eChapter Name: Histological Alterations in Gill, Kidney and Liver of Fish as a Diagnostic Tool for Ecotoxicological Research
9789358879315
eBook Name: AQUACULTURE TECHNOLOGICAL ADVANCEMENTS
by Tiyasha Bhattacharya, Avishek Bardhan
1. Introduction
Human activities significantly lead to deterioration of ecological systems, affect individual organisms, and disrupt natural ecosystems. The rise in foreign compounds, such as heavy metals and pesticides, in aquatic ecosystems due to human activities has spurred extensive global research efforts (Wester et al., 2002). The Union’s Water Framework Directive (WFD) mandates monitoring programs to assess water body health. In environmental studies, understanding the impact of contaminants on aquatic life requires a multifaceted approach (Ullah and Zorriehzahra, 2015). Biomarkers that observe biological responses at various levels offer crucial insights into the presence and bioavailability of toxicants, complementing traditional methods (Yancheva et al., 2016). These indicators, termed early warning signals, are vital for evaluating exposure, effect mechanisms, susceptibility to contaminants, and enhancing predictive models (Yancheva et al., 2016). Integrating biomarkers into ecological studies provides a holistic understanding of environmental stressors and their implications in aquatic organisms.
2. Why is fish used as a model organism in ecotoxicological studies?
According to the Water Framework Directive (WFD), fish serves as a crucial indicator of river ecological status (Ullah and Zorriehzahra 2015). Their diverse sizes, ages, trophic levels, and sensitivity to various toxicants make them excellent indicators of water contamination (Wester et al., 2002). Fish adapt their metabolic functions in response to environmental changes, which makes them valuable in toxicological research. Monitoring sentinel fish species is a widely accepted method for assessing toxicant accumulation and its impact on human health (Wester et al., 2002). Fish, with their developed osmoregulatory, endocrine, nervous, and immune systems, are preferred to invertebrates in toxicological studies. Fish can absorb toxicants through both waterborne and dietary exposure, allowing the evaluation of contaminant transfer through the food chain. Key tissues for ecological, toxicological, and pathological studies in teleost fish include the gills, liver, and kidney because of their high metabolic activity and tendency to accumulate toxicants (Wester et al., 2002).