Histological evidence of accumulation of iron in postlarvae of red abalone, Haliotis rufescens

摘要

The effect of iron on abalone postlarvae (Haliotis rufescens) was investigated in a controlled-culturing system. Three iron concentrations (0.15, 1.5 and 15?mg?L?1 of Fe) and a control (no iron added) were used to culture H. rufescens postlarvae while being fed the diatom Navicula inserta over 10?days. Results indicate that H. rufescens postlarvae accumulate iron granules in the stomach, digestive gland and mantle, but not in the gills or other tissues. The number and diameter of iron granules in tissues increased with increasing iron concentration in the culturing environment. The iron accumulation is assumed to have been acquired in the digestive system through the iron-enriched diatom feed and in the mantle through subcutaneous iron transfer. The lack of iron granules in the gills suggests that iron is not absorbed through the respiratory system, as is the case for many filter feeding bivalves. Exposure to the highest iron concentration (15?mg?L?1) resulted in tissue abnormalities where granules accumulated, and may have significantly affected the health of H. rufescens postlarvae. These findings provide valuable information for the regulation of appropriate iron levels within aquaculture settings and highlights the importance of monitoring iron levels within abalone larval culturing environments.