Abstract
The aim of the present study was to study the effect of different dietary phospholipid sources derived from krill (KPL) and soybean lecithin (SBL) with different levels of phosphatidylcholine (PC) and n-3 HUFA on the performance and histological changes in intestine and liver of seabream larvae. Larvae (16 dph) were fed for 1 month five formulated microdiets (control, 7KPL, 9KPL, 7SBL, and 9SBL). The larvae fed dietary KPL rich in phosphatidylcholine and n-3 PUFA showed better performance in terms of survival and growth than those fed SBL. The inclusion of KPL up to 7% PL (3.8% PC and 7.7% n-3HUFA) in diet was sufficient enough to improve significantly the larval survival and growth compared to the highest dietary 9% PL of SBL (2.5% PC and 5.6% n-3HUFA); in addition, the larvae fed KPL showed higher content of n-3HUFA specially EPA and DHA. The larval survival and total length were positively correlated to dietary PC and n-3HUFA contents. But, inclusion of SBL was associated with a high relative accumulation of lipid droplets in the supranuclear zone of the enterocytes and in hepatocytes compared to larvae fed dietary KPL. The intestinal and hepatic steatosis was negatively correlated to dietary PC content. In conclusion, dietary 7% KPL (3.8% PC and 7.7% n-3 HUFA) improved significantly the larval survival and growth and decreased significantly the intestinal and hepatic steatosis compared to SBL, denoting better dietary lipid absorption, transportation, and energetic utilization.