Determining the differences in effect of chromate, chromite and chromium picolinate in rainbow trout (Oncorhynchus mykiss) at environmentally relevant concentrations

Abstract

The Ring of Fire is a region in the James Bay Lowlands of northern Ontario that houses a rich deposit of chromite and is slated for mining development. The goals of this study were to better understand the relative effects of Cr6+ to Cr3+ in rainbow trout, identify potential protein biomarkers to distinguish between Cr6+ and Cr3+ exposure, and determine whether chromium picolinate (a commonly prescribed nutritional supplement) is beneficial or harmful to fish. Proteomic analysis on the fish plasma showed no difference in Cr6+ and Cr3+ exposure across all concentrations and between chromium species. Decreased abundance in proteins associated with hepatocellular carcinoma and cardiomyopathy were also observed. These proteins were Trim21, Slc8a1, Myh4 and Myh6. For all, decreased abundance is associated with adverse outcomes. We hope that this study will advance knowledge on chromium toxicity in fish and protect all that inhabit the Ring of Fire region of Canada.