Non-targeted UHPLC-HRMS based metabolomics for the identification of nutritional variations in fish serum

The high power of new analytical techniques hold their expansion to new application fields as health research, nutrition or food safety, extremely interesting for human welfare. This widening in analytical chemistry has been supported with new non-targeted approaches as ¿omic¿ techniques. The relevance of these techniques encourages opening new perspectives in other subjects as the nutrition of farmed animals. The assessment of nutrients and energy sources that animals need to grow ensures a correct life quality for both animals and consumers. In order to ensure this quality, metabolomics are being currently explored. On the last years, NMR based metabolomics have been typically used because of its versatility, robustness, universality and elucidation power. On the other hand, their high price and maintenance cost together with a low sensitivity have raised the search for alternative methods like LC-HRMS. This hyphenated technique is considered ¿ideal¿ for this kind of research thanks to its full spectrum acquisition with high sensitivity (around ppb) from small sample quantities (microliters) of animal bio-fluids (blood, urine¿). In our case, juveniles of gilthead sea bream, one of the most important fish species in European aquaculture, were fed with four different diets. In these diets, marine derived ingredients were partially substituted by alternative plant materials in order to have more sustainable diets for fish farming. On the other hand, the potential introduction of mineral additives might also induce extraordinary nutritional-dependent effects on animals. Serum samples were treated with acetonitrile followed by centrifugation. An aliquot was directly injected in HILIC chromatography and the rest was dried and reconstituted for RP chromatography with H2O:MeOH (90:10). UHPLC-HRMS data was extracted, aligned and normalized with XCMS package and finally analyzed by multivariate analysis. Some potential biomarkers from the different experiences highlighted d