EFFECTS OF DIETARY ZINC ON DEVELOPMENT OF REPRODUCTIVE SYSTEM OF MALE CHINESE MITTEN 2HANDED CRAB (ERIOCHEIR SINENSIS)

This study investigated the effects of dietary zinc on the development of reproductive system in male Chinese mitten2handed crab (Eriocheir sinensis). Zn sulfate (ZnSO4) was added as dietary zinc source. The crabs were assigned to five groupsand fed with an artificial compound diet which added different content of zinc except controls, group 1 to group 4 were added50mg/kgfeed, 100mg/kgfeed, 200mg/kgfeedand 400mg/kgfeedof zinc, respectively. The experiment lasted for 70 days and theresults were as follows: zinc content of testis and glandula accessoria of group 2 was the highest (300mg/kg and 150mg/kg, re2spectively) of all the groups. Controls was zinc non2added, but its zinc content of testis and glandula accessoria were still reachedto 85mg/kg and 67mg/kg, respectively. The testosterone concentration and GSI (G onadosamic index) of group 2 were also thehighest one (0.835ng/mL and 25194×10-3, respectively), and controls was the lowest one. In testis, the activities of AKPandLDH increased fastly and then descended rapidly during the whole experiment, and all groups reached their peaks at 30days, and group 2 was always the highest one between all groups. In glandula accessoria, the activitiesof AKP andLDH reachedtheir peaks at 50 and 70 days respectively, and group 2 was still the highest one, and it was important to mention, the activityof AKP descended quickly after its peak, and reached very lowlevel at the endof the experiment. All results suggested: the content of zinc in reproductive system based on the proper content of dietary zinc, and once zinc over2added it would resulted in thereduce of the zinc accumulation; Proper zinc content could accelerate the speed of development of reproductive system and increase the secretion of testosterone ; The activities of AKP and LDHof testis and glandula accessoria had obvious relevancy withits zinc content.