemented feed treatment was the best treatment.
Keyword: Indonesian Shortfin Eel, Feed, Gonad, Growth, Trumeric

Judul: Pemberian Pakan Pelet dengan Sumber Protein Berbeda terhadap Kinerja Pertumbuhan Ikan Sidat Anguilla bicolor bicolor Stadia Yellow eel
Abstrak: The main problems found in Indonesian shortfin eel production were slow growth rate and relatively high feed conversion ratio. Feed is one of main aspects which directly affects growth rate. The purpose of the recent study was to find out the best main protein source for Indonesian shortfin eel feed in form of pellets between shrimp meal, imported fish meal, or combination between shrimp meal, imported fish meal and local fish meal to improve the growth rate of Indonesian shortfin eel at yellow eel stage. Main protein sources used for feed production in the recent study were shrimp meal, imported fish meal, and combination of shrimp meal, imported fish meal and local fish meal. Commercial feed were also used as control. Research was performed using 8 units of aquarium with dimension of 90x50x40 cm3 with total water volume of 120 liters. The average weight of eels used in the recent study was 100,99 ± 0,88 gram/eel. Observed parameters in the recent study consisted of survival rate, daily growth rate, feed conversion ratio, and water quality parameters (water physics and chemistry). Based on overall observed parameters scoring, feed with main protein source of imported fish meal were the best treatment in the recent study to improve growth rate of Indonesian shortfin eel at yellow eel stage using feed in form of pellets. Therefore, imported fish meal could be utilized as main protein source in Indonesian shortfin eel feed production because it was estimated to contain the most compatible nutrient composition with the growth requirements of Indonesian shortfin eel
Keyword: growth performance, pellet, protein source, eel

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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