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INTRARUMINAL AND SYSTEMIC RESPONSES TO VARIATIONS IN INTAKE OF SODIUM AND POTASSIUM BY SHEEP
Author(s) -
Warner A. C. I.,
Stacy B. D.
Publication year - 1972
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1972.sp002158
Subject(s) - potassium , sodium , rumen , zoology , chemistry , electrolyte , urine , excretion , medicine , endocrinology , food science , biochemistry , biology , fermentation , organic chemistry , electrode
A maintenance diet providing about 200 m‐equiv potassium and 30 m‐equiv sodium per day was given to sheep; on this intake sodium and potassium balances were small and positive. When potassium chloride was added to the diet to provide a total of about 700 m‐equiv potassium per day, the potassium content of the rumen increased and the sodium content decreased, apparently due to an increased rate of absorption of sodium across the rumen wall. The rate of excretion of sodium in the urine was increased for about 4 days, giving a considerable negative sodium balance; the extra amount excreted was of the same order of magnitude as the loss from the rumen. Water consumption increased by 0·5–0·9 l./day, without change in water balance. The apparent potassium balance increased by an amount much greater than could be accounted for by changes in rumen content. When the potassium content of the diet was returned to its initial value there was an intense retention of sodium by the kidney, with signs of increased adrenocortical activity and a strongly positive sodium balance for about 14 days. During this time the sodium content of the rumen increased and the potassium content decreased slowly to about initial values. Water consumption retumed to normal and the potassium balance dropped, often to low or even negative values for a while. The mechanisms apparently permitting the rumen to dominate the response of the whole animal to changes in the electrolyte content of the diet are discussed.