Histological studies on development of the digestive system of Scortum barcoo

Histological changes of the digestive system and its associated glands were studied in jade perch, Scortum barcoo from the first day(first day post-hatch, dph) to 30 dph. Specimens for this study were hatched from artificially spawned broodstock and maintained in the indoor plastic tanks(26.6-29.7 ℃). The newly hatched larvae had one big yolk sac, and their digestive tract was only a columniform diverticulum, without communication with outside. Digestive tract communication with outside in 30-hour-old larva and their mouth shut up. 2-day-old larvae’s gut started crumple and peristalsis. The intestinal had been divided into anterior intestine and posterior intestine by intestinal valve. 3-day-old larvae could be fed, the epithelial of digestive tract begun differentiation, mucous cells appeared in esophageal, pancreas and liver appeared. The nutrition of fish began transferred to the stage of mixed nutrition. In this stage, the digestive tract was differentiated into five portions: buccal-pharyngeal cavity, esophagus, stomach, anterior intestine and posterior intestine, liver and pancreas had also been formed; these organs already had initial structure and the capacity of digestion and absorption. Along with the development of larvae fish, digestive system tended to perfect. Gastric glands appeared in the stomach of 21-day-old juvenile, marking the beginning of juvenile.