Experimental investigations on the toxicity of ammonia: effects on ventilation frequency, growth, epidermal mucous cells, and gill structure of rainbow trout Salmo gairdneri

Abstract

ABSTRACT. Juvenile rainbow trout Salmo gairdneri Rich. were experimentally exposed to 0.25 mg I-' of NH3 for 4 wk. This concentration lies between those causing acutely lethal and sublethal effects. At first, significant effects from the ammonia were recorded: greatly increased ventilation frequency, reduced food intake and an associated decrease in weight gain. Subsequently, the fish adapted considerably to the toxicant. Ventilation frequency decreased, although it remained above that of controls. Food was taken up completely and there was only a minor difference in growth between exposed trout and unexposed controls. No change from exposure to the pollutant could be detected in the number of mucous cells in the epidermis. Examination of the gill structure at the end of the expenment revealed only a slight, but significant, tissue proliferation. Unexpectedly, the comparatively high ammonia concentration produced few chronic effects. Nevertheless, results indicate that the wellbeing of the experimental fish was disturbed.

Histopathological changes induced by ambient ammonia (ammonium sulphate) on the opercular linings of the catfish Heteropneustes fossilis

“…Due to the active flow of water across the gills, which is necessary for respiration, the risk that slimy secretions of the opercular epidermis will be continuously washed away is also much greater than in the case of general body skin. Exposure to various xenobiotics causes increased ventilatory movement by the operculum and a greater ventilation (water) volume which results in respiratory efficiency (Flis 1968a, b, Sausa & Meade 1977, Smart 1978, Hillaby & Randall 1979, Lang et al 1987). This aggravates the loss of slime d u e to sloughing.…”

“…However, indiscriminate use of inorganic fertilizers including ammonium sulphate, which releases ammonia (both NH3 and NH,'), has created numerous environmental hazards for fish populations (Soderberg et al 1983, Lang et al 1987, Ram & Sathyanesan 1987, Sarkar 1991, Varadachari 1992, as these fertilizers contaminate neighbouring bodies of water, where they are mixed with run-off from agricultural fields. Although workers differ in their opinions regarding the optimal recommended dose of ammonium sulphate for aquaculture (Lakshmanan et al 1971, Jhingran 1983, Sarkar 1991, on the Indian subcontinent the quantity of this fertilizer used in actual practice quite often surpasses the dosages recommended for aquacultural as well as for agricultural purposes, thus caus-'Addressee for correspondence.…”

Cellular responses in the skin of rainbow trout (Oncorhynchus mykiss) exposed to Rhine water

“…This was associated with the appearance of mitotic cells. Epidermal hyperplasia was also reported in the skin of fish exposed to water polluted with manure or lead (Iger et al, 1988;Iger, 1992), as well as in the branchial epithelium of fish exposed to low water pH or nitrogenous waste products such as ammonia (Lang et al, 1987;Wendelaar Bonga et al, 1990). It may represent a general and adaptive response of external epithelia to stressors.…”

“…However, most studies on the effects of pollutants on the body surface have been limited to the branchial or the intestinal epithelium (cf. Albassam et al, 1987;Lang et al, 1987; Burkhardt-Holm et al, revealed the formation of epidermal papillomas in fish exposed to polluted fresh water (Grizzle et al, 1984;Smith et al, 1989), the sensitivity of the skin to pollutants has received little attention. The skin of fish is a metabolically very active tissue, that quickly responds to stressors (Whitear, 1986;Iger et al, 1992), consisting of several cell types, in particular filament cells, mucous cells, sensory cells and chloride cells (Whitear, 1986).…”

Effect of Ammonia Concentration in Rearing Water on Growth and Blood Components of the Parrotfish Oplegnathus fasciatus

“…( Randall and Wright, 1987;Paust et al, 2011), , , , (Meade, 1985;Russo and Thurston, 1991) , (Lang et al, 1987), (McKenzie et al, 1993) (Ip et al, 2001). …”