Ekspresi gen aromatase pada pengarahan diferensiasi kelamin ikan nila (Oreochromis niloticus Linnaeus 1758) menggunakan madu

Abstract

In tilapia aquaculture, all male populations are preferred because they achieve higher growth rates and prevent uncontrolled reproduction. Sex reversal techniques are largely used for the control of sex in fish farming and in fundamental studies on sex determinism mechanisms. The study was conducted to determine the effect of immersion Nile tilapia larvae in water containing different honey source on male percentage and aromatase gene expression. In experiment I, a total of 30 tilapia larvae at 12 days post hatch were immersed in water containing honey derived from the forest, cultured and mangrove bees, at a dose of 10 ml L-1 for 10 hours. Fish were maintained in the same condition for two months. The results showed that percentage of male fish was similar among honey treatments (p>0.05), and they were significantly different with the control (p<0.05). In experiment II, fish were immersed in two bioactive compounds of honey, namely chrysin and potassium solution in a dose of 20 mg L-1 and 0.026 g L-1, respectively, to verify the bioactive affects sex differentiation. Aroma-g expression was analyzed by RT-PCR method. Tissue was collected at 1, 6, 12, 24 and 48 hours after immersion, and 2-month-old fish. Size fragment DNA aroma-g of female 200 bp. Chrysin and potassium immersion increased male percentage (p<0.1), this indicated that both materials were involved in Nile tilapia sex differentiation. RT-PCR analysis showed that honey, chrysin and potassium down-regulated aroma-g expression at 12 hours post immersion. Thus, honey can be used for sex reverse of Nile tilapia, and the mechanism is most likely as aromatase inhibitors.

Abstrak

Budi daya ikan nila dengan populasi jantan semua (monoseks) lebih memberikan keuntungan karena laju pertumbuhan-nya lebih cepat dan dapat mencegah pemijahan liar.Teknik pengarahan diferensiasi kelamin(sex reversal) digunakan untuk mengarahkan pembentukan jenis kelamin pada budi daya ikan.Penelitian ini dilakukan untuk mengevaluasi pe-ngaruh perendaman larva ikan nila menggunakan tiga sumber madu berbeda terhadap persentase ikan jantan dan ekspresi gen aromatase. Pada percobaan satu, 30 larva ikan nila berumur 12 hari setelah menetas direndam menggunakan madu hutan, madu ternak dan madu bakau, dengan dosis 10 ml L-1 air selama 10 jam. Ikan dipelihara dalam kondisi yang sama selama dua bulan. Hasil penelitian menunjukkan bahwa persentase ikan jantan tidak berbeda nyata antar perlakuan madu (p>0,05), tetapi semuanya berbeda nyata dengan kontrol (p<0,05). Pada percobaan kedua, larva ikan nila direndam dalam air mengandung dua bahan bioaktif madu, yakni chrysin dan kalium dengan dosis masing-masing 20 mg L-1 dan 0,026 g L-1. Ekspresi gen aromatase tipe gonad (aroma-g) dan tipe otak (aroma-o) dianalisis menggunakan metode RT-PCR. Sampel jaringan diambil pada waktu 1, 6, 12, 24, dan 48 jam pascaperlakuan madu, chrysin, dan kalium, serta setelah ikan berumur dua bulan.Ukuran fragmen DNA aromatase pada gonad betina sekitar 200 bp. Perendaman chrysin dan kalium meningkatkan persentase ikan jantan (p<0,1). Analisis RT-PCR menunjukkan bahwa madu, chrysin, dan kalium dapat menekan ekspresi gen aroma-g pada jam ke-12 pascaperendaman. Dengan demikian dapat disimpulkan bahwa madu, chrysin dan kalium dapat digunakan untuk pengarahan diferensiasi ikan nila, dan mekanis-menya seperti penghambat aromatase.