Histological study on development of the digestive system of longfin batfish (Platax teira)

Abstract

The ontogeny of the digestive tract in Platax teira was studied by means of optical microscopy from hatching to 30 days post-hatching. Collect fertilized eggs from P. teira broodstock, fertilize the eggs to hatch in hatching net bags, and rear the larvae in higher-place ponds. Observe the morphology and structure of the digestive tract of larvae 1-30 days post-hatching using tissue slicing technique. The results showed that the oral cavity of the larvae was closed and had not yet begun to differentiate at 1day post-hatching. Its digestive tract was close to the abdominal wall, and the yolk sac was completely dyed dark red. At 4 days post-hatching, the oropharyngeal cavity, esophagus, and stomach of the larvae had been communicated, and their oral cavity opened and food intake begins, entering the mixed period of endogenous nutrition and exogenous nutrition. Thereafter, the yolk sac gradually decreased to disappear, the esophagus, stomach, and intestines continued to differentiate, and their functions gradually improved. During 25-30 days post-hatching, the structure of the digestive tract of the larvae didn’t change much. Due to the increase in the size of the larvae, most changes in the digestive system are related to the complexity of the tissues and the size of the organs. Specifically, the number of mucosal folds and cells in the esophagus and intestine increases, and the gastric glands and pits in the stomach increase. The number of mucous membrane folds, mucosal epithelial cells and gastric glands in the digestive tract increase with the growth of the larvae, indicating that the development of the digestive system of P. teira is consistent with the growth of larvae, morphological development, feeding, metabolism and other functions consistently, its developmental stage is also adapted to the stages of the early development stage of P. teira.