Pertumbuhan, Ekspresi Gen GH, dan Ghrelin Ikan Nila Nirwana (Oreochromis niloticus) Pascacekam Salinitas

Abstract

ELVARETTA CAHYA CAMILLA ANSORI. Pertumbuhan, Ekspresi Gen GH dan Ghrelin Ikan Nila Nirwana (Oreochromis niloticus) Pascacekam Salinitas. Dibimbing oleh ALIMUDDIN dan DINAR TRI SOELISTYOWATI. Cekaman salinitas merupakan faktor lingkungan yang dapat memengaruhi respons fisiologis ikan melalui tekanan osmotik. Ikan nila (Oreochromis niloticus) bersifat euryhaline sehingga memiliki kemampuan adaptasi terhadap perubahan salinitas. Penelitian ini menganalisis ekspresi gen growth hormone (GH) dan ghrelin serta hubungannya dengan performa pertumbuhan ikan nila nirwana yang diberi cekaman salinitas sejak usia benih. Penelitian menggunakan rancangan acak lengkap dengan dua perlakuan, yaitu kontrol dan cekaman salinitas 20 ppt selama 8 jam, masing-masing tiga ulangan. Benih pascacekaman dipelihara di media air tawar selama 75 hari. Parameter yang diamati meliputi kualitas air, tingkat kelangsungan hidup, laju pertumbuhan spesifik, bobot dan panjang akhir, biomassa, serta ekspresi gen GH dan ghrelin yang dianalisis menggunakan qPCR dengan ß actin sebagai gen referensi. Hasil menunjukkan bahwa cekaman salinitas meningkatkan ekspresi gen GH dan ghrelin pada ikan yang mampu bertahan hidup hingga akhir pemeliharaan, dan biomassa akhir lebih tinggi pada kelompok ikan jantan perlakuan. Kata kunci: Cekaman salinitas, ekspresi gen, ghrelin, growth hormone, ikan nila nirwana.

ELVARETTA CAHYA CAMILLA ANSORI. Growth, GH and Ghrelin Gene Expression of Nirwana Tilapia (Oreochromis niloticus) After Salinity Stress. Supervised by ALIMUDDIN and DINAR TRI SOELISTYOWATI. Salinity stress is an environmental factor that can influence the physiological responses of fish through osmotic pressure. Nile tilapia (Oreochromis niloticus) is a euryhaline species with the ability to adapt to changes in salinity. This study analyzed the expression of growth hormone (GH) and ghrelin genes and their relationship with the growth performance of Nirwana tilapia strain subjected to salinity stress since the juvenile stage. The experiment used a completely randomized design with two treatments, namely a control and salinity stress of 20 ppt for 8 hours, each with three replicates. The juveniles were reared in freshwater for 75 days after the stress treatment. The observed parameters included water quality, survival rate, specific growth rate, final weight and length, biomass, and the expression of GH and ghrelin genes analyzed using qPCR with ß-actin as the reference gene. The results showed that salinity stress increased the expression of GH and ghrelin genes in fish that survived until the end of the rearing period, and higher final biomass in the male fish treatment group. Keywords: Gene expression, ghrelin, growth hormone, nirwana tilapia, salinity stress.