Free Amino Acid Enriched Rotifer for Larval Grouper Cromileptes altivelis

The hatchery production of grouper faced to the problem of low surival rate, especially during the first feeding period. During this period, the digestive organ of larvae was underdeveloped, and the nutrient in live food was not readily absorbed by larvae. Feeding on free amino acids, such as taurine or glutamine, enriched rotifer would be enhanced the nutrient readily absorbed thereby resulting to the improvement of growth and survival rate of larvae. A duplicate experiment was conducted to evaluate the effect of rotifer enriched with free amino acid of glutamine or taurine, on the growth and survival rate of larval grouper Cromileptes altivelis. One day old larvae were cultured in 500 l fiberglass containing 330 l of sea water with a density of 10 ind.L-1. Larvae were fed on rotifer enriched with either 0.5 g glutamine, 0.5 g taurine, or without glutamine nor taurine. Larvae were fed on rotifer twice a day at 08.00 and 14.00, and cultured for 16 days. One h after feeding, rotifer content in the gut of larvae were observed. Results showed that larvae fed on rotifer enriched with 0.5 g taurine or 0.5 g glutamie had higher rotifer content in the gut than that in the other group. Larvae fed on rotifer enriched with 0.5 g glutamine or 0.5 g taurine had the same survival rate (P 0.05), 19.2±2.25% and 24.5±1.20%, respectively; these values were significantly higher than that in the other group which was 13.0±1.70%. The total length of larvae fed on rotifer enriched with 0.5 g taurine (5.5±0.18 mm) significantly was the biggest compared than others; while those fed on rotifer enriched with 0.5 g glutamine (5.3±0.12 mm) was bigger than fish fed on rotifer without glutamine nor taurine (5.0±0.16 mm). Thus, it can be concluded that survival rate and growth of larvae were improved when feeding on rotifer enriched with taurine or glutamine. Nevertheless, taurine was more efective than glutamine due to its effect resulted the highest growth performance of larval grouper.