Combined Effects of Toxic Metals and Oxidative Stress on the Development and Health of Sea Trout (Salmo Trutta L.).

Abstract

Background/aims: Contaminants in the environment pose a considerable threat to biodiversity, ecological balance, and the health of both wildlife and humans, particularly through the transfer of these harmful substances via fish in the food chain.

Methods: This study focused on the developmental stages of sea trout (Salmo trutta L.) in both riverine and Baltic Sea environments, with the aim of exploring how chemical element accumulation influences oxidative stress biomarkers in these species.

Results: The findings revealed notable age- and tissue-specific patterns in the accumulation of chemical elements in sea trout. Specifically, higher levels of lead (Pb), arsenic (As), mercury (Hg), and tin (Sn) were detected in the muscle tissues of adult trout, while cadmium (Cd) primarily accumulated in the gills, particularly in smolts. These results underscore the influence of both age and tissue type on the bioaccumulation of contaminants in the trout, highlighting how the accumulation of toxic elements contributes to increased oxidative stress in the fish. This oxidative stress, reflected by increased lipid peroxidation (TBARS) and carbonyl derivatives of oxidatively modified proteins, was closely related to the presence of contaminants such as Cd, Pb, As, Hg, and Sn. Gills, which are directly exposed to waterborne pollutants, exhibited significantly higher levels of oxidative damage compared to muscle tissue, consistent with the greater accumulation of metals in this organ. Despite higher total antioxidant status (TAS) in muscle tissue, both muscle and gill tissues of adult trout showed signs of considerable oxidative stress, indicating the cumulative effects of prolonged exposure to these contaminants.

Conclusion: The study highlights the detrimental consequences of chemical element contamination on the health of trout, with a particular emphasis on oxidative damage, and calls for effective environmental management to protect aquatic species from the long-term effects of exposure to contaminants. Furthermore, the correlation and regression analysis conducted revealed significant patterns, demonstrating positive correlations between the accumulation of Cd, Pb, and As in the gills of adult trout, and between Pb and oxidative stress markers in smolts. Additionally, the analysis indicated that mercury contributes significantly to oxidative damage.