Effect of cadmium on pekin duck total body water, water flux, renal filtration and salt gland function

The following hypotheses were examined using Pekin ducks (Anas platyrhyncho s) as a model for marine ducks: cadmium (Cd) intake affects iii salt gland and/or kidney function of ducks and (2) osmoregulation differently in male and female ducks. Birds were fed 0, 50, or 300 mu g Cd/g food. They were gr adually acclimated to 450 mM NaCl and then drank 300 mM NaCl for 3 mo while salt gland secretion (SGS), glomerular filtration rate (GFR), total body w ater (TBW), and water flux (WF) were measured in ducks eating control and h igh-Cd diets. Cadmium ingestion did not markedly affect body mass, but sign ificantly enlarged the salt glands and kidneys. Enhancement of kidney mass was greater in males. Cadmium ingestion did not affect TBW or WF, but tende d to increase interstitial fluid space at the expense of intracellular flui d. Sex did not affect TBW, but males had greater WF. Birds that ale Cd diet s, especially the higher Cd diet, exhibited renal tubular damage and lower GFR. Ducks that ate Cd had lower plasma sodium concentration and osmolality and, to activate SGS, required longer infusion of NaCl and larger incremen ts in extracellular osmolality and volume. Cadmium ingestion did not affect SCS rate or [Na+]. Both hypotheses were accepted since birds that are Cd h ad lower GFR and delayed onset of SGS in response to salt challenge and the effects of Cd oo the size and response of excretory organs were sexually d isparate. Cadmium appeared to compromise the salt excretion of Pekin ducks. However, they are less salt tolerant than seaducks and, in this study, had higher organ Cd concentrations than those seen in wild ducks. Further stud ies are needed to determine if these observations also apply to the more sa lt-tolerant seaducks.