Lipids, fatty acids and free amino acids as indicators of egg and larval viability in Atlantic cod (Gadus morhua)

Clarke, Marsha Judy Roxanne (2008) Lipids, fatty acids and free amino acids as indicators of egg and larval viability in Atlantic cod (Gadus morhua). Masters thesis, Memorial University of Newfoundland.

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Abstract

In aquaculture, the ability to predict future performance potential of eggs and larvae can help optimize hatchery production and lower overall production costs. In this study, egg batches spawned by Atlantic cod (Gadus morhua) broodstocks were collected, incubated to hatch, and the larvae reared to yolk-sac absorption. Objectives were to determine whether lipid classes, fatty acids, and amino acids could be used as indicators of egg and larval quality; to compare the utility of biochemistry and blastomere morphology as indicators of future performance potential; and to study changes in egg and larval biochemistry during ontogenetic development. Variability in several lipids and free amino acids was significantly correlated with fertilization and hatching success, particularly the phospholipids and the monosaturated fatty acid 24:1. Lipids showed conservation throughout embryo development, while free amino acids were catabolized as a primary energy source. Several blastomere morphological measures in newly fertilized eggs (eg. cell symmetry, uniformity, margins and adhesions) showed positive correlations with hatching success. These results show that both biochemistry and blastomere morphology can be useful tools for determining the performance potential of egg batches in culture, and that free amino acids serve as a primary energy source for endogenous-feeding eggs and larvae.

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