Effects Of V_C And V_E On Respiration Metabolism And Antioxidant Enzymes Of Macrobrachium Nipponense In The Molt Cycle

The molt cycle of the freshwater prawn Macrobrachium nipponense is firstly divided into six stages, that is early postmolt(A), late postmolt(B), intermolt(C), early premolt(D1), late premolt(D2', D2"), molt(E), with the development of plepod setae and hardness of exoskeleton. During the study, we firstly discover that every internal cone locates 1/4-1/5 of setal lumen, which is different with that of seawater shrimps; new setae extend into the old setal lumens and end the old setal internal cones.It is Investigated that the effects of vitamin C and E on M. nipponense in different molting stages by measuring oxygen consumption rates, ammonia-N excretion rates and activities of antioxidant enzymes(SOD,CAT,GSH-Px,GST,GR) in three groups which are control group,Vc group and (Vc +VE )group.1. The oxygen consumption rates are high in stages D2 and A, but low in stage C. The ammonia-N excretion rates decrease from stage A to stage D2 and the O:N values increase from stage Ato stage D2. It is indicated that the metabolism of M nipponense is strong before and after molt and steady in intermolt. To be compared with control group, the effect of dietary supplemented vitamin C and E on metabolism and growth is better than that of supplemented vitamin C.2. It is investigated that high ?O2~ values and low activities of antioxidant enzymes in stage A; decreasing ?O2~ value and increasing activities of antioxidant enzymes in stage B; balance period of the production of reactive oxygen and the elimination of reactive oxygen in stage C; increasing ?O2" value and low activities of SOD and CAT, but higher activities of GST and GR in stage D.The result is that the ?O2~ values decrease and the activities of SOD and GSH-Px remarkably increase in the molt cycle, the activities of CAT remarkably increase in postmolt and intermolt, and the activities of GR and GST remarkably increase inintermolt while the dietary is supplemented Vc. To be compared with Vc group, the ?O2~values are higher before and after molt and lower in intermolt, the activities of SOD and GSH-Px remarkably increase, the activities of CAT are steady, the activities of GST decrease, the activities of GR are higher in stages B and D2 in (Vc +VE) group. Therefore, Vc and VEcan not only eliminate reactive oxygen but also save or induce the increasing of the antioxidant enzymes. In a word, the effect of Vc and VE on enhancing the antioxidant activity is better.