The development of pharyngeal taste buds in Hucho taimen (Pallas, ۱۷۷۳) larvae

This study aims to investigate the relationship between the development of pharyngeal taste buds (TBs) and first feeding of Hucho taimen. Larvae were fed with live food (water flea and tubifex) for ۸ weeks. TBs of larval pharynx were histologically examined using light microscopy during the rearing experiment. The results showed that the first few TBs primordia were visible within the pharynx ۲۷ days after hatch (DAH), which coincides with the onset of feeding, and the first few TBs with open receptor areas appear ۴۵ DAH. TBs of pharynx were well developed ۷۶ DAH. The number and size of TBs were quantified during larval development. The average number of pharynx was ۸.۶۳±۱.۱۵, ۱۱.۲۹±۰.۵۰, ۱۴.۵۰±۱.۰۶, and ۱۷.۷۸±۰.۴۷ TBs at ۲۷, ۳۶, ۴۵, and ۷۶ DAH, respectively. The number of TBs increased in both the upper and lower pharynx. The ratio of height to width of TBs showed an increase tendency, ranging from ۰.۸۱ to ۱.۱۱. The height of TBs showed an increase tendency after ۲۹ DAH during the development. However, the width of TBs exhibited a low at ۳۵ DAH. In conclusion, the development of pharyngeal TBs coincides with the first feeding, and this should lead to a better understanding of improvement of larval rearing in H. taimen hatcheries.

Keywords:

Hucho taimen , Taste buds , Development , Pharynx , Feeding