Morphological studies on the gills of the European hake (Merluccius merluccius, Linnaeus, 1758)

Gill arch and raker morphology of common carp (Cyprinus carpio, Linnaeus, 1758) sampled in aquaculture system

The study aimed to investigate the morphologic aspects of common carp's gill arch and gill rakers (Cyprinus carpio, Linnaeus, 1758), an omnivore and highest-produced aquaculture species. The study used 10 common carp (395.35 ± 45.06 g) grown entirely under aquaculture conditions. The fish tissues were fixed with Glutaraldehyde (2.5%) for scanning electron microscopy and with formalin (10%) for stereomicroscopic examination. In the SEM examination, two types of taste papillae (Type II and Type III) were observed in the pharyngeal mucosa. Microridge-like structures in the epithelial layer were found to have two forms. The study findings indicate a significant decrease in gill arch lengths from cranial to caudal and a significant increase in rakers per unit area, as determined through digital calliper measurements and stereomicroscopic examinations (p < 0.05). However, there was no significant difference in measurements of gill arches and raker numbers between the bilateral symmetry of the gill arches (p > 0.05). In conclusion, it was observed that the epithelial structure on the common carp gill arch contained two types of microridge-like structures: the gill arch length decreased from cranial to caudal, and the rake density on these arches increased caudally.

Morphological investigation of the gills of the dusky grouper Epinephelus marginatus (Lowe 1834) using gross anatomy and scanning electron microscopy

The current study has designed to investigate the morphological characteristics of the gills of the dusky grouper (Epinephelus marginatus) by gross morphology, scanning electron microscopy, and morphometric analysis. The study was carried out on 10 fresh fish. The fish has four-gill arches on each side. The lengths of the first-, second-, third-, and fourth-gill arches were 5.27, 4.2, 3.2, and 2.8 cm. The gill arches carried a longitudinal band, the bases of the gill filaments, and gill rakers that varied from rectangular to circular shapes. Each gill arch had two main lateral and medial rows and two accessory rows of gill rakers in an alternative manner with each other. The dusky grouper fish had long rakers, whereas the longest one was the lateral rakers of the first arch, which were 467 and 1271.9 μm in width and length. Three types of spines appeared on the gill arches and rakers. The long spine had detected on the apex of the short rakers. Each gill arch carried on its ventral side two rows of gill filaments. The long filaments were at the middle of the gill arch, while the short ones were at the rostral end of the gill arch. The study has demonstrated the taste buds, mucous, chloride cells, and significant features of the epithelial covering of the gill arches and rakers. The morphology of the gills of the dusky grouper indicates the adaptation to their marine environment.

Ultrastructural comparison between the oral cavity floor of the juvenile and adult Epinephelus aeneus: New vision of aging development and its carnivorous adaptation

The current work is designed to give the first trial to characterize the ultrastructural lineaments of the oral cavity floor in juvenile and adult white grouper. The present work depends on 10 oral cavities floor from each age. The common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The non-protrusible elongated tongue had a clear apex, body, and root with the absence of any taste buds. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. The notched lower velum at the middle of the free border was observed in juveniles and adults. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish. The obtained findings provided essential data to aquaculture of this fish species in Egypt by determining the food particle types that are favorite to this fish. HIGHLIGHTS: The common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish.

Gross morphological and surface ultrastructural investigation on the gills of the European barracuda Sphyraena sphyraena

The present work examined 10 gill systems of European barracuda grossly and by scanning electron microscopy (SEM). Grossly, there were four pairs of the gill arches. The convex border of the gill arch carried the gills filaments, but there were abundance of spines near to its concave border and the gill rakers were absent. Laterally near to the convex border of the gill arch, SEM observations revealed that the first gill arch carried small elliptical, oval, cuboidal, and triangular groups of two shapes of spines; spearhead-like spines and canine-like spines, but the other three gill arches carried larger groups of the same shaped spines with the appearance of waterfalls. Medially near to the convex border of the first gill arch, the canine-like spines were observed only in the form of vertical rectangular groups that adhered in some areas. Laterally near to the concave border, the two shapes of spines were present in the form of longitudinal groups separated by spaces at the first gill arch, but these spaces were absent in the other three gill arches. Medially near to the concave border of the first gill arch, the two shapes of spines were presented in oval groups, while the other three gill arches were covered entirely by cuboidal groups of the two shapes of spines. The absence of the gill rakers in conjunction with an abundance of spines helps the European barracuda to control the food particles from escaping to the gill filaments to prevent its suffocation.

Gill morphology of Bagrus bayad (Forskal, 1775) using scanning electron microscopy

The work under investigation is carried out to describe the gross morphology and ultrastructure of the gills of the species Bagrus bayad grossly and with the help of scanning electron microscopy. The current work carried on ten fresh adult Bagrus bayad. Bagrus bayad is a genus of the Bagridae family. Our results revealed that the operculum opened caudoventrally. The wide interbranchial septum consisted of four transverse raised areas on each side that connected by transverse lines caudal to the base of the tongue. The gill arch is divided into long ceratobranchial and the short epibranchial clearly and formed an angle between them in the first three gill arches but in the fourth-gill arch is not clear. The first two gill arches have only lateral rackers. The first arch carried well-developed long rackers while rackers on the following rows were short. The majority of gill rackers were short as an adaptation of the carnivorous feeding habit of the Bagrus bayad. The gill arch and rackers were covered by pavement cells with chloride and mucus cells. The pavement cell surface has numerous microridges giving them the fingerprint's appearance. The gill filament's length is nearly fixed along the entire gill arch. Along the gill arch, and the gill filament carried leaf-like gill lamellae. At higher magnification, the gill filament appeared covered by irregular polygonal cells that have concentric microridges.

A focus on the gross morphological and ultrastructural characteristics of the oesophagus and stomach of Eurasian common moorhen (Gallinula chloropus chloropus, Linnaeus 1758)

The present work was the first attempt to examine the oesophagus and stomach of the Eurasian common moorhen grossly and by SEM. The oesophagus was composed of long cervical and short thoracic parts. The longitudinal folds of the cervical part were narrower than that of the thoracic part, while the depressions between these folds were shallower and wider in the cervical part. On the epithelial surface of the oesophagus, micropapillae were present and they were numerous and smaller at the level of the cervical part. The openings of the oesophageal glands were circular at the level of the cervical part and oval to elliptical at the thoracic part. The crop was absent. The proventriculus was fusiform in shape; its mucosa was arranged in several, concentrically arranged mucosal folds connected with each other by transverse folds. The proventriculus glands were oval and opened by raised papillae on the epithelial surface. The gizzard was oval; its mucosa was lined by a horizontal layer of cuticle appeared like the fish scales, while the vertical part of the cuticle appeared as thin rods. The folds of the oesophagus are functioning for the expansion for the passage of the food particles. The tunica musculosa of the gizzard was thick to help in grinding of the food particles.