Sublethal Toxicity of Cadmium Chloride on Tissue Glycogen Reserves in Heteropneustes fossilis

Abstract

This study looked at how cadmium chloride (CdCl₂) affects glycogen reserves in Asian stinging catfish (Heteropneustes fossilis) over two months. Fish were exposed to 75 mg/L of cadmium chloride, and researchers measured glycogen in the muscles, gills, liver, heart, and kidney at 30 and 60 days. The numbers tell a clear story: glycogen dropped in every tissue, and the heart, liver, and gills took the hardest hit. After 60 days, muscles went from 7.81 to 6.87 mg/g (a 12% drop), gills from 5.43 to 3.52 mg/g (down 35%), liver from 16.82 to 10.93 mg/g (down 35%), heart from 3.51 to 2.07 mg/g (down 41%), and kidney from 6.87 to 5.42 mg/g (down 21%). The heart always had the lowest glycogen, which means it’s especially vulnerable to the stress from cadmium. This sharp loss of glycogen shows that cadmium messes with how the fish use carbohydrates, ramps up the energy they need to detox, and probably causes some real damage to their organs. In short, even at levels that don’t kill them outright, cadmium throws the fish’s metabolism out of balance. Different organs react in their own way, but the end result is trouble for the fish’s health, growth, and overall chance to thrive—bad news for a species that matters in freshwater fisheries.