Judul: Evaluation of Natural Chitosan as a Silage Additive: A Metabolomic-Metagenomic Approach
Abstrak: Ruminant livestock methane emissions contribute significantly to agriculture's massive environmental burden. Current animal nutrition research has focused on its ability to modify rumen fermentation in order to reduce methane emissions. Chitosan is a linear polysaccharide made up of two repeating units, Dglucosamine and N-acetyl-D-glucosamine, joined together by β-(1→4)-linkages made up of N-acetylglucosamine (GlcNAc) units. On the other hands, silage is a type of fodder preservation technology. Non-optimal ensilage can lower DM content and cause mold to emerge on silage produced. Chitosan added to silage reduced methane generation, improved nutritional and fermentative quality, and reduced yeast and mold on silage product. Pre-research examined the influence of commercial chitosan and crab shells, a source of chitin, on in vitro rumen fermentation properties. RJ4 (treatment with 1% commercial chitosan) reduces gas production, while RJ2-RJ3 (20-30% swimming crabs shell of DM) also reduces gas production and in vitro organic matter digestibility. Despite the fact that crab shells can reduce gas production, they are less effective than commercial chitosan. This implies that the crab shells should be further processed into chitosan to increase their value and efficacy as rumen modifiers. The first stage focuses on how to obtain the best chitosan product from various methods and sources. Crab shells and wooden grasshoppers were used as chitosan source species, while conventional and green chemistry extraction methods were used as chitosan extraction variations. Green chemistry extraction using crab shells as a source of chitosan produces more chitosan with higher yield, DD, and solubility. The Gram-positive bacteria Clostridium acetobutylicum and the Gram-negative bacteria Escherichia coli were used to evaluate this. At a concentration of 2,000 ppm, the green chemistry extraction method (M2) using crab shell (P1) as the source considerably decreased the growth of Clostridium acetobutylicum (P<0.05). The second stage, chitosan which is gets from the first stage was applied on TMR silage and evaluated this physical, chemical and microbiological quality, in vitro rumen fermentation characteristics and in sacco degradability. The level of chitosan consists of SA (TMR silage with distilled water control, 0% chitosan), SB (TMR silage with 1% acetic acid control, 0% chitosan), SC (TMR silage with 0.5% chitosan in 1% acetic acid), SD (TMR silage with 1% chitosan in 1% acetic acid) and SE (TMR silage with 1.5% chitosan in 1% acetic acid). Chitosan at a dosage of 1–1.5% (SD and SE treatments) improves the nutritional (lowering ether extract, increasing protein content, tends reducing weight loss and maintain the optimal pH for ensilage) and microbiological properties (increase LAB count as well as tend to reduce Clostridium population) of TMR silage without impairing its physical state. The addition of 1-1.5% chitosan (SD and SE treatments) has been shown to decrease total gas production, total protozoa, average methane production, acetateproportion and the acetate/propionate ratio, increasing propionate proportion. The degradation of dry matter was reduced by the inclusion of chitosan (SE treatment) whereas the degradation of organic matter and crude protein was enhanced which is evaluated by in sacco analysis The third stage discusses the metabolome profile in silage and rumen fluid samples, as well as microbiome dynamics in rumen
Keyword: TMR silages, chitosan, rumen modifier, metabolome, metagenome

Judul: Karakteristik Fermentasi Silase Daun Singkong (Manihot esculenta Crantz) dengan Aditif Gliserol dan Ekstrak Tanin Chesnut
Abstrak: Cassava leaves (Manihot esculenta Crantz) productivity has a big potential to be valuable protein supplement for ruminant. However, due to the abundant availability when crop, cassava leaves requires a storage technology to maintain its nutritious composition. The one of better way is by ensilage. The ensiling process of cassava leaves required additives because its low content of WSC. Additives used in this present study were glycerol and chesnut tannin extract. Meta-analysis of glycerol supplementation in vitro did to support the hypothesis regarding of glycerol usage to substitute energy source as silage additives. This study aimed to evaluate the glycerol supplementation on rumen fermentation characteristics in vitro by quantitatively meta-analysis, to evaluate the fermentation characteristics of cassava leaves silage with