Abstract— Feed supplements of oil and selenium have been studied for their effect on absolute weight growth and a descriptive picture of the nutritional content of protein, fat, cholesterol in tilapia baby fish. Feed experiments using Complete Randomized Design (6x3), R1 (basal/protein ration 28%); R2 addition of a mixture of coconut oil and hazelnut oil without Se and R3 (oil mixture 4%+Se 0.15 mg/kg); R4 (4% coconut oil + Se) and R5 (4% hazelnut oil + Se) and Rs (standard ration of protein 32%). Coconut is dominated by saturated fatty acids (lauric acid 42.67%), while hazelnut is dominated by linoleic unsaturated fatty acids (34.4%) and oleic acid (48.99%). Basal ration with the addition of a mixture of vegetable oils + Se resulted in an absolute growth of 27.33 g and a daily growth rate (DGR) of 0.43 g/day, and matched the Ration with high protein (32%). The addition of vegetable fats and selenium provides fish meat protein content 54.62%-58.54% and meat protein conversion (protein productive value) 27.68-32.03%. The fat content of meat and cholesterol ranges from 7.15%-10.20% and 75.43-103.97 mg/dL, respectively, and Se in tilapia meat ranges from 0.502- 0.753 mg/kg). Keywords—coconut, hazelnut, nutritional content of fish meat, selenium, vegetable oils I. INTRODUCTION long with the increase in the world population and public awareness of nutrition that is expected to lead to a 70% increase in total food production and demand for animal protein. Fish is a healthy source of meat for human consumption and the current trend in Indonesian society, that fish can also be consumed in small sizes commonly known as baby fish, one of which is tilapia commodities. Baby fish in the juvenile stage measure in length ranging from 3-4.5 cm [1]. The size has a good nutritional content for consumption. The nutritional content in fish is influenced by several factors including species, size, habitat and feed used [2]. Feed is a combination of several ingredients that contain nutrients both quantitatively and qualitatively, and is indispensable to achieve optimum growth in accordance with genetic potential and metabolic rate supported by the energy content of the feed. The thing that needs to be observed in the feed formulation is the harmony of the composition of the nutrients contained in it in accordance with the needs of the fish. Unsaturated fatty acids play a role in the production of quality meat [3]. The hazelnut plant (Aleurites moluccana) on every 100 grams of its meat contains 636 calories, 19 grams of protein, 63 grams of fat, 8 grams of carbohydrates, 80 mg of calcium, 200 mg of phosphorus, 2 mg of iron, 0.06 mg of B vitamins, and 7 g of water [4]. The coconut and hazelnut can be extracted and used as a source of saturated and unsaturated fatty acids for fish feed which is expected to increase the efficiency of tilapia feed. Quantitatively effective use of protein (the right amount) needs to be supported by information on the characteristics of energy sources that are expected to provide benefits to improve the efficiency of Tilapia feed (Oreochromis niloticus). Fats and fatty acids as part of lipids can serve as sparring proteins that are invaluable for growth, as fuel to produce metabolic energy in fish muscles. Basically, the need for fish fatty acids increases with increasing lipid levels and decreasing water temperature [5]. It is further stated that in freshwater fish in hot areas the need for fatty acids of carp feed and eel is met from fatty acids of series ω-3 and ω-6, while in tilapia it can be met from PUFA series ω-6. The main location of fat storage in the body of fish is in the muscles and liver, some are stored as mesenteric fat [6]. According to [3], the fat content in fish muscles varies greatly depending on species, age, spawning, feed, and muscle type. As for the trace mineral selenium in nutrients is necessary. The mineral Selenium serves as an activator of the Tyrosine hormone (T4) into thyroid (T3), affects growth and development, regulates cell differentiation, stimulates oxidative reactions and the speed of metabolism of the body which means it directly leads to the accumulation of excess carbohydrates, fats, and proteins [7]. Effect of oil and selenium as feed supplement on nutritional content, fatty acid profile, cholesterol and protein productive value in nile tilapia meat Kiki Haetami 1, Junianto Junianto 1 , Dan Abun Abun 2 , 1 Departement of Fisheries, Padjadjaran University, Indonesia 2 Departement of Animal Nutrition and Feed Technology, Padjadjaran University Jl. Raya Bandung-Sumedang KM.21, West Java, 45363, Indonesia Received: September 18, 2022. Revised: January 8, 2023. Accepted: February 9, 2023. Published: March 3, 2023. A INTERNATIONAL JOURNAL OF BIOLOGY AND BIOMEDICAL ENGINEERING DOI: 10.46300/91011.2023.17.5 Volume 17, 2023 Ε-ISSN: 1998-4510 42