ABSTRACT

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Purpose Improving the nutritional value of rice straw by microbial inoculants and some physical treatments for animal feeding during dry seasons. Methods Different microbial inoculants and some physical treatments were used to improve the nutritional value of rice straw. Rice straw was divided into moist straw, soaked straw for 24 h without pasteurization and soaked for 24 h and pasteurized at 100 °C/1 h, and all of them were inoculated with different microbial inoculants. Results Moistened rice straw inoculated with Azotobacter chroococcum and Saccharomyces cerevisiae recorded the highest significant reduction in organic matter percent, 74.21%. The highest significant reductions in crude fiber, neutral detergent fiber, and acid detergent fiber percent were recorded in moistened rice straw inoculated with Azospirillum brasilense and Saccharomyces cerevisiae which gave 27.54, 55.39 and 42.47%, respectively. The highest significant increase in crude protein percent, 13.71%, was recorded in rice straw soaked for 24 h and inoculated with Azospirillum brasilense and Bacillus megaterium. The combined interaction between microbial treatments and physical pretreatments of rice straw gave a significant decrease in organic matter, crude fiber, neutral detergent fiber and acid detergent fiber %, as well as a significant increase in crude protein % compared to control. Addition of nitrogen fixers to rice straw improved its nitrogen contents. Conclusions This study showed the possibility of improving the nutritional value of rice straw using microbial inoculants and some physical treatments to produce safe and cheap animal feeds.

Maninjau Lake is the territorial waters of which contribute greatly to fish production in Agam, West Sumatra. But a lot of waste of economic activities discharged into the lake. This study aims to analyze the characteristics of fishing, contamination status of fishing ground and fish caught, to analyze the contamination pattern of fishing ground and fish caught as effect of economic activity waste. The methods used are descriptive method, physic-chemical analysis, correlation method, and multiple regression method. The results showed the fishing in Lake Maninjau, generally using langli net, lift net, hook and lines, and cast net. While the main fish caught are nile tilapia, bada fish, rinuak fish, carp, and limbek fish. Fishing ground in Maninjau Lake contaminated by ammonia, garbage, Cd and Hg metals, while the fish caught, there was found to have gills dirty. Significantly, fishing ground disturbed by the waste of hydropower (X1), lake tourism (X2), settlements (X4), and KJA fisheries (X5). The contamination pattern of fishing ground formulated by Y1=0,220X1+0,085X2+0,227X4+0,204X5-4,540. Fish production disturbed significantly by the waste from hotel and restaurants (X3), seattlements (X4), and KJA fisheries (X5). The contamination pattern of fish caught, represented by a decrease in fish production (Y2) formulated by Y2 =1,195X3+2,152X4+5,140X5-41,664.

Transition metal oxide (TMO) continues to be studied and developed as an oxygen evolution reaction (OER) electrocatalyst due to its abundance and low price. The aim of this experiment was to evaluate Ni2+-doped BaFe12O19 (BHF) as an OER electrocatalyst in an alkaline medium. BHF and Ni-doped BHF was synthesized through a low temperature coprecipitation technique followed by a calcination process at 750oC for 4 h. Diffractograms of the BHF and the Ni-doped BHF indicated a single phase on the synthesized BHF and formed Fe2O3 impurities on the Ni-doped BHF. SEM images showed a homogenous plate-shaped particles in the BHF, while the Ni-doped BHF had larger inhomogeneous particles. Ni dopant increased OER electrocatalytic activity of BHF based on overpotential on specific current density. The Ni-doped BHF had comparable activity to some metallic oxides based on their overpotential values at specific current density value.