Effects Of Dietary Nano-se On The Growth Performance And Oxidation Resistance For Eriocheir Sinensis

Selenium(Se), as an essential trace element for human and animal growth, can strength immune function of aquatic animal and improve the resisting infection ability of pathogenic bacteria. In this paper, Eriocheir s inensis was chosen as experimental object to study the effect of dietary selenium on growth performance,quality,selenium content in edible parts,disease resistance and antioxidant capacity in order to determine dietary selenium requirements for Eriocheir sinensis.Crabs(mean weight: 4.5±0.2 g) were divided seven groups randomly. Nano-se as additives was added to the basal diet at six levers: 0, 0.1, 0.2, 0.4, 0.8, 1.6 mg/kg, and1.0 mg/kg yeast selenium additive was as a positive control group simultaneously.After 90 days, detected the growth performance indices; Se contents in hepatopancreas and muscle; hypoxia tolerance, hemocyanin content, total haemocyte count(THC), the content of lactic acid(LD) of each tissue and antioxidant capacity after hypoxia stress.The main results were summarized as follows:1. Effects of dietary Nano-se on growth,nutritional composition and selenium content of Eriocheir sinensisThe feeding trail results turned out that, the dietary Nano-se has significant effect on specific growth rate(SGR) and survival rate(SR) while has no significant effect on feed coefficient(FC) and condition factor(CF). SGR of 0.2 mg/kg dose group was higher than other Nano-se groups(p<0.05) except 1.0 mg/kg selenium yeast. SR of 0.2mg/kg group was not significantly higher than other groups(p>0.05) except 1.6 mg/kg group(p<0.05).Nano-se has significant effect on crude protein(CP) and the impact of 0.2 mg/kg group was most outstangding of all the Nano-se groups(p<0.05). Essential amino acid of groups which added with Se were higher than 0 mg/kg group(p<0.05). The content of testy amino acids of 0.2 mg/kg group was significantly higher than 0 and 0.1 mg/kggroups(p<0.05). The crude content of the dietary groups which added with se were higher than 0 mg/kg groups. unsaturated fatty acid got the highest values in 0.2 mg/kg groups(p<0.05).Dietary Nano-se has significant effect on the se content of hepatopancreas, Se content in the groups which added se were higher than the blank group(p<0.05), se content of hepatopancreas showed a rising trend at the dietary Nano-se from 0.1 mg/kg to 0.8 mg/kg, when dietary Nano-se up to 1.6 mg/kg,it would be no longer rising. There was no significant effect on the se content of muscle.2. Inoculation A.hydrophila to verificate the protective effect of dietary Nano-se on Eriocheir sinensis under hypoxia stressDietary Nano-se has significant effect on the immune protection rate of Eriocheir sinensis after injection of A.hydrophila under hypoxia stress. The immune protection rate of Eriocheir sinensis increased first and then decreased with the increase of dietary Nano-se, and 0.2 mg/kg dose group was significantly higher than other groups(p<0.05)except 1.0 mg/kg selenium yeast. After hypoxia stress 24 hours, 0.2 mg/kg dose group of Eriocheir sinensis,the highest survival rate(p<0.05).3. Effects of dietary Nano-se on hypoxia tolerance, hemocyanin content, THC and LD of Eriocheir sinensisDietary Nano-se has significant influence on hemocyanin content and THC of Eriocheir sinensis, after hypoxia stress 12 hours,0.2 mg/kg group was significantly higher than other groups(p<0.05); Hemocyanin content and THC of Eriocheir sinensis of Each group were all declined after hypoxia stress 24 hours, and there was no difference between groups 0.2 and 0.4 mg/kg on THC. LD in each group increased with the extension of hypoxia stress,but there is no significant difference between groups(p>0.05).4. Effects of dietary Nano-se on the antioxidant ability of Eriocheir sinensis under hypoxia stressNano-se dietary has significant effect on the activity of antioxidant enzyme(GSH-Px、T-AOC、SOD and CAT) and the content of GSH, MDA. Before hypoxia stress,with the increasing of dietary Nano-se,the activity of enzyme and the content of GSH increased first and then decreased and the maximum was appeared at0.2 mg/kg group(p<0.05),but the content of MDA showed opposite, and the lowest in0.2 mg/kg group(p<0.05).When hypoxia stress 24 hours, the activity of GSH-Px, SOD and CAT of 0.2 mg/kg group was higher than the groups of 0,0.8,1.6 mg/kg(p<0.05),while there was no difference in muscle and gill(p>0.05). No difference existed between 0.2 and 0.4 mg/kg on the ability of T-AOC(p>0.05),but 0.2 mg/kg group was higher than other groups(p<0.05);the content of GSH was significantly decreased after hypoxia stress 24 hours, and 0.2 mg/kg was higher than other groups(p<0.05),at the same time, the content of MDA was lowest at the group of 0.2 mg/kg(p<0.05).All these results demonstrated that added Nano-se 0.2 mg/kg can promote the growth performance, nutritional composition, added Nano-se between 0.2 mg/kg and0.4 mg/kg can promote the capacity of hypoxia tolerance and antioxidation of Eriocheir sinensis. We suggest that added 0.2 mg/kg Nano-se to the feed of Eriocheir sinensis.