Effects Of Vitamin E And Schizochytrium Sp.on Spermatophore Regeneration In Penaeus Monodon

Penaeus monodon is an important aquacultural species in China.The farming area spreads over the coastal areas of Guangdong,Fujian,Guangxi,Zhejiang and other provinces in China.It is favored by consumers because of its large individual,delicious meat,and high nutritional value.However,the male broodstock often has a low rate of sperm production and a low rate of spermotophore utilization,during the artificial breeding process,which resulting in the low spawning rate and the low hatching rate of female shrimp.These problems will affect the survival rate of the offspring.It is difficult to improve the efficiency of hatchery populations of P.monodon.Nutrition is an important determinant of gonad maturation and seedling quality for shrimp.Natural food such as cocoon,oyster,squid,squid and so on has a promoting effect on gonad development and reproduction of broodstock,and its essence is closely related to its specific nutritional composition.That,how to improve the rate of sperm production and spermatophore utilization,is an urgent problem to be solved in the current production applications and industrial development.In this paper,the effects of different nutrient baits were used on male prawns of P.monodon,and explored the development and regeneration patterns of male prawns from P.monodon from the aspects of nutrition and feed,histology and tissue expression analysis.The artificial breeding provides a theoretical reference.The experimental results are as follows:1.Effects of Different Levels of Vitamin E(VE)on the Spermatophore Quality of the Male P.monodonIn this study,four different contents of vitamin E(0,200,600,and 1000 mg·kg-1)in the basal diet were treated,to feed mature male P.monodon which were extruded spermatophore for 40 days.The weight of regenerated spermatozoa of males in each experimental group supplemented with vitamin E was significantly higher than the initial value of the experiment,whereas there was no significant difference in the weight of the tertiary spermatophore of males in the control group.The weight of spermatophore regenerated for the first time in each group was greater than that of the control group.The weight of spermatophore in the E1000 group was significantly greater than that in the control group(P < 0.05).The difference between the E200 group and the E600 group was not significant.In the experiment,the weight of the second regenerated carp was higher than that of the control group.The weight of the carcass of the E600 group was significantly higher than that of the control group(P <0.01),and was significantly greater than that of the E200 group and the E1000 group(P <0.05).There was no significant difference between the E200 group and the E1000 group.After the first spermatophore regeneration,the sperm count in the E200 group was significantly higher than that in the control group and the E1000 group(P <0.01),which was significantly higher than that in the E600 group(P <0.05),while the sperm population in the control group and the E1000 group were not significant difference(P>0.05).After the second spermatophore,the total number of spermatozoa in the three experimental groups was higher than that in the control group.The total number of spermatozoa in the E200 group was significantly higher than that in the control group(P < 0.01).The three indicators comprehensive sperm weight,sperm quantity,and living sperm percentage,showed that addition of 200 mg/kg of vitamin E to the feed could effectively promote spermatophore regeneration and improve sperm quantity in male P.monodon.2.Effects of Vitamin E and Schizochytrium sp.(Sch)on the Re-development of Spermatophore,Sperm Count and Vigor of P.monodonIn this study,we treated four different contents of vitamin E and Schizochytrium sp.in the basal diet(Control group;VE200;1% Sch;VE200+1% Sch),to feed mature male P.monodon which were extruded spermatophore for 40 days.The results show: The percentage of viable spermatozoa in group B was significantly higher than that in group A(P<0.05).The difference was not significant that the number of viable spermatozoa in group C was comparable to group A(P>0.05).The total number of spermatozoa in group D was significantly higher than that of group A(P<0.05).The three indicators of comprehensive(sperm quality,sperm count,and percentage of viable spermatozoa)show that the addition of 1% Schizochytrium sp.and 200 mg·kg-1 of vitamins in feed has a synergistic effect on the regeneration of spermatophore and the increase of sperm count in P.monodon.3.Effects of Vitamin E and Schizochytrium sp.on Microstructure and Submicroscopic Structure of the Spermatophore of P.monodonIn this study,we treated four different contents of vitamin E and Schizochytrium sp.in the basal diet(Control group;VE200;1% Sch;VE200+1% Sch),to feed mature male P.monodon which were extruded spermatophore for 40 days.The results show: After the addition of vitamin E and Schizochytrium sp.in feed,the number of spermatium in spermatophore increased significantly,reaching a significant level among the groups(P<0.05).The combination of vitamin E and Schizochytrium sp.significantly increased the number of spermatium compared to vitamin E alone or Schizochytrium sp.alone(P<0.05).4.Effects of Vitamin E and Schizochytrium sp.on Gene Expression in the MAPK/Erk(mitogen-activated protein kinase / extracellular signal-regulated kinase)Signaling Pathway in Male Spermatogonial Development of P.monodonIn this study,we treated four different contents of vitamin E and Schizochytrium sp.in the basal diet(Control group;VE200;1% Sch;VE200+1% Sch),to feed mature male P.monodon which were extruded spermatophore for 40 days.The results show: Ras gene expression in group D was higher than other groups in the MAPK/Erk signaling pathway,which was significantly higher than group B(P <0.05);PKC gene expression in group D was significantly higher than other groups(P<0.05);The expression of MP1 gene in group C was significantly higher than that in other groups(P<0.05);the expression levels of Mos and MNK2 in group C and D were significantly higher than those in group A and B(P<0.05).The expression of MEK1 gene in group D was higher than that in other groups,which was significantly higher than that in group A and C(P<0.05);the expression level of Erk gene in group A and D was significantly higher than that in group B and C;the expression of CREB gene in each group was not significantly different(P>0.05).The expression of c-Myc gene in group D was significantly higher than that in other groups(P<0.01),and the expression of group D was 18.54 times that of group A,which was 4.46 times that of group B and 14.11 times that of group C.Each gene on the MAPK/Erk signaling pathway participates in the spermatophore regeneration of P.monodon.Vitamin E and Schizochytrium sp.may contain some growth-promoting factors,which activate nuclear transcription factors through signal transduction.These growth-promoting factors may promote cell proliferation and differentiation,and promot spermaphore maturation finally.Comprehensive evaluation of quality and number of spermatozoa,histology and electron microscopy of regenerated spermatophore,and expression of related genes in the MAPK/Erk signaling pathway results: there is a synergistic effect in the regeneration of the spermatophore with the addition of 1% Schizochytrium sp.and 200 mg·kg-1 vitamins to the diet.The experimental results provide scientific basis for the multiple use of male shrimps in the breeding of P.monodon.