Malachite green and leucomalachite green in fish: a global systematic review and meta-analysis

Malachite green (MG), an antibiotic with antifungal activity, is illegally used in aquaculture. Given that this chemical is teratogenic and mutagenic, abstinence from intake seems to be a need for public safety. The goal of this systematic review and meta-analysis was to determine the global contamination of fishes by MG and its reduced metabolite, leucomalachite green (LMG), in a number of marine and farmed fish species. For literature published prior to January 2022, several databases (Web of Science, PubMed, and Scopus) were investigated. In total, 20 publications (10 countries, 724 samples) achieved the criteria for inclusion. The overall average MG and LMG concentrations were 0.48 (95% CI: 0.47, 0.49 µg kg −1 ) and 0.59 (95% CI: 0.39, 0.79 µg/kg −1 ), respectively. Eel ( M. albus ) 15.50 (95% CI: (14.39, 45.39 µg kg −1 ) and eel ( A. anguilla ) 4.46 (95% CI: 1.23, 7.69 µg kg −1 ) had the greatest contamination of MG and LMG, according to the effect size, respectively. Warm-water fish had a concentration of 2.591 (95% CI: 2.25, 2.93 µg kg −1 ) while cold-water fish had a concentration of 1.55 (95% CI: 0.25, 2.84 µg kg −1 ). Fish containing medium-fat level of 1.86 (95% CI: 1.27, 2.44 µg kg −1 ) and high-fat content of 1.10 (95% CI: 0.93, 1.26 µg kg −1 ) had accumulate MG and LMG in their tissues, respectively. As a result, total MG observed in countries including China, Iran, and the Netherlands was higher than authorized (2 µg kg −1 ). The toxicity of MG and LMG demands more monitoring, especially in countries where these chemicals’ residues are significant. Graphical Abstract