Judul: Evaluation of rubber seeds (Hevea brasilliensis) fermented meal using rumen liquour as a protein source in diet of nile tilapia (Oreochromis niloticus).
Abstrak: This research is aimed to investigate the effect of replacing soybean meal with rubber seed meal (RSM) as protein sources for feed of Nile tilapia (Orecochromis niloticus) strain Nirwana. The fish (8.14 ± 0.08 g) were cultured in rearing aquaria (100x50x50 cm3) connected to a recirculating aquaculture system, and fed three times daily with 5 different concentrations of RSM feeds: A (0% RSM), B (25% RSM), C (50% RSM), D (75% RSM) and E (100% RSM), with the same protein content and gross energy: 31% and 433.5 kcal GE g-1 respectively. The study consisted of two phase. Phase one aims to determine the digestibility of feed (14 days) and phase two study aimed to growth performance (50 days). During the feeding period, some parameters were measured including feeding rate, feed efficiency, protein retention, fat retention, daily growth rate, cholesterol, triglycerides, feed digestibility, LDL (low density lipoprotein), HDL (high density lipoprotein), hepatosomatic indeks (HSI), glycogen in heart and muscle, and lipid in hearth and muscle. Experimental design was set according to completely randomized design with 5 treatments and 4 repetitions of each. Data were statiscally analysed with one-way analysis of variance (ANOVA) using software Minitab version 16.0, with 95% (p<0.05) confidence interval. The results showed that the replacement of soybean meal with the rubber seed meal at 50% gave the highest protein digestibility (92.95%) and total feed digestibility (70.30%). On the contrary, increasing rate of the replacement up to 100% decreased both protein digestibility and total feed digestibility to 86.79% and 54.58%. Substitution up to 75% and 100% showed low blood protein to 3.57% and 2.58%. Other results revealed that the use of 75% and 100% lead to the increasing of cholesterol, triglyceride and LDL (low density lipoprotein), but decreased HDL (high density lipoprotein). Overall, the replacement of soybean meal with fermented rubber seed meal as protein sources showed no significant different in fish growth rate; 3.43% (25% RSM), 3.42% (50% RSM) and 3.41% (control). This research result may suggest that rubber seed meal which was previously fermented with rumen liquid can be used to replace soybean meal as protein sources and can be used up to 50% in diet of nile tilapia.
Keyword: Alternative protein source, Oreochromis niloticus, rubber seed meal HDL and LDL

Judul: Utilization of hydrolized duckweed (Lemna minor) meal as a soybean replacement in Nile tilapia (Oreochromis niloticus) diet,
Abstrak: Tilapia is a fast growing fish widely cultured in many tropical and sub tropical countries. The recent production figures reported our global production estimates for 2015 is 5,576.8 metric tons. In developing countries the major challenges facing aquaculture industry is high cost of production associated with fish feeds. Feed represents 40-70% of operating costs for aquaculture operations, increasing expenses and potential declining supplies soybean meal have led scientists to search for less expensive but compatible alternative protein sources for fish feed; most of which are based on animal or plant protein sources. The objectives of study was to determine the incubation period for hydrolysis of duckweed and to evaluate the use of hydrolized duckweed as aprotein source for the growth performance of Nile tilapia Three experiments were conducted to determine the composition and digestibility of hydrolyzed duckweed meal by sheep rumen liquor as the replacement of soybean meal in the diet of Nile tilapia. The first trial examined the effectivity of sheep rumen liquor enzyme to decrease crude fiber contents of (DWM), the added volume of sheep rumen liquor was 100 ml/kg DWM and then it was incubated for 0, 12, 24 hr . The second trial was to evaluate the apparent digestibility of hydrolyzed DWM for Nile Tilapia, apparent digestibility were determined using chromic oxide indicator added to both reference diet and test diets. The feed ingredients used in the trial were hydrolyzed DWM (HDWM) and unhydrolyzed DWM (DWM). Ten fish with an average weight of 18±0.36g were used in the trial and reared in the aquarium of size 30×40×50cm for 15 days; feces were collected from three replicates using a fecal collection column attached to the aquarium. Third trial was to evaluate the growth performance of Tilapia fed test diet with hydrolyzed Duckweed meal (HDWM). The experimental design was set according to completely randomized design with four treatments and three replicates of HDWM inclusion levels that is 0%, 15%, 30% and 45%. Nile tilapia fish with initial body weight of 18±0.36g was kept in 12 units aquarium size of 30×40×50cm at stocking density of 10fish/aquarium, the fish were fed two times a day at 08:00am and 16:00pm to apparent satiation for a period of 60 days. The results indicated that duckweed meal (DWM) hydrolyzed with 100 mL/kg and incubated for 24 hrs showed the lowest crude fiber contents of 13.68% compared to other treatments. Total digestibility of hydrolyzed duckweed (HDWM) meal was 87.3% compared with unhydrolyzed duckweed (DWM) which was 66.8%. Total final weight (TFW), survival rate (SR), specific growth rate (SGR), feed conversional rate (FCR) and protein retention (PR) shows growth performance at 15% inclusion. The results of this study showed that 100mL/kg sheep rumen liquor at incubation period of 24 hr can be suitable for hydrolysis of duckweed to reduce crude fiber also hydrolyzed duckweed can substitute soybean meal at an incubation rate of 15% in the diet of Nile tilapia and had the same growth and FCR with control diet
Keyword: Digestibility, Duckweed meal, Growth performance, Sheep rumen

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf