Influence of dietary ascorbate derivatives on tissue copper, iron and zinc concentrations in grass shrimp, Penaeus monodon

Abstract

Effects of three ascorbate derivatives namely, l-ascorbyl-2-sulfate (C2S), l-ascorbyl-2-monophosphate–Mg (C2MP–Mg) and l-ascorbyl-2-polyphosphate (C2PP) on tissue (hepatopancreas and muscle) copper, iron and zinc concentration in juvenile grass shrimp, Penaeus monodon, were studied. The control diet contained 12 mg/kg copper, 318.1 mg/kg iron, 125.8 mg/kg zinc and 0 mg/kg ascorbate supplemented with either adequate or high (5× adequate) dietary levels of C2S, C2MP–Mg and C2PP. Each diet was fed to triplicate groups of shrimp (mean initial weight: 0.67±0.05 g) for 8 weeks. Significantly ( P<0.05) higher tissue iron and lower copper concentrations were observed in shrimp fed diets containing ascorbate and high ascorbate, respectively, than shrimp fed the control diet regardless of the ascorbate source. Shrimp fed C2MP–Mg- and C2PP-containing diets had higher tissue iron concentrations than shrimp fed C2S-containing diets regardless of ascorbate supplementation level. Lower hepatopancreas copper concentrations were observed in shrimp fed C2MP–Mg- and C2PP-containing diets than in shrimp fed C2S-containing diets at the high ascorbate supplementation level. Tissue zinc concentrations in shrimp were not affected by either ascorbate source or ascorbate supplementation level.