PENGARUH KADAR PROTEIN DAN LEMAK PAKAN TERHADAP PERTUMBUHAN DAN KOMPOSISI BADAN IKAN KERAPU MACAN, Epinephelus fuscoguttatus

Abstract

Penelitian ini dilakukan untuk mendapatkan informasi tentang kebutuhan optimum kadar protein dan lemak pakan terhadap pertumbuhan dan komposisi badan ikan kerapu macan ukuran konsumsi. Sembilan pakan uji dibuat dalam bentuk moist pelet dengan tiga dosis protein (46%, 49%, dan 52%) dan tiga dosis lemak (9%, 11%, dan 13%). Ikan uji dipelihara dalam 27 keramba jaring apung ukuran 1 m x 1 m x 2 m selama 140 hari, diberi pakan uji secara satiasi dua kali sehari dan diset dalam rancangan acak kelompok pola faktorial berdasarkan kelompok ukuran bobot awal ikan yaitu (i) 122,0±4,2 g; (ii) 144,0±7,1 g; dan (iii) 172,9±10,5 g. Hasil penelitian menunjukkan bahwa laju pertumbuhan spesifik dan sintasan ikan relatif sama (>0,05) di antara perlakuan. Efisiensi pakan cenderung meningkat dengan meningkatnya kadar protein dan lemak pakan. Tingkat efisiensi pemanfaatan protein cenderung menurun dengan meningkatnya kadar protein pakan, tetapi meningkat dengan meningkatnya kadar lemak pakan. Hasil analisis proksimat badan ikan menunjukkan bahwa kadar bahan kering dan lemak ikan relatif tidak dipengaruhi (P>0,05) oleh peningkatan kadar protein pakan, namun kadar bahan kering dan lemak ikan tersebut sedikit naik dengan meningkatnya kadar lemak pakan. Kadar protein dan abu ikan relatif tidak dipengaruhi oleh perubahan kadar protein dan lemak pakan. Berdasarkan hasil penelitian ini tampak bahwa pakan dengan kadar protein 49% dan lemak sekitar 11% mampu memberikan pertumbuhan dan komposisi badan ikan kerapu macan yang baik.

This experiment was conducted to investigate the optimum dietary protein and lipid level for growth and body composition of tiger grouper. Nine dietary experiments were formulated to moist pellet contain three levels of protein (46%, 49%, and 52%) and three levels of lipid (9%, 11%, and 13%). The fish were fed twice daily to satiation for 140 days in twenty seven net cages of 1 m x 1 m x 2 m, were set up factorial randomized block design based on fish size group i.e. (i) 122.0±4.2 g, (ii) 144.0±7.1 g, and (iii) 172.9±10.5 g. The results shown that specific growth rate and survival rate were not significant different (P>0.05) for all treatments. Feed efficiency increased when protein and lipid content increased. Protein efficiency decreased when protein diets increased and increased when lipid diets increased. No interaction occurred between protein and lipid content to all observable biological variables. Dry matter and lipid content of test fish were not affected by protein diets increase but by lipid diet content. Protein and ash of test fish were not affected by either protein or lipid contained in diet. To assure high growth rates and high quality of fish product, it is suggested to feed tiger grouper with diet containing 49% protein and 11% lipid.