Microstructural comparison of pit organ between Hybrid sturgeon and Chinese sturgeon Acipenser sinensis

The present study was conducted to investigate the distribution of pit organ in the critically endangered Chinese sturgeon (Acipenser sinensis), the similarities and differences in the microstructure of pit organ between Hybrid sturgeon and Chinese sturgeon, and to provide a histological basis for studying the pit organ in sturgeon species. We used hematoxylin-eosin (HE) staining, nissl staining, multi-layer fine scanning, and scanning electron microscopy to compare and analyse the microstructure of pit organ between Hybrid sturgeon and Chinese sturgeon. The results showed that the structure of pit organ of Hybrid sturgeon and Chinese sturgeon are similar. The distribution density of pit organ in different parts of Chinese sturgeon was different, and the density of pit organ on the ventral surface of the snout was the highest. Scanning electron microscopy revealed that the pit organ of Hybrid sturgeon and Chinese sturgeon were densely packed and about 500-1000 mu m wide. Nissl staining revealed that more peripheral nerves are distributed under the sensory and support cells of the pit organ. Based on previous research and our results, the increase in electrical receptivity of sturgeons with individual development is not only due to the increase in the number of inductive receptors, but may also be related to the increase in the width of the pit organ.