Branchial Chloride Cells in Larvae and Juveniles of Freshwater Tilapia Oreochromis Mossambicus

Abstract

Branchial chloride cells in the developing larvae and juveniles of freshwater tilapia, Oreochromis mossambicus, were identified and the membrane Na+/K+-ATPase was localized in situ through binding of the fluorescent dye anthroylouabain. After co-labelling of the cells with the fluorescent probes DASPMI and Con-A-FITC, the mitochondria and apical crypt in the same chloride cells were visualized using confocal laser scanning microscopy. The high density of apical crypts indicated that many chloride cells were functional. The density of branchial chloride cells in larvae 10 days after hatching was approximately 6000 mm-2. An extremely high Na+/K+-ATPase specific activity of approximately 1500 µmol Pi h-1 mg-1 was measured in the gills 10 days after hatching. With the development of secondary lamellae and hence an increase in the amount of branchial epithelial protein, a concomitant decrease in the specific activity of the enzyme in the gill tissues was observed. Total Na+/K+-ATPase activity increased markedly in the early life stages. Our data indicate that in larval stages of fish the gills form a functional ionoregulatory organ before they start functioning as a gas-exchange organ.

Salinity affects growth performance, physiology, immune responses and temperature resistance in striped catfish (Pangasianodon hypophthalmus) during its early life stages

“…Before gills are fully formed, osmoregulation in the larval stage mainly happens through the integument where a high density of ionocytes are located (Alderdice 1988;Varsamos et al 2005). In some fish species, gills are present from early developmental stages such as hatching or the yolk sac period (Coughlan and Gloss 1984;Li et al 1995;Katoh et al 2000). The development of gills coincides with functional osmoregulatory shift from skin to gills due to changes in chloride cell distributions (van der Heijden et al 1999;Katoh et al 2000;Varsamos et al 2005).…”

Influences of Salinity on Embryonic and Larval Development of Striped Catfish Pangasianodon hypophthalmus

“…It has been reported that the first appearance of branchial chloride cells was observed at 8 days post-hatch in Japanese flounder, Paralichthys olivaceus (Hiroi et al, 1998). Li et al (1995) identified chloride cells on branchial epithelia during yolk sac stages in Mozambique tilapia, Oreochromis mossambicus. These chloride cells are also observed in the membrane of the yolk sac as well as other body surfaces of embryos and larvae.…”

Differential Expression of Hypothalamic and Gill-crh System With Osmotic Stress in the Euryhaline Black Porgy, Acanthopagrus schlegelii

“…One is a multilayered filament epithelium with pavement, mucous, and mitochondria rich cells (MRCs) which is largely involved in ion exchange. Another is a bi-layered lamellar epithelium made of undifferentiated, myoepithelial-like, granular, and neuroendocrine cells involved in gas exchange between the blood and the ambient water ( Li et al, 1995 ). Versus terrestrial vertebrates, aquatic fish face a more challenging task to achieve an internal homeostasis due to the presence of ionic and/or osmotic gradients that are hostile to the body fluids of fish ( Kaneko et al, 2002 ; Kaneko and Hiroi, 2008 ).…”