Judul: Seleksi bakteri proteolitik dan aplikasi enzim protease untuk meningkatkan kualitas pakan dan kinerja pertumbuhan ikan nila
Abstrak: Growth performance of fish is highly influenced by the quality of feed, which is determined dominantly by the quality of feedstuff used and also by supplementation of exogenous enzymes. This study aimed to select protease producing bacteria, to optimize their existing potential in producing protease and to evaluate the effect of dietary supplementation of bacterial protease on feed quality and growth performance of nile tilapia. Ten strains were isolated from gastrointestinal tract of Clarias gariepinus and two of them were selected based on their maximum clear zone diameter on casein agar medium and the absence of pathogenic activity against the test fish. The incubation time for maximum protease production of two strains was 72 hours, and the optimum dosage of bacterial protease was 1000 ml /kg feed, which was determined based on the level of hydrolyzed protein. A feeding study was conducted using 7 treatments with 3 replicate groups of nile tilapia (average weight of 4,07 ± 0.25 g), reared under laboratory condition. Result showed that the addition of A1 and L1 bacterial protease gave a significant increase on feed comsumption, growth rate of nile tilapia, apparent digestibility of dry matter and crude protein, protein retention and efficiency in formulated feed. Fish survival was not different among the seven treatments. This result suggested that bacterial protease was effective in improving feed quality and growth performance of nile tilapia when it was added to formulated feed containing poorly digestible feedstuffs.
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Judul: Aplikasi Berbagai Dosis Bakteri Proteolitik L1k dalam Pakan untuk Pengendalian Streptococcosis pada Ikan Nila Oreochromis niloticus dengan Metode Kohabitasi
Abstrak: Tilapia is a popular freshwater commodity were attacked bacterial disease such as streptococcosis caused by Streptococcus agalactiae. The objective of this research are to assay added treatment of bacterial proteolytic L1k toward increase immune response immune of tilapia (Oreochromis niloticus) infected by Streptococcus agalactiae N14G with cohabitation method. In this study, fish were fed diets containing different doses of proteolytic bacteria of L1k with the doses of 1%, 2% and 3%. Control fish (positive control and a negative control) were not given feed containing probiotic. After that, the fish tested challenged by cohabitation method. Treatment of bacteria proteolytic L1k in different doses of 1%, 2% and 3% can increase the survival rate of tilapia (respectively for 93.33%, 95.56%, and 97.78%) compared with the positive control fish by 68.89%. The addition of bacteria proteolytic L1k as probiotics to the diet may increase the immune response
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Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite