Abstract
The objective of the present study was to compare the effectiveness of dietary marine phospholipids (MPL) obtained from krill and soybean lecithin (SBL) on the rearing performance and development of seabream (Sparus aurata) larvae. Larvae were fed from 16 to 44day posthatching (dph) five formulated microdiets with three different levels (50, 70 and 90 gkg(-1)) of phospholipids (PL) obtained either from an MPL or from a SBL source. Larvae-fed MPL show a higher survival, stress resistance and growth than those-fed SBL, regardless the dietary PL level. Overall, the increase in MPL up to 70 gkg(-1) total PL in diet was enough to improve larval gilthead seabream performance, whereas even the highest SBL inclusion level (90 gkg(-1) PL) was not able to provide a similar success in larval growth or survival. Inclusion of SBL markedly increased the peroxidation risk as denoted by the higher TBARs in larvae, as well as a higher expression of CAT, GPX and SOD genes. Moreover, SBL tends to produce larvae with a lower number of mineralized vertebrae and a lower expression of osteocalcin, osteopontin and BMP4 genes. Finally, increasing dietary MPL or SBL lead to a better assimilation of polyunsaturated fatty acids in the larvae, n-3HUFA (especially 20:5n-3) or n-6 fatty acids (especially 18:2n-6), respectively. In conclusion, MPL had a higher effectiveness in promoting survival, growth and skeletal mineralization of gilthead seabream larvae in comparison with SBL.