Biochemical composition and performance of Atlantic cod (Gadus morhua L.) eggs and larvae obtained from farmed and wild broodstocks

Farming of Atlantic cod, Gadus morhua L., has been facing several challenges lately. Biological issues such as differences in egg quality and lack of high quality larvae are considered as prominent limiting factors. The aim of this study was to compare fertilization and hatching rates, incidence of malformed larvae at hatching, larval viability (high-salinity stress and starvation tolerance tests) and the biochemical profile (proteins, amino acids, lipids, fatty acids and minerals) between eggs produced from wild and farmed broodstocks. Twenty-five batches of eggs from farmed broodstock (FB) and 27 egg batches from wild broodstock (WB) were collected during the reproductive season. Fertilization and hatching rates were significantly higher in WB group (91 +/- 3% and 86 +/- 3%, respectively) than in FB (75 +/- 3% and 66 +/- 3%, respectively). In high-salinity stress test, WB larvae survived for a significantly longer time than FB larvae. No differences between egg batches from the two broodstocks were observed in starvation tolerance tests, incidence of malformed larvae at hatching, as well as in the total content of proteins, lipids, fatty acids, zinc, and calcium concentrations. Regarding fatty acids, FB eggs had significantly higher levels of C16:0, C18:0, C18:2n - 6, C18:3n - 3, C18: 3n - 6, C20:4n - 6, C20n:5n - 3, C22:5n - 3 and C22:5n - 6, whereas WB eggs had significantly higher levels of C14:0, C16:1n - 7, C18:4n - 3, C20:4n - 3, C22: 6n-3 and C24:1n - 9. As for the amino acid profile, WB eggs had significantly higher levels of aspartic acid, serine, glycine, threonine, taurine and leucine, while FB eggs had significantly higher levels of proline, tryptophan, phenylalanine and arginine. The concentrations of minerals such as copper and phosphorus were significantly higher in WB eggs, whereas in FB eggs iron concentration was significantly higher. Overall, the biological parameters indicated that egg and larvae originating from WB were of superior quality than those from FB. The information on the biochemical profile may be useful in improving the quality of broodstock feeds for Atlantic cod. (C) 2011 Elsevier B.V. All rights reserved.