Session: Parallel session 4 - Spatial OMICs and MS Imaging

EFFECTS OF PARENTAL AND EARLY LIFE FEEDING WITH SUSTAINABLE FISHMEAL THROUGHT QUANTITATIVE LA-ICPMS IMAGING OF SELENIUM AND MERCURY IN RAINBOW TROUT FRY TISSUES

Laurie LABEYRIE¹, Germain VALLVERDU¹, Stéphanie FONTAGNÉ-DICHARRY², Sandra MOUNICOU¹

¹IPREM UMR 5254 CNRS/UPPA, Pau, France
²INRAE, Universite de Pau et des Pays de l’Adour, E2S UPPA, NUMEA, Saint-Pée-Sur-Nivelle, France

Introduction

The development of more sustainable feeding practices in aquaculture prompts to investigate alternative ingredients to fishmeal sourced from wild-captured forage fish. Plant products are considered, but require selenium (Se) supplementation to maintain farmed fish antioxidant status. Tuna by-products are attractive for their high Se content but their potential mercury (Hg) presence could reduce the beneficial properties of Se. Localisation of Se and Hg in tissues helps to understand their metabolism and effects. Our objective was to develop a LA-ICPMS imaging methodology for Se and Hg quantitative localization in tissues to assess the impact of parental and direct dietary supplementation with Hg and Se in tuna by-products and plant-based diets.

Methodology

Two calibration strategies were set-up for Se, Hg, Cu and Zn LA-ICPMS quantitative imaging in sections of trout fry. One method based on polymer films (dextran) allowed internal standardization while the other relied on 2 types of matrix-matched-standards (MMS). Quantitative imaging was performed in sections of 3-week fry fed directly or whose parents were fed either a plant or tuna by-product meal-based diet, supplemented or not with selenomethionine and/or methylmercury.

Results and conclusions

Linear regressions with R²>0.994 were obtained for Se, Cu, Zn for both methods while linear regression for Hg was achieved with MMS only. Polymer films method reached lower LODs than MMS method. The 2 methods agreed for Se, Cu and Zn quantification depending on the standards matrix. Imaging data showed that Se intake favoured hepatic Se level and decreased renal Hg level. Se and/or Hg intake increased their concentration in all fry tissues, especially in liver, kidney, muscle and intestine. Mercury transfer from parents to offspring was weak while direct dietary Hg enhanced its accumulation in kidney. High Se levels in Hg-containing diets for fry reduced renal Hg level, suggesting a Se-Hg antagonism.