ANALISIS EKSPRESI GEN Cu-SOD DAN HSP70 PADA BENIH HASIL SILANG IKAN LELE THAILAND DAN SANGKURIANG AKIBAT STRES NITRIT

Abstract

Kadar nitrit yang tinggi dalam air budidaya dapat menyebabkan stres oksidatif pada ikan. Nitrit dapat masuk ke dalam sel darah merah dan mengoksidasi besi dalam hemoglobin, dan menghambat transportasi oksigen. Persilangan ikan lele strain Thailand dan sangkuriang diketahui memiliki tingkat kelangsungan hidup lebih tinggi dibandingkan persilangan sesama strain Thailand. Penelitian ini menganalisis ekspresi gen Cu-SOD dan HSP70 pada benih lele hasil persilangan Thailand dan sangkuriang yang hidup dan mati akibat stres nitrit. Uji dilakukan dengan konsentrasi nitrit 22,6 mg/L (LC70-H24) sebanyak tiga ulangan dan satu kontrol. Masing-masing berisi 50 ekor ikan. Sampel ikan mati diambil pada jam ke-12 dan ikan hidup pada jam ke-24. Parameter yang diamati meliputi kualitas air, kelangsungan hidup, sel darah merah, kadar glukosa, serta ekspresi gen Cu-SOD dan HSP70. RNA diisolasi menggunakan GENEzol dan dikonversi menjadi cDNA. Ekspresi gen dianalisis dengan qPCR. Hasil menunjukkan paparan nitrit menyebabkan stres oksidatif. Ikan hidup menunjukkan ekspresi HSP70 lebih tinggi, menandakan respons protektif, sementara ikan mati menunjukkan ekspresi Cu-SOD lebih tinggi yang menandakan respons antioksidan yang tidak efektif.

High nitrite levels in aquaculture water can cause oxidative stress in fish. Nitrite can enter red blood cells and oxidize iron in hemoglobin, inhibiting oxygen transport. Crossbreeding between Thai and Sangkuriang catfish strains is known to have a higher survival rate than crossbreeding between Thai strains. This study aims to analyze the expression of Cu-SOD and HSP70 genes in Thai and Sangkuriang catfish hybrids that survived and died due to nitrite stress. The test was conducted with a nitrite concentration of 22.6 mg/L (LC70-H24) in three replicates and one control. Each contained 50 fish. Dead fish samples were collected at 12 hours, and live fish at 24 hours. Parameters observed included water quality, survival rate, red blood cell count, glucose levels, and gene expression of Cu-SOD and HSP70. RNA was isolated using GENEzol and converted into cDNA. Gene expression was analyzed via qPCR. The results showed that nitrite exposure caused oxidative stress. Live fish exhibited higher HSP70 expression, indicating a protective response, while dead fish exhibited higher Cu-SOD expression, indicating an ineffective antioxidant response.