Potassium and Sodium Balances During Dietary Potassium Restriction in Sheep

Abstract

The inputs and outputs of potassium (K) and sodium (Na) were measured in six lambs prior to and during a 4-day period of acute dietary K restriction. During the predepletion period, urinary K accounted for 60.4% of the total K excreted. Renal K and Na excretion decreased during the initial stage of K restriction. Renal K excretion then continued to decrease and reached a minimum level after 40 h of K restriction, whereas fecal K excretion decreased only moderately from predepletion levels. A transient natriuresis, which occurred concurrently with the minimum level of urinary K, supported the hypothesis of the existence of a renal peritubular Na–K exchange mechanism. The delay in renal K conservation mechanisms, together with an obligatory fecal K excretion, caused an acute K deficit, estimated at 6.7–11.4%, in lambs fed a low K diet (0.032% K) for 4 days.

Potassium

“…The clinical requirement of finishing lambs is 3.4 g K kg À1 feed DM, and their normative requirement is 5.5 g kg À1 feed DM. Sheep and lambs fed low-potassium diets (< 3 and < 1 g kg À1 DM, respectively) exhibited a marked decrease in feed intake, loss of weight, lack of alertness, stiffness extending from the hind legs to the forelegs, hypoglycemia and histological changes (Brink 1961, Telle et al 1964, Cowan and Phillips 1973, McDowell 1992.…”