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Studies on the north sea cod VI.—Effects of starvation 4. Sodium and potassium
Author(s) -
Love R. M.,
Robertson I.,
Strachan I.
Publication year - 1968
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740190715
Subject(s) - potassium , extracellular , sodium , flesh , zoology , chemistry , connective tissue , fish <actinopterygii> , starvation , extracellular fluid , biophysics , biology , medicine , anatomy , food science , endocrinology , biochemistry , fishery , genetics , organic chemistry
Sodium and potassium were measured in captured cod of a variety of degrees of starvation, and in cod artificially starved in an aquarium. It was found that depletion of either kind caused the ash of both muscle and blood to decrease, while the water increased. In muscle, Na increased and K decreased, but both ions decreased in the blood plasma. It was demonstrated histologically that conditions producing more Na and less K gave rise to an increase in extracellular space and shrinkage of the muscle cells. Myocommata (sheets of connective tissue) were found to be rich in Na. As the myocommata are more concentrated in the tail region, this alone was thought sufficient to explain the high Na concentration in the flesh at the tail ends of many fishes compared with the middle. A clear relationship was demonstrated between the size of the fish and the Na content of the musculature. This decreased with growth, a fact which was thought to be the result of larger fish having larger cells, and therefore less extracellular space which is rich in this ion. It was found that there was no relationship if the fish were depleted in the spawning season. There was in addition an unknown factor whereby both Na and K showed an overall shift from month to month.