Amino Acid Absorption by Tiger Grouper Fish(Epinephelus fuscoguttatus) Larvae

Kerapu (grouper fish) is known as an important and highly economic value fish and a good candidate for major export commodity for Indonesia. However, there is an important problem faced by its cultivation i.e. high mortality rate at larva stage. Many different efforts have been done to overcome this problem mainly by using drugs and antibiotics, which have caused another problem i.e. bacteria resitance. One aspect that has not been widely investigated is by increasing its growth rate so that the larvae will have the ability to avoid mortality, such as by utilising dissolved organic matter (DOM) which naturally occur in the environment. This research investigates the question whether Kerapu fish larvae have the ability to absorb DOM (in this case disolved free amino acids; DAA) as well as the preference and the rate of absorbsion. There were 16 species of DAA used in this experiment which consist of three classes i.e. neutral, basic, and acidic. Two days old larvae were used in the experimant. The results showed that Kerapu larvae absorbed all classes of amino acids, although not all amino acids given being absorbed but only glutamine, histidine, lysin, serine, triptophan, metionine and iso leusine. While the most absorbed amino acids was lysine. One interesting results showed that the larvae secrete several amino acids i.e. glysine, alanine, tyrosine, valine, phenil alanine and leusine. The absorbsion and secretion of amino acids were possibly related to its metabolic processes within the larvae in relation to growth processes.