Fertilized eggs and developing larvae of hatchery reared Asian seabass,
Lates calcarifer (Bloch), were analyzed to determine the changes occurring in their proximate and amino acid (AA) composition. The fertilized
dry egg weighed 31 μg and contained 13.71 μg (44%) protein, 8.48 μg (27%) lipid and 0.657 J of gross energy. Dry weight decreased
by 39% during hatching. The protein, lipid and carbohydrate nutrients decreased by 4.86, 4.15 and 0.09 μg, respectively from
egg to 2-days post hatching (dph) larvae (pre-feeding). The protein content of the spawned eggs and larvae were hydrolysed
to AA in the laboratory. The fertilized eggs had a total AA content of 42% of their dry weight. The egg contained 1.287 μg,
1.132 μg, 0.964 μg, 0.942 μg, 0.787 μg and 0.713 μg of leucine, lysine, arginine, valine, threonine and phenylalanine, respectively
and these six indispensable amino acids (IAA) constituted approximately 78% of the total IAA. In the early feeding stages
of
L. calcarifer larvae, the ratio of IAA/DAA increased from 0.797 in the pre-feeding stage to 1.632 after 2 days of feeding. During larval
growth of
L. calcarifer, the percentage contribution of isoleucine and leucine to total IAA contents increased, while it decreased for lysine, phenyl
alanine and arginine.
L. calcarifer larvae were found to have proteins, which are rich in glutamic acid, leucine and lysine, and poor in threonine and histidine,
suggesting high dietary leucine and lysine IAA requirement.
amino acids - biochemical composition - fish egg and larvae - larval nutrition
This revised version was published online in July 2006 with corrections to the Cover Date.