Effects of dietary vitamins C and E and their interactions on reproductive performance, larval quality and tissue vitamin contents in kuruma shrimp, Marsupenaeus japonicus Bate

A 3 x 3 factorial feeding trial was conducted to investigate effects and interactions of vitamins C (VC) and E (VE) on reproductive performance, larval quality and body vitamin concentrations in kuruma shrimp. Pond-reared females (50 g mean body weight) were fed 9 experimental diets containing 3 grade levels of VC (0, 500 and 1000 mg ascorbic acid equivalent kg(-1) diet) and VE (0, 300 and 600 mg alpha-tocopherol kg(-1) diet) for 2 months. When ovaries reached stage IV, females were unilaterally ablated to induce spawning in a separated 1201 spawning tank under flow-through water system. The average temperature of water during the course of the experiment was 23.3 +/- 1.9 degrees C, dissolved oxygen 8.7 +/- 0.9 mgl(-1), pH 8.2 +/- 0.2, and salinity 31.6 +/- 0.7 gl(-1), respectively. Neither dietary VC nor VE was a significant factor on fecundity, but the hatching rates and metamorphosis rates of nauplii into zoea I significantly increased with increased either dietary VC or VE. On the other hand, there were significant interactions between two vitamins on those parameters. VE concentrations in hepatopancreas, ovaries, muscles and eggs significantly increased with increased dietary VE while those also increased with dietary VC concentrations, particularly in 1000 VC fed groups, the values were significantly higher than those of others in most cases regardless of dietary VE concentrations. VC concentrations in hepatopancreas, ovaries, muscles and eggs significantly increased with increased dietary VC, but effects of dietary VE on VC concentrations in those organs were varied. In other words, the regeneration effect of VC on VE concentrations and the sparing effect of VE on VC concentrations in the organs of female shrimp were demonstrated in this study. Supplementations of VC and VE in maturation feeds for female shrimp are recommended to obtain higher egg hatchability and better quality larvae. (C) 2012 Elsevier B.V. All rights reserved.