Characterization and modulation of fish allergenicity towards the production of a low allergen farmed fish

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Publication . Schrama, Denise; Rodrigues, P. L.; Kuehn, Annette; Engrola, Sofia Alexandra Dias

Food allergies are a common health problem worldwide, triggering an abnormal immune response. Fish belongs to the top nine of most allergenic foods, among milk, eggs, shellfish, tree nuts, peanuts, wheat, soybeans and the most recently added sesame. The continuing increase of aquaculture production and the relatively easy access to fish worldwide, contribute to increased fish consumption which result in higher prevalence of allergies. The main allergen in fish, responsible for up to 70-95% of the allergic reactions, is a small and stable calcium-binding muscle protein named parvalbumin. This thesis was focused on parvalbumin in two economically important fish species for Southern Europe aquaculture, namely gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax). Chapter 2 characterized this allergen, determining its structure by circular dichroism, sequencing its amino acids by mass spectrometry and analyzing its stability after fish digestion or processing. Results showed that parvalbumin represents a higher content of α-helices and some β-sheets in its secondary structure, at room temperature. Parvalbumins detection reduced throughout gastrointestinal digestion, and also several processing techniques, like salting, steaming and autoclaving showed a significant reduction (p<0.05) in parvalbumins detectability. In Chapter 3, a questionnaire conducted in Portugal was performed to evaluate consumers’ willingness to pay for low allergenic fish. Results showed that not only half the consumers were willing to pay extra, but also suggested that this was explained by the presence of fish allergies in the family and by the fish unique characteristics and quality. For the modulation of fish allergenicity Chapters 4.1, 4.2 and 4.3 analyzed this possibility by the supplementation of fish diets with additives like creatine and ethylenediamine tetraacetic acid (EDTA). Results showed a 50% reduction in fish-allergic serum Immunoglobulin-E (IgE)- reactivity when 3% EDTA was supplemented in gilthead seabreams diet. This promising result showed the possibility to modulate parvalbumin in order to decrease its allergenicity.

2023-04-18Doctoral thesis

Open access

Fish allergenicity modulation using tailored enriched diets—Where are we?

Publication . Schrama, Denise; Czolk, Rebecca; Raposo de Magalhães, Cláudia; Kuehn, Annette; Rodrigues, Pedro

Food allergy is an abnormal immune response to specific proteins in a certain food. The chronicity, prevalence, and the potential fatality of food allergy, make it a serious socio-economic problem. Fish is considered the third most allergenic food in the world, affecting part of the world population with a higher incidence in children and adolescents. The main allergen in fish, responsible for the large majority of fish-allergic reactions in sensitized patients, is a small and stable calcium-binding muscle protein named beta-parvalbumin. Targeting the expression or/and the 3D conformation of this protein by adding specific molecules to fish diets has been the innovative strategy of some researchers in the fields of fish allergies and nutrition. This has shown promising results, namely when the apo-form of beta-parvalbumin is induced, leading in the case of gilthead seabream to a 50% reduction of IgE-reactivity in fish allergic patients.

2022Journal article

Open access

Transcriptomic changes behind Sparus aurata hepatic response to different aquaculture challenges: An RNA-seq study and multiomics integration

Publication . Raposo de Magalhães, Cláudia; Sandoval, Kenneth; Kagan, Ferenc; McCormack, Grace; Schrama, Denise; Carrilho, Raquel; Farinha, Ana Paula; Cerqueira, Marco; Rodrigues, Pedro

Gilthead seabream (Sparus aurata) is an important species in Mediterranean aquaculture. Rapid intensification of its production and sub-optimal husbandry practices can cause stress, impairing overall fish performance and raising issues related to sustainability, animal welfare, and food safety. The advent of next-generation sequencing technologies has greatly revolutionized the study of fish stress biology, allowing a deeper understanding of the molecular stress responses. Here, we characterized for the first time, using RNA-seq, the different hepatic transcriptome responses of gilthead seabream to common aquaculture challenges, namely overcrowding, net handling, and hypoxia, further integrating them with the liver proteome and metabolome responses. After reference-guided transcriptome assembly, annotation, and differential gene expression analysis, 7, 343, and 654 genes were differentially expressed (adjusted p-value < 0.01, log2|fold-change| >1) in the fish from the overcrowding, net handling, and hypoxia challenged groups, respectively. Gene set enrichment analysis (FDR < 0.05) suggested a scenario of challenge-specific responses, that is, net handling induced ribosomal assembly stress, whereas hypoxia induced DNA replication stress in gilthead seabream hepatocytes, consistent with proteomics and metabolomics' results. However, both responses converged upon the downregulation of insulin growth factor signalling and induction of endoplasmic reticulum stress. These results demonstrate the high phenotypic plasticity of this species and its differential responses to distinct challenging environments at the transcriptomic level. Furthermore, it provides significant resources for characterizing and identifying potentially novel genes that are important for gilthead seabream resilience and aquaculture production efficiency with regard to fish welfare.

2024-03Journal article

Open access

Effect of creatine and EDTA supplemented diets on European seabass (Dicentrarchus labrax) allergenicity, fish muscle quality and omics fingerprint

Publication . Schrama, Denise; Raposo de Magalhães, Cláudia; Cerqueira, Marco; Carrilho, Raquel; Farinha, Ana Paula; Costa, Ana Rosa da; Gonçalves, Amparo; Kuehn, Annette; Revets, Dominique; Planchon, Sébastien; Engrola, Sofia; Rodrigues, Pedro

The relatively easy access to fish worldwide, alongside the increase of aquaculture production contributes to increased fish consumption which result in higher prevalence of respective allergies. Allergies to fish constitute a significant concern worldwide. beta-parvalbumin is the main elicitor for IgE-mediated reactions. Creatine, involved in the muscle energy metabolism, and ethylenediamine tetraacetic acid (EDTA), a calcium chelator, are potential molecules to modulate parvalbumin. The purpose of this study was to test creatine (2, 5 and 8%) and EDTA (1.5, 3 and 4.5%) supplementation in fish diets to modulate beta-parvalbumin expression and structure and its allergenicity in farmed European seabass (Dicentrarchus labrax) while assessing its effects on the end-product quality. Fish welfare and muscle quality parameters were evaluated by plasma metabolites, rigor mortis, muscle pH and sensory and texture analysis. Proteomics was used to assess alterations in muscle proteome profile and metabolic fingerprinting by Fourier transform infrared spectroscopy was used to assess the liver metabolic profile. In addition, IgE-reactivity to parvalbumin was analysed using fish allergic patient sera. Metabolic fingerprinting of liver tissue revealed no major alterations in infrared spectra with creatine supplementation, while with EDTA, only absorption bands characteristic of lipids were altered. Comparative proteomics showed up regulation of (tropo) myosin and phosphoglycerate mutase 2 with Creatine supplementation. In the case of EDTA proteomics showed up regulation of proteins involved in cellular and ion homeostasis. Allergenicity seems not to be modulated with creatine or EDTA supplementation as no decreased expression levels were found and IgE-binding reactivity showed no quantitative differences.

2022Journal article

Restricted access