HERITABILITAS DAN RESPONS SELEKSI PERTUMBUHAN IKAN LELE AFRIKA (Clarias gariepinus) PADA PEMELIHARAAN MENGGUNAKAN PAKAN BERKADAR PROTEIN RENDAH

Abstract

Pembesaran ikan lele Afrika (Clarias gariepinus) di Indonesia menghasilkan keuntungan usaha yang rendah karena tingginya harga pakan komersial berkadar protein tinggi, sehingga perlu dibentuk strain baru yang pembesarannya dapat dilakukan menggunakan pakan berkadar protein rendah melalui program seleksi. Populasi dasar ikan lele Afrika yang pembesarannya menggunakan pakan buatan komersial berkadar protein rendah (12%) telah dilakukan melalui seleksi individu. Penelitian ini bertujuan untuk mengevaluasi heritabilitas dan respons seleksi pertumbuhan dari keturunan populasi dasar (populasi seleksi) tersebut. Masing-masing sebanyak enam pasang populasi dasar dan populasi kontrol dipijahkan. Larva dari setiap pasangan induk dipelihara selama tiga minggu tahap pemeliharaan larva dan satu bulan tahap pendederan. Selanjutnya, pada tahap pengujian sebanyak 150 ekor benih dari setiap pasangan induk dipelihara selama tiga bulan dengan menggunakan pakan buatan komersial berkadar protein 12%. Hasil pengujian ini menunjukkan bahwa populasi seleksi memiliki keragaan pertumbuhan (bobot akhir 35,35 ± 2,22 g dan laju pertumbuhan spesifik 1,83 ± 0,08%/hari) dan rasio konversi pakan (5,36 ± 0,94) yang relatif lebih baik daripada populasi kontrol (bobot akhir 30,37 ± 2,52 g; laju pertumbuhan spesifik 1,77 ± 0,14%/hari dan rasio konversi pakan 5,43 ± 1,05); dengan sintasan yang relatif sama (54,56 ± 2,21% pada populasi seleksi dan 54,78 ± 6,30% pada populasi kontrol). Respons seleksi (sebesar 6,00%) dan heritabilitas nyata (sebesar 0,11) karakter bobot akhir selama tahap pembesaran tersebut relatif rendah, sehingga perlu ditindaklanjuti dengan seleksi famili.

Grow-out farming of the African catfish (Clarias gariepinus) in Indonesia generally resulted in low economic return due to high cost of feeds containing high dietary protein levels. Thus, a new strain capable of using low dietary protein levels for optimal growth needs to be developed via selection programs. A base population of the African catfish fed with a low dietary protein level (12%) during the grow-out phase has been produced via individual selection. The present study was carried out to evaluate the heritability and response to selection for growth in the offspring of the base population (selected population). Six pairs of the base and control populations were selected and spawned. The produced larvae from each pair of both populations spent three weeks of larval rearing and four weeks of nursery phase. Post nursery phase, 150 juveniles from each pair were fed with a commercial feed containing 12% crude protein for three months of grow-out phase. During the grow-out phase, the selected population exhibited higher growth performances (final body weight of 35.35 ± 2.22 g and specific growth rate of 1.83 ± 0.08%/day) and relatively lower feed conversion ratio (5.36 ± 0.94) than the control population (final body weight of 0.37 ± 2.52 g, specific growth rate of 1.77 ± 0.14%/day and feed conversion ratio of 5.43 ± 1.05). The selected and control populations had a relatively similar survival rates of 54.56 ± 2.21% and 54.78 ± 6.30%, respectively. The response to selection (6.00%) and realized heritability (0.11) values for the final body weight during the grow-out phase were considered relatively low. Therefore, future research should continue to improve the findings of this research through family selection.