Salt appetite during pregnancy in sheep

Abstract

Sodium preference was examined in three groups of sheep which had all sustained two consecutive pregnancies and lactations on either adequate sodium intakes (group C) or low sodium diets (B and C). Group B received a potassium supplement as well as a low sodium diet during the present experiment. No convincing or sustained increase in sodium preference resulted from the reduction in body sodium caused by pregnancy and lactation in group B or C, whether the sodium solutions offered were 40 or 300 mmol/l. In a second experiment, sodium preference (sodium bicarbonate, 40 mmol/l) was studied throughout pregnancy in sheep on low or adequate sodium diets, also non-pregnant controls on low sodium diets. Again, pregnancy on a low sodium intake failed to intensify salt appetite except for a transient (but significant) peak around d90, close to the peak of aldosterone secretion; a similar increase in preference occurred on the adequate sodium diet. However, salt appetite failed to intensify during the period of peak sodium demand (the last third of pregnancy) whereas renal and faecal sodium conservation are appropriately increased.