glycerol and chestnut tannin extract additives during ensilage and in vitro gas production. Meta-analysis quantitatively was applied to 13 experiments and 42 treatments dealing with glycerol supplementation in ruminant. Data were estimated by linear regression of each parameter and analyzed by general linier model procedure with glycerol levels as fixed effect. Data for both fermentation characteristics of cassava leaves silage and its in vitro gas production were analyzed using analysis of variance then significant means were separated using Duncan multiple range F-test. Cassava leaves was ensiled using four different types of additive on the laboratory-scale silo. They were control (without additive, S0), glycerol 3% DM (SG), chesnut tannin 3% DM (ST), and mix of glycerol 3% DM and chesnut tannin 3% DM (SGT). Parameters on meta-analysis and in vitro gas production study were in vitro digestibility, rumen fermentation characteristics and total gas production. Parameters on silage study were nutrient composition, organic acids and N-NH3 concentration. Glycerol supplementation on meta-analysis quantitatively did not affect the in vitro digestibility and total VFA. Total VFA insignificantly showed propiogenic characteristics. It significantly decreased molar proportion of acetate and iso-valerate. In contrast, molar proportion of propionate, butyrate and valerate significantly increased, and thus the ratio of acetate to propionate became declined linearly. Methane production decreased linearly although the total gas production significantly increased as an increasing levels of glycerol supplementation but showed low enteric methane and no effect for microbial protein production. Every single cassava leaves silages in present study showed well-preserved quality depended on high concentration of lactic acid, not detected butyric acid, low concentration of N-NH3 although the pH value slightly higher. In addition, the well-preserved quality also supported by a low reduction of OM content (about 0.2%) and not changed CP content in silage between week 0 and 4. Rumen fermentation characteristics of cassava leaves silage by in vitro gas production showed an increasing IVOMD and total VFA production between week 0 and 4, but the silage treatment was not significant on each week. Glycerol as silage additive at week 0 showed propiogenic properties but not appeared on SG and SGT week 4. Contrary, the main properties of chesnut tannin was shown on in vitro gas production of ST and SGT week 4 that reduced proportion of N-NH3 and iso-acid production related to amino acid degradation. Based on results, it can be concluded that meta-analysis
Keyword: chesnut tannin, glycerol, in vitro, Manihot esculenta Crantz, silage

Judul: Teknik penentuan posisi bintang berdasarkan pelat foto overlapping
Abstrak: Bintang adalah salah satu objek langit yang menarik untuk diamati. Untuk itu, pengetahuan tentang posisi bintang sangat diperlukan. Posisi bintang di langit dapat dihitung melalui foto bintang. Fotografi astronomi atau astrometri merupakan ilmu yang mempelajari metode untuk menentukan posisi bendabenda langit seperti bintang berdasarkan pelat foto (Kamp, 1967). Sebuah pelat foto berisi citra bintang-bintang yang sudah diketahui posisinya berdasarkan katalog dan citra bintang-bintang yang belum diketahui posisinya. Posisi bintang yang ada di katalog dinyatakan dengan (a,3). Bintang yang belum diketahui posisinya lebih banyak jumlahnya daripada bintang yang sudah diketahui posisinya. Citra bintang pada pelat foto berupa sebuah titik dalam bentuk tetap. Posisinya pada pelat merupakan hasil pengukuran pada bidang kartesius dan dinyatakan dengan (1;,fl). Hasil pengukuran tersebut kemudian direduksi menjadi koordinat terukur (x,y). Hubungan antara (a,3) dan (x,y) didekati dengan sebuah deret dengan konstanta-konsranta deret merupakan konstanta pelat. Nilai konstanta pelat diperoleh dengan menggabungkan hasil pengukuran posisi bintang pada masing-masing pelat menjadi sebuah persamaan normal (Jefferys, 1963). Hasil akhir dari gugus persamaan normal tersebut dijabarkan dalam bentuk nOlasi matriks partisi dan berupa sebuah sistem persamaan linier Ax = b di mana A adalah matriks jarang, dan x merupakan konstanta pelar yang akan dicari nilainya. Untuk menyelesaikan sistem persamaan linier terse but digunakan metode transformasi given. Konstanta pelat yang sudah diperoleh dengan menyelesaikan sistem persamaan linier di atas, kemudian disubtitusi ke sebuah persamaan untuk memperoleh posisi bintang yang tidak tercantum dalam katalog. .
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