EFFECTS OF SUPPLEMENTAL DIETARY-SODIUM CHLORIDE AND RESTRICTED DRINKING-WATER ON MINK

Thirty-six male mink were fed diets that contained 0, 1, 2 or 4% suppl emental salt (sodium chloride) and were given drinking water ad libitu m for 7 d. Three mink on each diet were then placed on ad libitum, 50% ad libitum or 25% ad libitum drinking water for the next 14 d. Ad lib itum water consumption was directly proportional to the salt content o f the diets. Feed consumption was inversely related to the level of di etary salt, although water restriction had a greater effect in reducin g feed consumption than did the supplemental salt. The clinical signs of salt toxicity-water restriction observed were increased thirst, mil d dehydration, decreased feed consumption, decreased body weight, roug h coat, crusty nose and eyes, irritability In the early stage, and let hargy In the later stages. In general, serum and urinary sodium and ch loride ion concentrations increased with increasing dietary salt conce ntrations. Expressed as a percent of brain weight, liver, spleen, kidn ey and heart weights of mink fed supplemental salt were less than the control weights. Adrenal gland weights increased in response to water restriction. Brain sodium concentrations were not affected by salt sup plementation when drinking water was provided ad libitum. However, res tricting drinking water generally resulted in increased brain sodium c oncentrations. Mild to moderate micro- or macrovesicular vacuolar chan ges were observed in the livers of some mink fed each level of dietary salt, but were especially prominent in the mink restricted in drinkin g water.