Effect of Different Dietary Levels of Salt-mixtures on Growth and Body Composition in Carp

Abstract

A 56-day feed trial was conducted to examine the effect of feeding graded levels of a saltmixture (0-6%), as compared with an established mineral supplement (4%, McCOLLUM'S saltmixture no. 185 plus trace elements), on the growth and body composition of carp.
Fish fed the ration containing 4% McCOLLUM'S salt-mixture plus trace elements displayed the highest overall growth response and feed efficiency over the experimental test period. For those fish fed graded levels of the salt-mixtures, maximum growth was obtained at the 2% incilusion level.
In contrast to fish fed mineral supplemented rations, fish fed a ration containing no mineral supplement displayed reduced growth, low feed effciency, loss of muscle tone, decreased heamatocrit, decreased haemoglolbin and serum glucose concentration, elevated carcass moisture, Ca, P and Na content, and reduced carcass protein, lipid Mg, Fe, Zn and Cu content.
The data present indicates the necessity of a dietary mineral supplement for carp fed a purified ration based on casein, potato starch, dextrin and lipid.