EFFECT OF EDTA SUPPLEMENTATION ON GILTHEAD SEABREAM ALLERGENICITY; A PROTEOMICS APPROACH

Food allergies are a worldwide rising problem and occur when a hypersensitive immune system reacts wrongly to a specific harmless food protein. In case of fish, 95% of the allergic reactions are due to the β-parvalbumin protein, and affects 1-3% of the adult population and about 4-6% of children. This highly abundant, IgE cross-reactive and stable muscle protein has a low molecular weight of about 12 kDa and is acidic (pI ranging from 4.5-5.0). It binds specific ions like calcium and magnesium and is involved in the contraction-relaxation mechanism of muscle. Studies showed that EDTA is a calcium chelator and reduces the IgE-binding capacity of parvalbumin. The present study was conducted to produce a lower allergenic potential of this fish enriching diets with specific components.

Twenty five gilthead seabream were reared in triplicate (initial body weight of 208.0 ± 2.95 g) during 98 days in natural flow-through seawater at the Ramalhete research station. Fish were fed twice a day, ad libitum, with experimental diets differing in the EDTA concentration (0 and 3%). Muscle and blood samples were taken during sampling after a lethal doses of 2-phenoxyethanol and frozen at -80ºC till further analysis. Proteomics and immunoblots were performed with muscle samples and cortisol levels were determined using plasma samples.  Biochemical characterization of fish was performed during 72 hours after slaughter.

Zootechnical results show a significant difference in the final body weight between the conditions (Table1).  IgE from fish-allergic patients sera showed a lower reaction to parvalbumin from fish fed the EDTA supplemented diet (Fig.1).