The growth, production, and content of chemical compounds in Chlorella sp. in various concentrations of liquid waste from palm oil were examined from June to November 2019, located in the Palm Oil Industry, SeiGaluh, Kampar, Indonesia. Five different concentrations of oil palm wastewater, i.e., 15 %, 20 %, 25 %, 30 % and 0.0 % (control) were studied. The results of this study indicated that oil palm wastewater was able to increase the growth, production, and chemical content of Chlorella sp. The best growth for Chlorella sp. was found at a concentration of 25 % oil palm wastewater, with cell density (8.5 × 106 cells/mL), biomass (0.77 g/L), after being cultured for 13 days (culture period). Chemical compounds in Chlorella sp. also increased at a concentration of 25 %, and it was found that protein content was 45.09 %, lipid was 10.85 %, and carbohydrate was 12.77 %. The concentration of nitrate and phosphate in culture media was known to have decreased, where the highest reduction in nitrate occurred at the concentration of oil palm liquid waste of 25 %, from the initial state of 14.34 to 3.17 mg/L at the end of culture. There was a decrease in phosphate, from the initial conditions, 1.82 mg/L to 0.34. mg/L at the end of the study. Chlorella biomass harvested in this study was used as a complementary food material (pellets) for livestock in the province of Riau.
The research was carried out through case studies at six locations of mangosteen production centers in West Sumatra during the 2018 harvest season. The results showed that mangosteen fruit damage by yellow sap was distinguished from yellow sap in exocarp and endocarp with varying percentages between research locations. There was no correlation between yellow sap in exocarp and endocarp (r=0.0656). Yellow sap in exocarp and endocarp correlate with rainy days. The intensity of rainfall during the fruit development period does not correlate with yellow latex in the endocarp but the fluctuation in rainfall is very influential. Yellow sap at the lowest endocarp (15%) was found at the location of Station-5 with the lowest rainy day (44 days) and low rainfall fluctuations (40-240 mm/month) and the highest (47%) at Station-3 (104 days rain and rainfall fluctuations 96-512 mm/month). The Station-4 area with lower rainy days (80 days) but has high rainfall fluctuations (73-954 mm/month) also shows yellow latex at a higher endocarp (35%) compared to other locations. Yellow gum at the lowest exocarp (32%) found in Station-2 (63 rainy days, 00 m asl) and highest (69%) in Station-6 (94 rainy days, 490 m asl). Effect of rainy days and altitude on the sap yellow on the skin of the fruit can be explained through its relationship with environmental conditions needed for the proliferation of insects that cause yellow sap on the mangosteen rind.
The coastal area of East Lingga Subdistrict, Lingga Regency has been designated by the Lingga Regency government as the center for the development of shrimp pond cultivation. This study aims to determine the level of toxicity of the surfactant alkyl sulfate (AS) detergent to post larvae (PL) of Vannamei shrimp (Litopenaeus vannamei). An acute test was performed on PL10 samples exposed to AS media for 96 hours. Then the Median Lethal Concentration (LC50) value was calculated for 4 times (24 hours, 48 hours, 72 hours, and 96 hours). Furthermore, the PL-15 sample was AS in the sub chronic test, then the sample was exposed to AS media for 24 hours, then the growth rate and changes in the gill organ structure of the PL samples were observed. From the test results, it is known that the LC50 values in the AS test for the 24th, 48th, 72th, and 96th times of the shrimp larvae samples obtained LS50 values were 33.6 mg/l, 29.4 mg/l, respectively. 24.3 mg/l, and 22.8 mg/l. Subsequently, an increase in AS concentration by 17.11 mg/l in the rearing medium resulted in a decrease in the growth rate of post larvae. The acute and sub chronic testing period showed changes in the behavior of post-larvae samples. The histopathological observations found damage to the structure of the sample gill organs and hepatopancreas. Symptoms of damage to the structure of the gills began to appear at AS concentrations of 25.58 mg/l at time 96 and 72 with an LC50 value of 34.99 mg/l. Furthermore, it was also seen at an AS concentration of 9.78 mg/l at time 24. The results of this study found that AS toxicity to Vannamei larvae increased with increasing concentration and exposure time.
The aim of this study to find out the optimal level of salinity for the growth and survival of the mud crab (Scylla serrata). The weight of crab seeds were about 47.65-51.32 grams and the carapace length ranged from 64.35-71.30 mm, then put into 12 tanks (1 m x 1 m x 0.4 m) with a density of 4 crab seed per tank. During the maintenance of this test, mangrove crab was fed with fresh chicken intestines as much as 10% of its body weight per day. Water changes are carried out more than 150% per week. At the beginning of the experiment, each tank was conditioned to the same water salinity in all experimental units, namely 33 ppt. To see the effect of differences in salinity levels on the growth and survival of mud crabs, 4 treatments were made consisting of (A) 33 ppt salt content, (B) 31 ppt salt content, (C). The salt content is 29 ppt, and (D) the salt content is 27 ppt. From the results of this experiment, it is known that a decrease in the salt content of 4 ppt is the best treatment for the growth of mud crabs, but has no effect on the survival value.
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