Effects of protein levels in commercial diets on growth performance and survival rate of rabbitfish (Siganus guttatus) at the nursing stage

Abstract

Abstract This study aims to determine how the levels of protein in commercial diets affect growth and survival rates of Siganus guttatus from the fry to fingerling stage. The experiment allocated 3 levels of protein in the diets: 35% (trial 1); 40% (trial 2) and 45% (trial 3) and each trial was repeated three times. The 30-day-old fry in this study had an initial length and weight of 18.25 ± 0.15 mm fish -1 and 0.036 ± 0.50 g fish -1 , respectively. In experimental setup, the stocking density was set to 1,000 fish m -3, and all the experimental fish were arranged in a composite tank with a volume of 1.0 m 3 . After 30 days of rearing, the weight of fingerlings in formula trial 1 reached 1.52 ± 0.01 g fish -1 , which was lower than that of trial 2, where fingerling weight was reported to be 1.69 ± 0.01 g fish -1 but was showed no difference from trial 3, which obtained a weight of 1.58 ± 0.08 g fish -1 . The length of fingerlings in trial 1 reached 36.92 ± 0.60 mm fish -1 , which was lower than that in trial 3 (45% CP) with lengths of 38.89 ± 0.43 mm fish -1, but not significantly different in trial 2 (40% CP) with a length of 37.97 ± 0.35 mm fish -1 . The survival rate of fingerlings ranged from 67.27 to 72.33%. Meanwhile, the herd distribution coefficient variation (CVw) in the treatment using 45% protein (trial 3) was the highest at 7.42% (p < 0.05).