Gill morphology and morphometry of the facultative air‐breathing armoured catfish, Corydoras paleatus, in relation on aquatic respiration

Abstract

The Neotropical armoured catfish Corydoras paleatus is a facultative air‐breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, it is important to analyse the gills from a morphological aspect and its dimensions in relation to body mass with reference to aquatic respiration. For that, the gills were analysed using a stereoscopic microscope for morphometric studies, and structural and ultrastructural studies were carried out to compare the four branchial arches. Furthermore, two immunohistochemical techniques were used to locate and identify the presence of a Na+/K+ pump. The characterization of the potential for cell proliferation of this organ was assessed using an anti‐PCNA antibody. The results show that gills of C. paleatus present some characteristics related to its diet and lifestyle, such as the limited development of gill rakers and the abundance of taste buds. In addition, other special features associated with the environment and bimodal breathing were observed: scarce and absent mucous cells (MCs) in the gill filaments and branchial lamellae, respectively, and the localization of mitochondria‐rich cells (MRCs) covering the basal third of the branchial lamellae, which reduces the gill respiratory area. A peculiar finding in the gill epithelium of this armoured catfish was the presence of mononuclear cells with sarcomeres similar to myoid cells, whose functional importance should be determined in future studies. Finally, in C. paleatus, the interlamellar space of gill filaments is an important site for cell turnover and ionoregulation; the latter function is also performed by the branchial lamellae.

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

“…The current research has determined that C. carpio possesses four‐gill arches on either side of its body. These gill arches are arranged in a lateral to medial sequence, similar to the majority of teleost fishes; S. luridus , P. pagrus , B. boops (Alsafy, Seif, et al, 2022), Epinephelus marginatus (Alsafy & El‐Gendy, 2022), Sphyraena sphyraena (Hanafy, 2022), Chaca chaca (Mistri et al, 2016), Corydoras paleatus (Plaul et al, 2021), Siniperca chuatsi (Tran et al, 2022), Labeotropheus fuelleborni , Tropheops (Zogbaum et al, 2021). They are designated as the first, second, third and fourth gills.…”

“…pagrus, B. boops (Alsafy, Seif, et al, 2022), Epinephelus marginatus (Alsafy & El-Gendy, 2022), Sphyraena sphyraena (Hanafy, 2022), Chaca chaca (Mistri et al, 2016), Corydoras paleatus (Plaul et al, 2021), Siniperca chuatsi (Tran et al, 2022), Labeotropheus fuelleborni, Tropheops (Zogbaum et al, 2021). They are designated as the first, second, third and fourth gills.…”

Ovarian changes and development of the branchial placenta occurring in Jenynsia lineata (Cyprinodontiformes, Anablepidae)

“…Finally, the samples were passed through an increasing series of graded alcohol and xylene, and mounting. Negative control sections were prepared by omitting the primary antibody while positive control sections were samples of mammalian intestine (Plaul et al, 2021).…”

“…Finally, the samples were passed through an increasing series of graded alcohol and xylene, and mounting. Negative control sections were prepared by omitting the primary antibody while positive control sections were samples of mammalian intestine (Plaul et al, 2021). Histological sections were observed with a Leica DM1000 Microscope and digital photomicrographs were taken using an image capture system (Leica ICC50W).…”