The effects of dietary Zinc on growth, immunity and reproductive performance of female Macrobrachium nipponense prawn

摘要

We accessed the effects of dietary Zn on growth, immunity and reproductive performance in female Macrobrachium nipponense. After feeding with a homemade diet containing 21, 50, 81, 136 and 203 mg kg(-1) Zn for 60 days, prawns showed a significant increase in weight gain, improved survival, higher hepatosomatic and gonadosomatic indices (p < 0.05) in group 50 and 81 mg kg(-1) Zn. Broken-line analysis indicated that the optimal concentration of dietary zinc was 75.48 mg kg(-1). Dietary Zn had drastically increased crude lipid content in body composition (p < 0.05), while moisture, ash and crude protein had no significant difference among groups (p > 0.05). Zn content in hepatopancreas linearly increased along with increases in dietary Zn, while Zn content in muscle and haemolymph had no difference in Zn supplemented groups (p > 0.05). The highest activities of Cu/Zn-SOD, T-SOD and CAT in hepatopancreas were in 81 mg kg(-1) and 50 mg kg(-1) Zn diet, respectively. MDA had the lowest content in 21 to 81 mg kg(-1) Zn levels. The highest haemolymph AKP activity was in 81 mg kg(-1) Zn diet group, while the highest PO activity was in 136 mg kg(-1) Zn diet. Both levels of progesterone and estradiol and gene expression of VG and VGR were highest in 50 to 81 mg kg(-1) Zn levels. These results provided evidence that dietary Zn ranging from 50 to 81 mg kg(-1) has a positive impact on growth, immunity and reproductive performance of female prawn.