Effects of Dietary Sodium Chloride on Red Drum Juveniles in Waters of Various Salinities

Abstract

Abstract Three 8-week feeding trials were conducted to determine the effects of supplemental dietary salts on growth and osmoregulation of juvenile red drums (Sciaenops ocellatus) at various water salinities. In each experiment, sodium chloride was added to a basal diet composed of semipurified and practical ingredients; the basal diet provided intrinsic levels of 0.80% Cl, 0.84% K, and 0.92% Na on a dry-matter basis. In fresh water, red drums fed the basal diet supplemented with NaCI at 2% had significantly (P < 0.05) greater weight gain and feed efficiency than fish given the basal diet alone. In brackish water (6‰ salinity), fish given the diet supplemented with NaCI at 2% had weight gains that were numerically but not significantly (P = 0.076) greater than gains offish fed the basal diet. In full-strength artificial seawater (35‰), fish fed diets supplemented with NaCI at 2 and 10% had weight gains not significantly (P = 0.23) different from those of fish fed the basal diet, and those fed the diet sup...