A study of morphology and histology of the alimentary tract of Glyptosternum maculatum (Sisoridae, Siluriformes)

Abstract

2011. A study of morphology and histology of the alimentary tract of Glyptosternum maculatum (Sisoridae, Siluriformes). -Acta Zoologica (Stockholm) 92: 161-169.The structure of alimentary tract has been studied in a cold water fish Glyptosternum maculatum, an endemic teleost species of notable economic importance and with high potential for controlled rearing of the species in Tibet, by light and electron microscope. Glyptosternum maculatum has short oesophagus, large caecal-type stomach and short intestine, and the digestive tract with four layers: mucosa, submucosa, muscularis and serosa. Taste buds were found in the epithelium of lips, buccopharynx and oesophagus. The stratified epithelium of buccopharynx and oesophagus was located with numerous goblet cells. The U-shaped stomach has three parts, corresponding to mammalian cardiac, fundus and pyloric portion, lined with a single-layered columnar epithelium, and tubular gastric glands are present in cardiac and fundic portion, but absent in pyloric portion. No pyloric caeca was detected. The intestine is separated from the stomach by a loop valve. The intestine epithelium is composed of simple columnar cells with a distinct microvillus brush border and many goblet cells. Meanwhile, the intestinal coefficient was 0.898. At the ultrastuctural level, three type cells (mucous, glandular and endocrine cell) were found in the stomach, and glandular cell with a great amount of pepsinogen granules. The enterocytes of the intestinal mucosa display abundant endoplasmic reticulum, mitochondria and well-developed microvilli.

Morphological, histological and histochemical analysis of the digestive tract of Trachelyopterusstriatulus (Siluriformes: Auchenipteridae)

“…This difference between P. maculatus and T. striatulus is consistent with omnivorous feeding habits that tend KAPOOR et al (1975), they produce mucus and are primary food detectors. Trachelyopterus striatulus presented a stratified squamous epithelium with taste buds, as observed in Glyptosternum maculatum (Regan, 1905) (XIONG et al 2011). Histochemical analyses of this study showed neutral mucus, carboxylic and sulphated acids, which, according to AGRAWAL & MITTAL (1992), are important in labial epithelium lubrication and protection.…”

“…In fact, eating insects like coleopterans, as described for the species under study (DIAS et al 2005), can cause injury to the oesophageal tissue, but the epithelium protects this layer. Mucous cells were observed in the oesophageal epithelium of T. striatulus, and they reacted positively to histochemical analysis, similar to P. maculatus (GODINHO et al 1970) and T. brasiliensis (OLIVEIRA-RIBEIRO & FANTA 2000), suggesting that this action of the mucus is associated to guiding different types of prey and lubricating the food, also described by OLIVEIRA- RIBEIRO & FANTA (2000) and XIONG et al (2011). Taste buds were observed in the oesophageal epithelium of T. striatulus and in the Siluriformes I. punctatus (SIS et al 1979), T. brasiliensis (OLIVEIRA-RIBEIRO & FANTA 2000), and G. maculatum (XIONG et al 2011).…”

“…Morphological analyses of the digestive tract are essential to understand the biology of species, physiology, fish management, and conservation, as seen in important studies such as those by RODRIGUES & MENIN (2005), XIONG et al (2011), and GERMANO et al (2014. Some fish species have barbels with sensory structures, such as mechanoreceptors and chemoreceptors, which can be adapted to benthic life (GODINHO 1967, KAPOOR & BHARGAVA 1967, PARK et al 2012.…”

“…maculatum (XIONG et al 2011). According to HUMBERT et al (1984) andXIONG et al (2011), it is in the epithelial tissue where cell renewal occurs, which is important for mucosal layer maintenance, thus protecting against the invasion of pathogens as well as mechanical injuries. In fact, eating insects like coleopterans, as described for the species under study (DIAS et al 2005), can cause injury to the oesophageal tissue, but the epithelium protects this layer.…”

Histochemical differences along the intestine of Corydoras paleatus (Siluriformes: Callichthyidae)

“…Microscopically, in the great majority of fish species, intestinal wall is described by three (Çinar & Şenol, 2006) or four tunics (Olaya et al, 2007;Wilson & Castro, 2011;Xiong et al, 2011), depending on whether the tunica submucosa is considered together with the tunica mucosa or not.…”