Peningkatan sintasan dan kinerja pertumbuhan udang vaname (Litopenaeus vannamei, Boone) di media bersalinitas rendah

Abstract

The research was carried out in three phases. The first phase was to study the effect of adding calcium on the short-term survival of Pacific white shrimp postlarvae (Litopenaeus vannamei, Boone). Preliminary experiment consisted of 16 treatments in combination between the level of calcium (0 ppm, 50 ppm, 100 ppm, 150 ppm) and the medium salinity endpoint (0 ppt, 2 ppt, 4 ppt, 6 ppt). The second experiment consist of different Ca2+ level namely A (0 ppm Ca2+), B (50 ppm Ca2+), C (100 ppm Ca2+), D (150 ppm Ca2+), and D (25 ppt salinity /control). Several biological responses, including the survival rate in first trial, osmoregulatory capacity and oxygen consumption in the main trial, were discussed. Result of the first experiment showed that maximum percentage of mean survival rate was 92.2 % in B treatment (50 ppm Ca2+). No significant effect between calcium level observed on both osmoregulatory capacity and oxygen consumption, but it occurs lower in salinity 25 ppt and control. The second phase was conducted to determine the effect of potassium concentration medium on the metabolism, potassium whole body, survival rate, growth, and feed eficiency of L. vannamei postlarvae. Treatments consisted of different concentration of K+ added to distilled water. Four treatments were set, namely A, B, C, and D, where K2CO3 levels were 0, 30, 60, and 90 ppm, respectively. After the 42-days feeding trial, survival rate of the shrimp under the four treatments were not significantly affected by different K+ concentration in low salinity water. Solutions with K+ without or added K+ exhibited an average high survival rate above 83.33%. The final wet weight of the shrimp under treatment D (90 ppm K2CO3) were significantly higher, while the value of osmoregulatory capacity and oxygen consumption in treatment A (0 ppm K2CO3) significantly higher than those under the other four treatments.The aim of the third phase was to study the effect of protein and calcium level in the diet on the growth performance of postlarvae. Three level of dietary protein and three level of calcium was used in this experiment. Fifteen shrimp (PL25) were placed in triplicate 45-L glasses aquarium. The shrimp fed on the experimental diets four times daily, 8% of body weight. Feeding trial was conducted for 28 days. Growth performance was evaluated by RNA/DNA ratio, calcium and protein retention, frequency of moulting, daily growth rate, and feed efficiency. The last experiment showed that the survival rate was the same between treatments. Shrimp fed on diet 45% protein and 2% calcium produce higher RNA/DNA ratio, protein retention, daily growth rate, and feed efficiency compare to the other treatments. It was concluded that postlarvae L. vannamei require 45% protein and 2% calcium in low salinity condition.

Penelitian dilakukan dalam tiga tahap. Penelitian tahap pertama terdiri dari dua seri percobaan. Percobaan pertama bertujuan mengkaji pengaruh penambahan berbagai kadar kalsium pada berbagai salinitas media terhadap sintasan postlarva vaname (Litopenaeus vannamei, Boone). Rancangan yang digunakan adalah model faktorial terdiri enam belas perlakuan dengan 3 ulangan dibedakan berdasarkan penurunan salinitas (0 ppt, 2 ppt, 4 ppt, 6 ppt) dengan penambahan kalsium (0 ppm, 50 ppm, 100 ppm, 150 ppm) dalam media pengencer air tawar. Percobaan kedua merupakan pengulangan dari percobaan pertama pada salinitas akhir 2 ppt melalui evaluasi osmolaritas dan laju metabolisme. Rancangan percobaan menggunakan Rancangan Acak Lengkap terdiri 5 perlakuan berdasarkan penambahan kalsium dalam media yaitu: (A) 0 ppm, (B) 50 ppm, (C) 100 ppm, (D) 150 ppm, dan kontrol (salinitas 25 ppt) dengan 3 ulangan. Benih vaname (PL 20) yang digunakan diperoleh dari balai pembenihan (hatchery) komersial hasil pemijahan dari satu induk dalam upaya meminimalkan variasi unit percobaan. Setiap wadah diisi air bersalinitas 25 ppt yang kemudian diturunkan secara gradual selama 96 jam hingga salinitas perlakuan akhir 0 ppt, 2 ppt, 4 ppt, dan 6 ppt. Sedangkan pada percobaan kedua salinitas akhir yang dituju 2 ppt. Pemberian pakan Artemia dilakukan 4 kali perhari.