Physiological Benefits of Dietary Lysophospholipid Supplementation in a Marine Fish Model: Deep Analyses of Modes of Action

SIMPLE SUMMARY: While lysophospholipid supplementation in animal feed mainly aims at improving fat emulsification, additional metabolic effects in fish have not been explored. The present study aimed to gain understanding of the mechanisms underlying the growth-promoting effect of lysophospholipid supplementation using a commercial product (AQUALYSO(®), Adisseo, Barbastro, Spain). Atlantic salmon was selected as the model species with the intestine and liver as target tissues. The resulting tissue interactomes revealed the putative mode of action of LPLs in salmon nutrition. In summary, the biological processes stimulated by the LPL-diet suggest a more robust digestive capacity together with better nutrient processing in the liver, favoring the conversion of nutrients into weight gain and showing a less-reactive intestine and liver condition. These nutraceutical effects would improve the ability of fish or other organisms to deal with production conditions or with modifications in the diet. ABSTRACT: Given the hydrophilic structure of lysophospholipids (LPLs), their dietary inclusion translates into a better emulsifying capacity of the dietary components. The present study aimed to understand the mechanisms underlying the growth-promoting effect of LPL supplementation by undertaking deep analyses of the proximal intestine and liver interactomes. The Atlantic salmon (Salmo salar) was selected as the main aquaculture species model. The animals were divided into two groups: one was fed a control diet (C-diet) and the other a feed (LPL-diet) supplemented with an LPL-based digestive enhancer (0.1% AQUALYSO(®), Adisseo). The LPL-diet had a positive effect on the fish by increasing the final weight by 5% and reducing total serum lipids, mainly due to a decrease in the plasma phospholipid (p < 0.05). In the intestine, the upregulated interactome suggests a more robust digestive capacity, improving vesicle-trafficking-related proteins, complex sugar hydrolysis, and lipid metabolism. In the liver, the LPL-diet promotes better nutrients, increasing several metabolic pathways. The downregulation of the responses to stress and stimuli could be related to a reduced proinflammatory state. This study on the benefits and modes of action of dietary LPLs opens a new window into fish nutrition and could be extended to other productive species.