Judul: Growth performance and antioxidants of red tilapia (Oreochromis sp.) fed  with citral addition
Abstrak: Citral merupakan salah satu bahan aktif yang terkandung dalam berbagai bahan alami seperti serai dan kulit jeruk. Citral berpotensi untuk digunakan sebagai fitoadditive pada pakan untuk meningkatkan kinerja pertumbuhan melalui peningkatan pemanfaatan karbohidrat pakan dan antioksidan pada ikan nila merah. Penelitian ini bertujuan mengevaluasi pengaruh penambahan citral pada pakan terhadap kinerja pertumbuhan dan aktivitas antioksidasi pada juvenil ikan nila merah (Oreochromis sp.). Penelitian ini menggunakan lima perlakuan pakan dengan tingkat penambahan citral yang berbeda dengan empat ulangan. Dosis citral yang digunakan yaitu 0 mg/kg (kontrol), 25 mg/kg, 50 mg/kg, 75 mg/kg, dan 100 mg/kg pakan. Ikan nila yang digunakan berukuran 1,21 ± 0,02 g sebanyak 15 ekor yang dipelihara dalam akuarium 0,8 × 0,4 × 0,35 m3 selama 60 hari. Ikan diberi pakan secara at-satiation dengan frekuensi pemberian pakan tiga kali sehari. Hasil penelitian ini menunjukkan bahwa perlakuan penambahan fitoadditive citral pada pakan tidak berpengaruh pada biomassa akhir (252-286 g), bobot individu akhir (19,82-22,05 g), tingkat kelangsungan hidup (85- 93 %), rasio efisiensi protein (2,66-3,15), aktivitas antioksidasi (114-119 U/ g protein) dan rasio konversi pakan (1,20-1,15) pada ikan nila merah. Berdasarkan hasil tersebut maka dapat disimpulkan bahwa penambahan citral pada pakan sebanyak 25 - 100 mg/kg pakan tidak berpengaruh nyata terhadap kinerja pertumbuhan, pemanfaatan pakan dan aktivitas antioksidan pada juvenil ikan nila merah., Citral is one of the active ingredients contained in various natural ingredients such as lemongrass and orange peel. Citral has the potential to be used as a phytoadditive in feed to improve growth performance by increasing the utilization of feed carbohydrates and antioxidants in red tilapia. This study aims to evaluate the effect of adding citral to feed on the growth performance and anti-oxidation activity of red tilapia (Oreochromis sp.). This study used five dietary treatments with different levels of citral with four replicates. Citral doses used were 0 mg/kg (control), 25 mg/kg, 50 mg/kg, 75 mg/kg, and 100 mg/kg of feed. 15 tilapia fish measuring 1,21 ± 0,02 g were reared in an aquarium of 0,8 × 0,4 × 0,35 m3 for 60 days. Fish were fed at satiation with a frequency of three times a day. The results of this study indicated that the addition of phytoadditive citral had no effect on final biomass (252-286 g), final mean body weight (19,82-22,05 g), survival (85-93 %), protein efficiency ratio (2,66-3,15), antioxidant activity (114-119 U/g protein) and feed conversion ratio (1,20-1,15) in red tilapia. Based on these results, it can be concluded that the addition of citral to feed as much as 25-100 mg/kg of feed has no significant effect on growth performance, feed utilization and antioxidant activity in red tilapia.
Keyword: antioxidation, citral, growth, red tilapia

Judul: Growth Performance of Tilapia (Oreochromis niloticus) with the Addition of Antioxidant Astaxanthin to Feed
Abstrak: Astaxanthin sebagai antioksidan diketahui memiliki peran penting terhadap daya imunitas pada ikan, seperti daya tahan terhadap stres lingkungan dan penyakit yang dapat mendukung pertumbuhan ikan. Salah satu produk dengan bahan dasar astaxanthin yang biasa digunakan dalam kegiatan akuakultur ialah Lucantin. Penelitian ini bertujuan mengetahui pengaruh penambahan astaxanthin yang terkandung dalam Lucantin pada pakan terhadap pertumbuhan ikan nila. Penelitian menggunakan rancangan acak lengkap dengan 4 perlakuan, yaitu L0 (100% pakan komersial), L50 (100% pakan komersial + lucantin 50 mg/kg pakan), L100 (100% pakan komersial + lucantin 100 mg/kg pakan), dan L150 (100% pakan komersial + lucantin 150 mg/kg pakan) masing-masing 3 ulangan. Ikan nila merah dengan bobot awal 7,40±0,01 g/ekor dipelihara selama 50 hari dalam akuarium. Hasil penelitian menunjukkan kinerja pertumbuhan ikan nila yang diberi penambahan astaxanthin lebih tinggi dan menunjukkan hasil berbeda nyata (p<0,05) dibanding pakan kontrol atau tanpa penambahan astaxanthin. Parameter yang dapat menggambarkan pertumbuhan ikan seperti nilai biomassa akhir, bobot individu akhir, dan average daily growth menunjukkan pakan perlakuan L100 memiliki nilai yang tertinggi dan berbeda nyata (p<0,05) dari ketiga perlakuan lainnya. Pakan perlakuan L100 juga menunjukkan nilai rasio efisiensi protein dan retensi protein tertinggi yang menggambarkan tingkat efisiensi pemanfaatan pakan. Disamping itu, perlakuan pakan perlakuan L100 juga memiliki nilai rasio konversi pakan dan feed cost per gain terendah di antara perlakuan lainnya. Berdasarkan hasil penelitian ini disimpulkan penambahan Lucantin dosis 100mg/kg pakan dalam pemberian pakan ikan nila menunjukan kinerja pertumbuhan yang terbaik., Astaxanthin as an antioxidant is known to play an important role in the immune power of fish, such as resistance to environmental stress and diseases that can support fish growth. One of products with astaxanthin as the basic ingredient that is commonly used in aquaculture activities is Lucantin. This study aimed to determine the effect of adding astaxanthin contained in Lucantin to feed on the growth tilapia fish. The study used a complete random draft with 4 treatments, namely L0 (100% commercial feed), L50 (100% commercial feed + lucantin 50 mg/kg feed), L100 (100% commercial feed + lucantin 100 mg/kg feed), and L150 (100% commercial feed + lucantin 150 mg/kg feed) 3 replicates each. Red tilapia fish with a starting weight of 7.40±0.01 g/tail were kept for 50 days in an aquarium. The results showed that the growth performance of tilapia fish supplemented with astaxanthin was higher and showed significantly different results (p<0.05) compared to control feed or without the addition of astaxanthin. Parameters that can describe fish growth such as final biomass value, final individual weight and average daily growth show that treatment L100 feed has the highest value and is significantly different (p<0.05) from the other three treatments. Treatment L100 feed also showed the highest protein efficiency ratio and protein retention values which describe the level of feed utilization efficiency. Apart from that, feed treatment L100 also had the lowest feed conversion ratio and feed cost per gain values among the other treatments. Based on the results of this research, it was concluded that addition of Lucantin at a dose of 100 mg/kg to the feed when feeding tilapia showed the best growth performance
Keyword: antioxidant, feed, growth, lucantin, tilapia

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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