L-ASCORBYL-2-SULFATE ALLEVIATES ATLANTIC SALMON SCURVY

Duplicate lots of 150 Atlantic salmon (Salmo salar), average weight 0. 5 g, were fed NRC diet H-440 base containing L-ascorbic acid (C-1) or L-ascorbyl-2-sulfate (C2S); or L-ascorbyl-2-monophosphate (C2MP): at 0 or 100 mg C-1; 50, 100, 300 mg C2S; or 50, 100 mg C2MP per kg dry die t in 12 degrees C freshwater tanks. After 12 weeks, negative controls (no vitamin C) exhibited reduced growth, scoliosis, lordosis, and pete chial hemorrhages typical of fish scurvy. All other lots grew normally . Four 100-fish lots of scorbutic salmon, average weight 3.3 g, were p laced on recovery diets of 0, 50, or 300 mg C2S, or 100 mg C2MP per kg dry diet. After 5 weeks, fish fed either level of C2S intake had reco vered and resumed growth. Negative controls continued to develop acute scurvy. The 41 survivors in this no-vitamin-C group all had advanced scurvy, whereas all fish in both CPS-fed recovery groups appeared norm al. Tissue assays for C vitamers disclosed normal levels of C-1 and C2 S in the recovery groups. All other test treatment lots containing C-1 , C2S, or C2MP had fish with normal appearance and no significant diff erences in growth response for the 17-week test period. C2S at 50 mg o r more per kg diet as the sole vitamin C source promoted normal growth in young Atlantic salmon for more than 20-fold increase in weight.