Changes in amino acid content of an algal feed species (Navicula sp.) and their effect on growth and survival of juvenile abalone (Haliotis rubra)

Abstract

The growth and survival of juvenile Haliotis rubra, when fed with the diatom Navicula sp. cultured in f/2 medium containing combined nitrogen at 24.71 mg NO3-N L-1 (high), 12.35 mg NO3-N L-1 (standard) or 2.47 mg NO3-N L-1 (low), were compared in a 33-day trial. The alga in the low nitrogen medium contained 37% less total amino acid than that in the high and standard nitrogen media. There was a slightly greater reduction in essential amino acids (40%) compared to non-essential amino acids (35%). Juvenile abalone feeding on Navicula grown in medium with low nitrate and lower total amino acid content grew more slowly than when fed on the same species grown in standard or higher nitrogen medium..