BIOACCUMULATION OF CHROMIUM IN DIFFERENT BRAIN REGIONS OF PLECTROPOMUS LEOPARDUS DURING DIETARY EXPOSURE

Excessive intake of chromium (Cr) cause neurotoxicity to fish, though, the information on the bioaccumulation of Cr in fish brain under dietary exposure is still lacking. To evaluate the effects of dietary Cr exposure on the brain of coral trout (Plectropomus leopardus), fish were fed with a gradient levels of organic Cr (as chromium picolinate (CrPic)) and inorganic Cr CrCl₃ (Cr(Ⅲ), K₂Cr₂O₇ (Cr(Ⅵ)) at 0, 10, 50, and 250 mg/kg for 66 days. Samples were collected to measure Cr accumulation in hypothalamus, forebrain, midbrain, hindbrain regions of brain at 7, 12, 18, 40 and 66 days using atomic absorption spectrometry (AAS). The results showed that Cr bioaccumulation in the four brain tissues increased significantly from day 7 to day 40, but decreased significantly after day 66 under both organic and inorganic Cr treatment. However, the total bioaccumulated Cr in four regions of brain did not increase with the increasing dietary Cr level and exposure time, indicating a dose- and time-independent pattern. The accumulated amount of Cr in the brain after dietary exposure followed the order CrPic > Cr(Ⅵ) > Cr(Ⅲ). These findings demonstrated that the dietary organic Cr had significantly higher bioaccumulation than inorganic Cr, providing a theoretical knowledge for further evaluation of the toxic effect of form-specific Cr in food on central nervous system and evaluation of its toxicological mechanism.