Judul: Kecernaan nutrien dan performa sapi potong lokal yang mendapat suplemen ekstrak lerak (Sapindus rarak) pada ransum berbasis hijauan
Abstrak: This study was aimed to evaluate the addition level of S. rarak extract on nutrient digestibility and performance of local beef cattle fed high forage based ration. Animals used were 12 local beef cattles with average initial body weight of 171 ± 12.51 kg. The experimental design was randomized block design. The treatments were: P1 as a control diet with ratio of forage : concentrate was 70:30 (% Dry Matter); P2 was P1 which supplemented with 100 mg/kg body weight (BW) of S. rarak extract; P3 was P1 which supplemented with 200 mg/kg BW of S.rarak extract. The parameters measured were feed intake, nutrient digestibility, daily weight gain and feed efficiency. Data were analyzed by analysis of variance and significant differences among treatments were tested by Duncan’s test. The results showed that the addition of S.rarak extract on high forage based rations had no significant effect (P> 0.05) on dry matter feed intake, nutrient digestibilities, daily weight gain and feed efficiency ratio.
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Judul: Model of beef cattle production system based on local resources in Sumedang West Java
Abstrak: The aim of this research was to investigate the utilization of whole lerak extract to improve the in vitro fermentation, microbe diversity and performance of beef cattle fed with high forage based ration. There were four experiments i.e. 2 in vitro and 2 in vivo experiment. The first in vitro experiment evaluated the effect of whole fruit lerak extract with different levels (0;0.001; 0.01; 0.1 and 1 mg/ml) on ruminal fermentation and microbial diversity using native grass and concentrate (50:50, w/w) as a substrate. The second in vitro was aimed to investigate the effect of different level of lerak extract (0, 0.6, 0.8 mg/ml) on fermentation, population of rumen microbes and enzyme activity in the in vitro fermentation of diets composed of different ratios of forage and concentrate (90:10, 80:20, 70:30, w/w). The first in vivo study was conducted using 12 local beef cattle which received 3 different treatments of 0, 500 and 1000 mg lerak meal/kg body weight (BW). Daily gain, nutrient digestibility and blood profile were measured. Thus, the second in vivo study was conducted using 12 local beef cattle with three diets containing lerak extract of 0, 100 and 200 mg/kg body weight. Parameters measured were nutrient digestibility, fermentation products, feed intake and daily gain of beef cattle during 90 days treatment. In vitro experiment showed that 1 mg/ml of lerak extract reduced (P<0.01) protozoa population. The gas production tended to increase while methane production/ml gas was reduced but total methane production was same among treatments. Although lerak extract did not affect concentration of total VFA, it decreased molar proportion of acetic and butyric acid but increased that of propionic acid significantly (P<0.01) and improved the ratio of acetate: propionate. The population of some bacteria spesies most closely related to Prevotella ruminicola increased. The second in vitro experiment showed that there was no interaction between ratio of forage and level of lerak extract for all parameters. The addition of lerak extract did not affect dry matter digestibility, but reduced organic matter digestibility. In contrast, total VFA and propionate production increased (P<0.05) with 0.8 mg/ml lerak extract addition. Total numbers of Ruminococcus albus and Prevotella ruminicola were enhanced by increasing level of lerak extract in all diets, but numbers of Fibrobacter succinogenes tended to decrease. In vivo experiment showed that the addition of lerak meal 500 mg/kg BW in the beef cattle ration did not affect nutrient intake and digestibility. In contrast, lerak meal at higher level (1000 mg/kg BW) increased fibre intake and decreased nutrient digestibility (P<0.05) and white blood cells (P<0.01). There was no difference on average daily gain among treatments. The addition of lerak extract up to 200 mg/kg BW did not affect on nutrients digestibility. Total VFA and propionate proportion increased (P<0.05) and ratio of acetate:propionate decreased (P<0.05) with lerak extract addition. The used of lerak extract decreased NH3 concentration while nitrogen balanced and microbial crude protein synthesis similar among treatments
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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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