ZEBRAFISH ITALIAN MEETING 2022 – Proceedings

Food dyes are widely used additives, and their harm to human health has been clearly recognized in recent decades. As a result, a significant effort has recently been made to introduce vegan substitutes prepared with fruit and vegetables. Although this category of dyes is widely used, not much information is available on their possible effects on aquatic and terrestrial ecosystems once released as waste into surface waters. The toxicity of artificial dyes on target organisms has been demonstrated. Our previous works highlighted the toxic effect of non-vegan food dyes on animal and plant model organisms [1]]. It is known that artificial food colors can induce hyperactivity and movement alterations [2,3]. To understand if vegan dyes can also have similar effects on locomotion, we exposed Danio rerio larvae to three common red food colors, a red vegan (VEG) preparation, the cochineal E120 and the artificial E124. We measured larvae motility and performed light and electron microscopy analyses of muscle. The larvae's average speed, acceleration, and length travelled significantly increase in the E124 treatments compared to the controls and the other two red dyes treatments. In semithin sections, muscles never show alterations in the morphology and/or in the general organization while metachromasia significantly decreases in connective septa exposed to E120 and E124. In E124 samples, TEM investigations also show asynchrony in fiber contraction, marked alteration in myofilaments organization and a significant vesiculation of mitochondria. In conclusion, our data highlight the marked toxicity of E124 for Danio rerio muscles and indicate that natural substitutions E120 and vegan red are not entirely harmless.