Identification of Plasmatic Biomarkers of Foie Gras Qualities in Duck by Metabolomics

Abstract

The foie gras is an emblematic product of French gastronomy composed of waterfowl fatty liver. The organoleptic qualities of this product depend on the liver characteristics such as liver weight (LW) and technological yield (TY) at cooking. One of the main issues for producers is to classify the foie gras with high or low technological quality before cooking them. Thus the study aims at identifying biomarkers of these characteristics with non-invasive biomarkers in duck. 1H-NMR (nuclear magnetic resonance of the proton) analyses were performed on plasma of male mule ducks at different time points during the overfeeding period to obtain a large range of liver characteristics so as to identify plasmatic biomarkers of foie gras. We used two methods, one based on bucket data from the 1H-NMR spectra and another one based on the fingerprints of several metabolites. PLS analyses and Linear models were performed to identify biomarkers. We identified 18 biomarkers of liver weight and 15 biomarkers of technological yield. As these two quality parameters were strongly correlated (−0.82), 13 biomarkers were common. The lactate was the most important biomarker, the other were mainly amino acids. Contrary to the amino acids, the lactate increased with the liver weight and decreased with the technological yield. We also identified 5 biomarkers specific to LW (3 carbohydrates: glucuronic acid, mannose, sorbitol and 2 amino acids: glutamic acid and methionine) that were negatively correlated to liver weight. It was of main interest to identify 2 biomarkers specific to the technological yield. Contrary to the isovaleric acid, the valine was negatively correlated to the technological yield.

Application of Metabolomics to Identify Hepatic Biomarkers of Foie Gras Qualities in Duck

“…Moreover, the modification of amino acid metabolism in livers during the overfeeding period corroborates the evolution of amino acid metabolism in plasma of the same ducks (Mozduri et al, 2021) and other hepatic steatosis models, as it was discussed in Mozduri et al (2021).…”

“…The animal design was clearly described previously ( Bonnefont et al, 2019 ; Mozduri et al, 2021 ). Briefly, 120 male mule ducks ( Cairina moschata × Anas platyrhynchos ) were reared until 12 weeks and overfed twice a day during 6 to 12 days corresponding to 11 to 23 meals.…”

“…They were chosen to obtain equivalent means and variabilities of LW and TY in the initial and subgroup groups. The selected samples corresponded to the samples used for identifying plasmatic biomarkers ( Mozduri et al, 2021 ). The body weight, LW, and TY of the selected samples are represented in Figures 1B – D .…”

“…They were ground into fine powder. Then, their polar metabolites were extracted with a method adapted from Beckonert et al (2007) from 0.25 g of the crushed liver with methanol and dichloromethane ( Beckonert et al, 2007 ) and carefully described in Mozduri et al (2021) . The upper phases composed of water and methanol with hydrophilic metabolites were collected in new polypropylene tubes and evaporated with a vacuum concentrator (Concentrator Plus, Eppendorf, Hamburg, Germany) and stored at −80°C until 1 H-NMR analysis.…”

“…In a recent study, plasmatic biomarkers of foie gras quality (LW and TY) were identified by proton nuclear magnetic resonance ( 1 H-NMR; Mozduri et al, 2021 ). The plasmatic biomarkers are of main interest because they can bring information of foie gras quality before slaughtering the animals.…”