Soy lecithin supplementation modulates hepatic lipid metabolism in Nile tilapia reared at low temperature: a lipidomic approach

Abstract In fish, lipid metabolism is highly sensitive to low temperatures, influencing their capacity to adapt to thermal stress. This study evaluated the effects of dietary soybean lecithin on the hepatopancreas lipid profile of Nile tilapia ( Oreochromis niloticus ) reared at a suboptimal temperature (22°C). Juvenile fish (12.22 ± 0.09 g) were fed diets containing 0, 21, 43, or 64 g kg −1 of soybean lecithin for 90 days. Lipid composition of hepatopancreas was analyzed using gas chromatography (GC), flow injection analysis mass spectrometry (FIA-MS), and liquid chromatography–tandem mass spectrometry (LC–MS/MS). Soy lecithin supplementation significantly altered hepatic lipid profiles, promoting a linear increase in n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), particularly docosahexaenoic acid (DHA), which is essential for maintaining membrane fluidity under cold stress. Multiplatform lipidomic analyses revealed clear distinctions in lipid profiles among treatments. Pathway enrichment analysis highlighted significant modulation of glycerophospholipid and glycerolipid metabolism, key pathways for membrane structure and energy regulation. Notably, ether lipid and inositol phosphate metabolism were also affected, suggesting potential roles in signaling and stress adaptation. Additionally, there was a higher intensity of sterols in the liver of fish fed the higher doses of lecithin. These findings demonstrate that soybean lecithin enhances specific lipid pathways associated with membrane remodeling and metabolic resilience in Nile tilapia under thermal stress. The application of comprehensive lipidomics provided detailed insights into the dietary modulation of hepatic lipid metabolism, reinforcing the value of phospholipid-rich ingredients for improving fish robustness in suboptimal rearing conditions.