Effect of waterborne and dietary cadmium on plasma ions of the teleostOreochromis mossambicus in relation to water calcium levels

Abstract

Please be advised that this information was generated on 2018-05-08 and may be subject to change.Arch. Environ. Contam. Toxicol. 18, 568-575 (1989) Abstract. The effects of cadmium administered via ambient water or food on plasma ions of the Af rican freshwater cichlid Oreochromis mossambicus were studied for 2, 4, 14, and 35 days, in low cal cium (0.2 mM) and high calcium (0.8 mM) water. In low calcium water, an environmentally relevant concentration of 10 fig/L water-borne cadmium in duced a significant and dramatic hypocalcemia on days 2 and 4. Recovery of plasma calcium was ob served on days 14 and 35. Hypermagnesemia was observed on day 2, but normal levels were already found on day 4. In high calcium water adapted fish, the extent of hypocalcemia and hypermagnesemia was less pronounced than in fish from low calcium water. Water-borne cadmium caused no significant changes in plasma phosphate, sodium, potassium, or osmolality. On days 2 and 4, dietary cadmium (averaging 10 fxg Cd/fish/day) caused hypermagne semia and hypocalcemia in low calcium wateradapted fish. Recovery was observed on days 4 and 14, respectively. In fish from high calcium water, dietary cadmium caused a significant reduction in plasma calcium on day 4 only; plasma magnesium was unaffected. Hyperphosphatemia was apparent on day 14, irrespective of the water calcium con centration. No changes in plasma sodium, potas sium, or osmolality were found.^V r c h i v e a oThe results show that sublethal concentrations of cadmium, administered via the water as well as via the food, affect calcium and magnesium metabo lism in tilapia. High water calcium ameliorates the

Effects of water-borne cadmium on plasma cortisol and glucose in the cichlid fish Oreochromis mossambicus

“…The restoration of plasma cortisol and glucose levels observed in the present study, and the recovery of plasma calcium and magnesium levels reported earlier (Pratap et al, 1989) suggest that tilapia develop tolerance to sublethal concentrations of ambient cadmium on prolonged exposure. Recovery of plasma electrolyte levels has been observed in rainbow trout exposed to cadmium (Giles, 1984) and copper (Lauren and McDonald, 1987).…”

“…It seems there fore possible that the increase of plasma cortisol by cadmium, observed in this study, is mediated by cadmium-induced changes in plasma electrolytes. However, at the same cadmium concentration as used in this study, we only found severe reduction of plasma calcium and increase of plasma magnesium, whereas plasma sodium and potassiu/n levels and plasma osmolality were not significantly affected (Pratap et al, 1989;Fu et al, 1989). The rise in corti sol is therefore unlikely to be mediated by a decline in plasma sodium, potassium or osmolality.…”

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

“…Elevation of the calcium content in the ambient water enhanced the recovery. In a comparable experiment we have shown earlier that high water calcium levels reduce the plasma electrolyte losses in tilapia exposed to cadmium (Pratap et al, 1989). The protective action of high water calcium levels and water hardness against toxic metals has been reported by several authors (e.g., Pascoe et al, 1986;Wicklund and Runn, 1988).…”

“…The fish were subsequently exposed to either 10 jug Cd/1 of ambient water or were fed cadmium-containing food averaging 10 //g Cd/fish/day. Fish mainte nance, preparation of cadmium food and administration of ambient or dietary cadmi um were reported earlier (Pratap et al, 1989). The experimental set-up is shown in Table 1.…”

Untitled

“…Previous studies have shown that Pb 2+ causes disruption of Na + , Cl -and Ca 2+ regulation and disruption in hemoglobin synthesis (Hodson et al, 1978;Rogers et al, 2003Rogers et al, , 2005Rogers and Wood, 2004 , by which this metal directly competes with Ca 2+ for uptake at calcium binding sites and can enter the cells through similar transport pathways (Verbost et al, 1987(Verbost et al, , 1989Spry and Wood, 1985;Rainbow and Blackmore, 2001). Similarly, waterborne Ca 2+ has a marked protective effect against waterborne Cd 2+ toxicity to brook trout (Carrol et al, 1979), tilapia (Pratap et al, 1989;Pratap and Wendelaar Bonga, 1993) and rainbow trout (Hollis et al, 2000;Hansen et al, 2002;Baldisserotto et al, 2005). Our previous study showed that there were exposure dependent decreases in the branchial Na + /K + -ATPase activity in the tissues of Tilapia zillii exposed to Cu 2+ and Pb 2+ (Ay et al, 1999).…”