Comparative utility of egg blastomere morphology and lipid biochemistry for prediction of hatching success in Atlantic cod, Gadus morhua L.

Abstract

Six blastomere morphology parameters indicative of cell development abnormalities, egg diameter, dry weight, total lipid, lipid classes and fatty acids were determined for egg batches collected daily from three Atlantic cod (Gadus morhua) broodstock groups over the course of one spawning season. Egg batches were incubated to hatch and each morphological and biochemical parameter was tested as a predictor of hatching success. Five of the six blastomere morphology parameters were significantly positively correlated with each other. Correlation coefficients among several fatty acid parameters were also significant but correlation coefficients among the various lipid classes were mostly not significant. No significant correlations were found between blastomere morphology and lipid class or fatty acid parameters. Egg dry weight was negatively correlated with cell clarity, %docosahexanoic acid (DHA), DHA:eicosapentaenoic acid, and Σ polyunsaturated fatty acids. Fertilization success was not significantly correlated with any of the morphology or biochemistry parameters. Within‐population variability in several morphological and fatty acid parameters was related to elapsed time since onset of first spawning. However, the occurrence of such relationships with elapsed time was highly variable and inconsistent among the three broodstocks, typically being significant for only one or two broodstocks but not all three. Mean hatching success rates were high (>75%) in all three broodstocks but hatching success was not significantly related to any of the morphological or biochemical parameters nor to elapsed time from onset of first spawning. The implications of these results are discussed in terms of the utility of the various morphology and biochemistry parameters as measures of egg quality in marine finfish hatcheries.

Evaluation of egg quality in broodstock cobia Rachycentron canadum L.

“…Factors a¡ecting ¢sh egg quality can be broodstock nutrition, maternal condition factor and age, spawning cycles, over-ripening processes, the intrinsic properties of the egg itself and the environmental conditions under which broodstock ¢sh are held (KjÖrsvik et al 1990;Brooks, Tyler & Sumpter 1997). These include egg size, morphology, buoyancy, fertilization success (KjÖrsvik et al 1990;Bromage 1995;Brooks et al 1997) and biochemical composition such as lipid biochemistry (Sargent 1995;Pickova, Dutta, Larsson & Kiessling 1997;Nocillado, Pena£orida & Borlongan 2000;Tveiten, Jobling & Andreassen 2004;Penney, Lush, Wade, Brown, Parrish & Burton 2006), protein and amino acids (Srivastava & Brown 1992;Nocillado et al 2000) or vitamins (Maeland, Ronnestad & Waagbo 2003;Palace & Werner 2006). These include egg size, morphology, buoyancy, fertilization success (KjÖrsvik et al 1990;Bromage 1995;Brooks et al 1997) and biochemical composition such as lipid biochemistry (Sargent 1995;Pickova, Dutta, Larsson & Kiessling 1997;Nocillado, Pena£orida & Borlongan 2000;Tveiten, Jobling & Andreassen 2004;Penney, Lush, Wade, Brown, Parrish & Burton 2006), protein and amino acids (Srivastava & Brown 1992;Nocillado et al 2000) or vitamins (Maeland, Ronnestad & Waagbo 2003;Palace & Werner 2006).…”

Evaluating quality of Nile tilapia (Oreochromis niloticus) eggs and juveniles from different commercial hatcheries

“…Biochemical composition of juveniles can be influenced by age, sex, season and environmental conditions, such as diet (Penney et al, 2006). In our study, better growth occurred in juveniles having the highest content of carbohydrates (H2 group).…”

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“…Photoperiod manipulation experiments have not demonstrated an effect on fertilization rate or egg survival in rainbow trout (Bromage et al, 1984) and sea bass (Carrillo et al, 1989), but photoperiod manipulations that compress the interval between successive spawnings may negatively affect hatching success in sea bass (Mananos et al, 1997) and increase variability in viability among egg batches in sole (Devauchelle et al, 1988). Also, compression of the interval between successive spawning by photoperiod manipulation negatively impacts both number of eggs produced and individual egg size in cod irrespective of the photoperiod manipulation technique used (Penney et al, 2006). These findings are parallel with the obtained results from this study that photoperiodic manipulation of spawning time was significantly decreased of the egg diameter in D. dentex than natural spawning time.…”