Judul: Birth Time Synchronization of Guppy Poecilia reticulata Using  Different Combinations of Temperature and Oxytocin Hormone Dose
Abstrak: Ikan gapi termasuk ke dalam jenis livebearer, yaitu telur berkembang dan menetas dalam tubuh induk yang selanjutnya dilahirkan dalam bentuk anak. Pemijahan massal ikan gapi terdapat kendala, yaitu waktu melahirkan induk yang tidak sinkron, sehingga sulitnya manajemen pemeliharaan yang mengakibatkan produksi menjadi tidak efisien. Penelitian ini bertujuan menentukan dosis hormon oksitosin dan suhu yang digunakan untuk meningkatkan sinkronisasi waktu melahirkan ikan gapi. Metode yang digunakan adalah perendaman induk gapi bunting selama 12 jam. Penelitian ini menggunakan rancangan acak lengkap faktorial dengan delapan perlakuan dan tiga kali ulangan. Dosis oksitosin yang digunakan adalah 0; 0,1; 0,2; 0,4 mL.L-1 pada suhu 28 °C dan 31 °C. Perlakuan hormon oksitosin dosis 0,4 mL.L-1 melalui perendaman induk gapi bunting selama 12 jam, dapat meningkatkan sinkronisasi waktu kelahiran 53,33–56,67% pada suhu 28 °C dan 31 °C. Tidak ditemukan adanya interaksi antara suhu dan dosis hormon oksitosin terhadap persentase induk melahirkan., Guppy is included in the type of livebearer, where the eggs develop and hatch in the broodstock's body which are then born in the form of larvae. The mass spawning of guppy has several problems due to its out of sync birth time, which makes it difficult for the maintenance management and resulting in inefficient production. This study aims to determine the dose of oxytocin hormone and temperature used to increase the birth time synchronization of guppy. The method used was through immersion of the broodstock of guppy for 12 hours. This study used a factorial completely randomized design with eight treatments and three replications. The dose of oxytocin used was 0; 0,1; 0,2; 0,4 mL L-1 at 28 °C and 31 °C. The oxytocin dose of 0.4 mL.L-1 by immersing the broodstock of guppy for 12 hours, can increase the birth of synchronization from 53.33 to 56.67% at 28 °C and 31 °C. There was no interaction between temperature and oxytocin dose treatment on the percentage of broodstock giving birth.
Keyword: :guppy, immersion, oxytocin, synchronization, temperature

Judul: Effect of Adding Oodev and Melatonin Through  Feed on The Production and Performance of Fish Seed Guppy (Poecilia reticulata,  Peters 1859)
Abstrak: Ikan gapi (Poecilia reticulata) merupakan salah satu jenis ikan hias air tawar yang banyak dibudidayakan karena mudah dalam proses budidayanya. Permintaan ikan gapi pada tahun 2019 adalah sebanyak 224.000 ekor namun hanya terpenuhi sebanyak 72.099 ekor atau 32,19% dari total permintaan. Selanjutnya permintaan ikan gapi pada tahun 2020 ditargetkan hanya sebanyak 70.311,70 ekor dan hanya terpenuhi sebanyak 61.097,89 ekor atau 86,9% dari total permintaan. Berdasarkan laporan tersebut terlihat bahwa produksi ikan gapi masih sangan rendah sehingga permintaan pasar jadi tidak terpenuhi, oleh karena itu dibutuhkan upaya untuk meningkatkan produksi ikan gapi. Salah satu upaya yang dapat dilakukan untuk meningkatkan jumlah produksi ikan gapi adalah manipulasi hormonal yang bertujuan meningkatkan produksi benih (larva) ikan. Penelitian ini menggunakankombinasi hormon Oodev dan Melatonin yang diduga mampu meningkatkan kinerja reproduksi ikan. Penelitian ini bertujuan mengetahui pengaruh Oodev dan Melatonin dengan dosis berbeda yang dicampur pada pakan terhadap produksi benih ikan gapi dan performa benih yang dihasilkan. Terdapat empat perlakuan berbeda, yaitu kontrol (tanpa penambahan hormon), Oodev 0,5 ml kg-1 + Melatonin 0,25 mg kg-1, Oodev 0,5 ml kg-1 + Melatonin 0,5 mg kg-1, serta Oodev 0,5 ml kg-1+ Melatonin 1 mg kg-1. Hasil penelitian menunjukkan penambahan Oodev dan Melatonin mampu mempersingkat periode waktu kelahiran pertama, meningkatkan produksi benih ikan gapi (15 kali lipat) dari kontrol, meningkatkan produksi anak gapi berjenis kelamin jantan, dan meningkatkan efisiensi biaya produksi ikan gapi dibandingkan kontrol. Dosis Oodev 0,5 ml kg-1 + melatonin 1 mg kg-1 menjadikombinasi terbaik yang menghasilkan jumlah anak tertinggi dan jumlah pendapatan tertinggi dari perlakuan lainnya., Guppy fish (Poecilia reticulata) is one type of freshwater ornamental fish that is widely cultivated because it is easy in the process of cultivation. The demand for guppy fish in 2019 was 224,000 head but only 72,099 head were fulfilled or 32.19% of the total demand. Furthermore, the demand for guppy fish in 2020 is targeted at only 70,311.70 head and only 61,097.89 head or 86.9% of the total demand are fulfilled. Based on these data, it can be seen that guppy fish production is still very low, so that market demand is not being met, therefore efforts are needed to increase guppy fish production. One of efforts to increase the amount of guppy fish production is hormonal manipulation aimed to improving the reproductive ability of fish. This study used a combination of the hormones Oodev and Melatonin which is thought to be able to improve the reproductive performance of fish. This study aims to determine the influence of Oodev and Melatonin with different doses mixed in feed on the production of fish seed guppy and the performance of the resulting seed. There are four different treatments i.e control (without the addition of hormones), the addition of Oodev 0.5 ml kg-1 + Melatonin 0.25 mg kg-1, the addition of Oodev 0.5 ml kg-1 + Melatonin 0.5 mg kg-1, and the addition of Oodev 0.5 ml kg-1 + Melatonin 1 mg kg-1. The results showed the addition of Oodev and Melatonin was able to shorten the time period of first birth, increase the production of guppy fish seeds (15 times), increase the
Keyword: guppy fish, Melatonin, Oodev, reproduction

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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