PARENT SESSION
IP07 - Fate & Effect of Metals: Aquatic Dietary Perspectives
Chair: Fisher, Nick¹, ¹ Stony Brook University, Stony Brook, NY
2:10 PM to 5:30 PM - Monday, 18 November 2002
Room Room 150 G

(IP56) Effect of Calcium in the Diet on Cadmium and Calcium Uptake Kinetics.

Baldisserotto, B^*,1, Kamunde, C², Matsuyo, AYO³, Wood, C², ¹ UFSM, Santa Maria, RS, Brazil² McMaster University, Hamilton, ON, Canada³ INPA, Manaus, RS, Brazil

ABSTRACT- This study investigated the interactions between dietary calcium (Ca) and acute waterborne cadmium (Cd) exposure on waterborne Ca and Cd uptake across the gills in rainbow trout (Oncorhyncus mykiss) juveniles. Fish were fed with four treatment diets (g Ca/g food): 20 (control), 30 and 60 (with CaCl₂), and 30 and 60 (with CaCO₃). After 7 days fish were placed for 3 h in chambers containing 10 Ci/L ⁴⁵Ca or 2 Ci/L ¹⁰⁹Cd and 50 g/L Cd in moderately hard water. Controls for each diet treatment were submitted to the same treatment but without the addition of Cd to the water. Mortality was higher in fish fed with 60 mg/g CaCl₂ than controls. Acute exposure to waterborne Cd reduced waterborne Ca uptake in all treatments. Higher Ca diets (except 30 mg/g CaCO₃) reduced waterborne whole body Ca uptake and newly accumulated Ca in the carcass and plasma, but not in gills, liver, and red blood cells, and did not change total Ca levels in the studied organs and plasma in relation to control. Whole body Cd uptake and newly accumulated Cd in the gills, kidney, liver, and plasma were lower in fish fed with Ca-supplemented diets than controls. Therefore, we conclude that the addition of Ca in the diet reduced the branchial uptake of both Ca and Cd in rainbow trout. Supported by MITE-RN, CAPES-Brazil, and CNPq-Brazil.

Key words: dietary calcium, aqueous cadmium uptake, fish