Cadmium‐induced changes in gill morphology of zebrafish, Brachydanio rerio (Hamilton–Buchanan), and rainbow trout, Salmo gairdneri Richardson

Abstract

Freshwater zebrafish and brackish water rainbow trout were exposed to different concentrations of cadmium for up to 6 weeks. The gill morphology was examined by light and electron microscopy, and a morphometric analysis was performed. The morphometric study of the secondary lamellae revealed an increase in the portion exterior to the basal lamina, resulting in an increased diffusion distance, after exposure to cadmium concentrations of IOpgl-' and above. In both species this was due to an increase in volume of the non-tissue spaces of the secondary lamellar epithelium. Furthermore, the water space between neighbouring secondary lamellae was clearly reduced. Morphological examination revealed some gross alterations compared with control fish. These initially consisted in curling of the secondary lamellae and finally resulted in local teleangiectasia. Partial lifting of the secondary lamellar epithelium from the pillar cells resulted in large non-tissue spaces which were invaded by leucocytes. The first sign of degeneration was observed in the chloride cells, which were characterized by a dispersed cytoplasm and a smooth apical plasma membrane.

Structural changes in seawater-adapted rainbow trout (Oncorhynchus mykiss Walb.) gills

“…obs.). A similar swelling of the rainbow trout branchial larnellae and increased intracellular spaces was observed (Karlsson-Norrgren et al 1985) under exposure to toxic substances ( cadmium).…”

Cellular responses in the skin of the trout (Oncorhynchus mykiss) exposed to temperature elevation

“…Migration of leucocytes is also seen commonly in the gill epithelium in response to different water pollutants and low water pH (Mallatt, 1985;Karlsson-Norrgren et al, 1985;Wendelaar Bonga & Lock, 1992). The migration of leucocytes into external epithelia may, at least partially, explain the leucopenia observed in stressed fish (Pickering & Pottinger, 1987;Maule & Schreck, 1990).…”

Effect of ambient and dietary cadmium on pavement cells, chloride cells, and Na+/K+-ATPase activity in the gills of the freshwater teleost Oreochromis mossambicus at normal and high calcium levels in the ambient water

“…Together with the absence of mortality and the clear signs of recovery of the gill damage this indicates that the conditions used were not exceptionally stressful even though rather high levels of cadmium exposure were used. In this respect tilapia is more resistant to cadmium than zebrafish and brown trout are (Karlsson-Norrgren et al, 1985). The recovery of tilapia was likely caused by induction of metallothionein-like proteins in the gill tissue (see Fu et al, 1990).…”

“…Gill damage and structural changes caused by water-borne cadmium have been reported for several fish species (Bilinski and Jones, 1973;Eisler and Gardner, 1973;Gardner and Yevich, 1970;Voyer et al, 1975;Karlsson-Norrgren et al, 1985). Simi lar alterations of the gills have been observed in fish exposed to other toxic metals such as mercury (Lock et al, 1981;Naidu et al, 1983), copper (Gupta and Rajbanshi, 1981), zinc (Crespo et al, 1981), chromium (Van de Putte et al, 1982), tributyltin (Pinkey et al, 1989) and, in acidic waters, aluminium (Youson and Neville, 1987).…”