Search

Aeration plays a pivotal role in an intensive shrimp pond regarding shrimp growth and energy costs. The purpose of this study was to find a way to reduce energy costs while maintaining shrimp performance. The study was carried out in about 0.3 hectares of outdoor ponds for 80 days with stocking density being set to 80 shrimp/m2 in two types of treatment an Automatic (AP) and a Manual paddlewheel (MP). Parameters observed were dissolved oxygen (DO) concentration, temperature of water and pH, energy cost, and shrimp biomass. Resulting study found that mean DO concentrations in both treatments were not significantly different, which were 4.99 ± 1.45 ppm and 4.94 ± 1.54 ppm for AP and MP respectively. Temperature and pH were also found to be in same range of 26.81-34.08 oC and 7.8-8.3. Differences in paddlewheels had no effect on final biomass; AP produced 2249.56 ± 300.67 kg, while MP resulted in 1547.43 ± 359.04 kg. However, the treatments reduced total energy costs significantly, from $657.84 ± 6.13 for MP to $409.76 ± 3.52 for AP. Using of an automated paddlewheel based on real-time DO concentration can contribute significantly to lowering production costs and energy consumption without interfering with shrimp performance.

The application of fermentation is one of methods to increase food quality biologically. Availability of Jatropha curcas residual from oil factory be focused as a soybean meal or fish meal replacement. On the other hand, J. curcas residuals possess a toxic compound as well. This study aimed to examine the effect of Aspergillus niger on the nutrition and harmful content of J. curcas as a potential ingredient of feed. In brief, J. curcas residual was fermented with a detoxification method at 3 d, 5 d, and 7 d. Crude protein, fat, and crude fiber content were assessed to discover the biological responses of J. curcas post–fermentation while phorbol ester was evaluated to toxic content post–detoxification. The results showed that crude protein and fat content were highest on 7 d post–fermentation but it was no significant difference (p > 0.05). While crude fiber content showed significant difference which the 3 d fermentation had the highest content of fiber. For phorbol ester content, 3 d fermentation showed a better result than the control group (p < 0.05). The present findings suggest that A. niger is recommendable as starter to reduce fiber and toxic content of J. curcas residual at 3 d fermentation.

The performance test of solar powered ice maker is being held at the fish auction spot of Kramat, South Lampung for 6 hours. The spesification of ice maker are: having the production capacity of 105 – 120 kg/ day, producing flakes ice with 2 x 3 x 3 mm dimension. The spesification of solar panel are: having maximum power of 200 W, 1,32 m length, 0,992 m width, and 1,3094 m2 area. In this test, we used 9 solar panel with the total area of 11,7846 m2. During the performance test, the intensity of sunlight, battery voltage, battery capacity, power input from solar panel, battery discharge current, maximum power consumption of ice maker, and total ice production are being measured. The sunlight-intensity value (lumen / m2) and the power input of the solar panel (watts) was plotted into a graph. Once the graph is created then add the trendline and create the equation. In a sunny-yet-cloudy weather conditions (at 24-33°C temperature and 65-95% humidity) in South Lampung, the relationship between the sunlight intensity with the power input of the solar panel is linear with the equation y = 0,008x + 143.6. Where the maximum intensity of sunlight is 121600 lm / m2 with the maximum power input of the solar panel (9 x 200Wp) is 1253 W. Total ice production for 6 hours is 28.42 kg or 4.74 kg per hour. This production resulted from a 760 W ice maker with a starting current of 4.6 A with a total power of 3.94 kWh.