KANDUNGAN ASAM AMINO LISIN OPTIMAL DALAM PAKAN UNTUK PERTUMBUHAN BENIH IKAN KERAPU SUNU, Plectropomus leopardus

Abstract

Kerapu sunu merupakan salah satu kerapu yang mempunyai nilai ekonomi tinggi. Ketersediaan pakan buatan merupakan salah satu kendala pada pengembangan budidaya kerapu di samping ketersediaan benih. Informasi kebutuhan protein dan lemak optimum, energi, asam lemak, dan vitamin telah dimanfaatkan sebagai dasar untuk pengembangan pakan buatan untuk kerapu. Namun demikian, informasi kebutuhan asam amino untuk kerapu masih terbatas sekali. Untuk itu, telah dilakukan riset untuk mengetahui kandungan asam amino lisin optimal dalam pakan untuk pertumbuhan kerapu sunu. Percobaan dilakukan dalam 18 buah bak polikarbonat volume 30 L yang dilengkapi dengan sistem air mengalir. Setiap bak diisi 12 ekor benih kerapu sunu yang berasal dari hatcheri dengan bobot awal 17,6 ± 3,1g. Ikan diberi pakan percobaan dua kali sehari pada level satiasi selama 84 hari. Enam pakan percobaan dibuat berupa pelet kering dengan kandungan protein 45% dan mempunyai kandungan lisin berbeda, yaitu 1,71%; 2,21%; 2,71%; 3,21%; 3,71% dan 4,21%. Pakan percobaan mempunyai komposisi asam amino yang sama kecuali kandungan lisinnya. Percobaan dirancang menggunakan rancangan acak lengkap dengan 6 perlakuan beda level lisin dan tiap perlakuan terdiri atas 3 ulangan. Hasil percobaan menunjukkan bahwa perbedaan level lisin dalam pakan berpengaruh nyata terhadap pertumbuhan dan sintasan kerapu sunu. Berdasarkan data pertambahan bobot ikan diperoleh bahwa kandungan lisin optimal dalam pakan untuk pertumbuhan kerapu sunu adalah 2,84%.

Coral trout grouper is one among the most expensive species of grouper. The availability of a practical diet for grouper is still a major constraint to grow-out production besides of good quality of seed. Information regarding the optimum dietary protein and lipid levels, energy, essential fatty acids and vitamin requirements has been used to develop diet for grouper. However, very limited information is available on amino acid requirement for grouper. The objective of the study was to find out optimum lysine content in diet for growth of juvenile of coral trout grouper. A 84-day feeding experiment was conducted in 18 polycarbonate tanks of 30 L volume. Each tank was equipped with flow-through water system. Twelve hatchery_produced juveniles of coral trout grouper (17.6 ± 3.1 g BW) were stocked in each tank. Fish fed experimental diets twice everyday at satiation level. Six experimental diets with different lysine level of 1.71%, 2.21%, 2.71%, 3.21%, 3.71%, and 4.21% were prepared in form of dry pellet. All diets have the same protein level of 45% and the same amino acid composition to the amino acid composition of whole body protein of coral trout grouper, except for its lysine content. The experiment was designed based on completely random design with 6 treatments and 3 replications for each treatment. Result of the experiment showed that dietary lysine levels had significant effect on growth and survival of juvenile of coral trout grouper. Optimum dietary lysine requirement was calculated using orthogonal polynomial regression analysis. Based on weight gain data of indicates that the optimum lysine level in diet for growth of juvenile of coral trout is 2.84%.