PERKEMBANGAN GONAD DAN PERTUMBUHAN IKAN NILEM BETINA ALL FEMALE HASIL FERTILISASI JANTAN NEOMALE

Abstract

Dalam memenuhi kebutuhan produksi diperlukan ketersediaan induk betina yang unggul. Pembentukan all female berasal dari pemijahan jantan fungsional (aplikasi hormon metil testosteron) hasil secara pool gamet dengan betina normal. Penelitian ini bertujuan mengevaluasi perkembangan gonad dan pertumbuhan ikan nilem betina (all female) hasil fertilisasi jantan fungsional (neomale). Pemeliharaan ikan uji all female dilakukan dalam jaring polyetilene berukuran 2 m x 2 m x 2 m dengan kepadatan 60 ekor di Instalasi Penelitian Toksikologi dan Lingkungan Budidaya Cibalagung Bogor. Selama enam bulan pemeliharaan ikan diberi pakan komersil berupa pelet dengan kandungan protein 28% sebanyak 5% dari bobot total dengan frekuensi tiga kali sehari (pagi, siang, dan sore). Pengamatan pertumbuhan dan pengambilan sampel ikan untuk materi histologi dilakukan setiap bulan. Hasil penelitian menunjukkan ikan all female dapat tumbuh dan berkembang normal. Secara statistik pertumbuhan ikan all female berbeda nyata (P<0,05) dibandingkan dengan kontrol, dengan nilai panjang (14,2 ± 2,35 cm), bobot (28,9 ± 2,24 g), dan pertumbuhan bobot relatif (58,79%). Pada perkembangan kematangan gonad ikan all female masuk pada tingkat III dan IV dengan nilai IGS sebesar 20,2% serta tidak ditemukan gonad intersex.

In order to supply sufficient seed for grow out industry, the availability of female broodstock takes the priority in hatchery operations. In order to reach that objective, all female seed batch for potential future broodstock could be produced by breeding functional males (induced with methyl testosterone hormone application) with a pool gametes of normal females. This study was aimed to evaluate the gonadal development and growth of all female Bonylip barb produced from fertilization of neomale and normal females. All the females were reared in polyethylene net cages (2 m x 2 m x 2 m in size) with a stocking density of 60 individuals/cage. The trial was conducted at the Cibalagung Toxicology and Environmental Research Station, Bogor. The fish were reared for six months and fed three times daily with commercial pellets (crude protein of 28%) as much as 5% of the total weight. Observations on the growth and fish sample collections for histology analysis were conducted every month. The results showed that all female fish were able to grow and develop normally. Statistically, the growth of all female was significantly different (P<0.05) compared to the control, with the length size of 14.2 ± 2.35 cm and weight of 28.9 ± 2.24 g and relative weight gain of 58.79%. In terms of gonadal development, all female fish reached stage III and IV with IGS value of 20.2% and no inter-sex gonad observed.