Comparative Study On The Lipidomics Of Male Chinese Mitten Crab(Eriocheir Sinensis) During Reproductive System Development

Exp.1 Biochemical composition in the reproductive system of the mature male Chinese mitten crab,Eriocheir sinensisThe reproductive system of Chinese mitten crab,Eriocheir sinensis is complicated,and accessory gland,testis and vas deferens are three major constituents.However,no available information could be found on the biochemical composition of these three tissues for the mature male E.sinensis.Therefore,this study was conducted to investigate the proportion,proximate composition,fatty acid composition and amino acid contentsin the reproductive system of mature male E.sinensis.The results showed that:(1)the accessory gland index(AGI)was significantly higher compared to the testis index(TI)and vas deferens index(VDI)(P < 0.05).(2)For the biochemical composition,the contents of moisture,total lipid and total carbohydrate in the testis was significantly higher than the other parts(P < 0.05),while the highest crude protein content was detected for the accessory gland(P < 0.05).(3)For fatty acids profile,no significant differences were found for the percentages of the most saturated fatty acid(SFA),total saturated fatty acid(?SFA)and monounsaturated fatty acid(MUFA)among three parts,while the testis had the highest levels of C20:3n3,C20:4n6,C22:6n3,total polyunsaturated fatty acids(?PUFA),?n-6PUFA and total highly unsaturated fatty acids(?HUFA)(P < 0.05).(4)For amino acids composition,the highest contents of the major amino acids were detected for accessory gland,while the contents of L-lysine(Lys),valine(Val)and histidine(His)were shown as VD > AG > T(P < 0.05).In conclusion,the high contents of total lipid,total carbohydrate,PUFA and HUFA were stored in the testis of mature E.sinensis,while the accessory gland had the highest contents of crude protein and total amino acids.These differences may indicate their different physiological function for these tissues of mature E.sinensis.Exp.2 The lipidomic profiles on main tissues of male Chinese mitten crab,Eriocheir sinensisHepatopancreas,muscle and gonads are the main tissues of crabs,and the lipid profile is important for their gonad development and parental quality.This study was designed to determine and compare the fatty acids and lipidomic profiles for the main tissues of the mature male Eriocheir sinensis.The results showed as followings:(1)the highest total lipid content was detected in the hepatopancreas,while only 1% of wet weight total lipid is observed in muscle.(2)The percentages of C18:2n6,C20:4n6,C20:5n3 and C22:6n3 are the main PUFA in three tissues;the highest levels of C20:5n3 and C22:6n3 are detected in the muscle;the highest C20:4n6 level is detected in the gonads,while the highest C18:2n6 and the lowest C20:4n6,C20:5n3 and C22:6n3 levels are found in the hepatopancreas of male E.sinensis.(3)For the lipidomic profile,although there were a total of 11 classes of lipids(including LPE,LPC,PE,PC,PI,PS,TAG,DAG,SM,Cer,FA)identified in all tissues for males,the greater differences were found for the number of lipid moleculars in each lipid class.The hepatopancreas has the highest LPE,LPC,TAG,DAG and FFA contents,the highest PE content is found in muscle.(4)For the fatty acid chain,the longer and more unsaturated TAGs was found for males hepatopancreas,whereas the longer and more unsaturated fatty acid chain for DAG and PL were found in muscle.In conclusion,the greater difference in lipid molecules between the main tissues of the mature male E.sinensis,this may be related to the different functions of different tissues.Exp.3 Comparative study on the lipidomics of male Chinese mitten crab(Eriocheir sinensis)during reproductive system developmentThis study was to explore the lipidomics at different developmental stages of the male Chinese mitten crab,Eriocheir sinensis.(1)For the free fatty acid(FFA)composition,the highest levels of C18:3,C20:4,C20:5 and C22:6 are detected in the testis of the stage IV mature male E.sinensis,the highest levels of the most saturated fatty acids are present in the vas deferens.The highest levels of FFA detected in different developmental stages of testis are at the mature stage IV(P < 0.05).The highest content of the main saturated fatty acids and monounsaturated fatty acids was in stage II of accessory gland,while the highest content of C20:4 and C22:6 was at the mature stage IV(P < 0.05).(2)For the cholesterol ester(CE)composition,all of the CE levels in the mature stage IV testis was significantly higher than the other parts(P<0.05).Stage III testis has the highest content of CE 22:6,and the other CE highest levels are detected in stage IV(P < 0.05).During the accessory gland development,the highest levels of CE are detected in the stage IV(P < 0.05).(3)DAG,TAG,PC,PE,PG and PI are the main lipid in the stage IV reproductive system of male E.sinensis,the DAG,MAG,SM,PA,LPA,PC,PE,PG,PI and PS levels in testis are significantly higher compared to the accessory gland,vas deferens and spermatophore.With the development of the testis,the DAG,PE,and PG are significantly increase,and the contents of PS,TAG,PA,and PI are significantly decrease(P < 0.05).For the lipid composition of the accessory gland,most of the lipid content showed a downward trend with the development of accessory glands.For the number of carbon atoms and the number of double bonds in polar lipids and neutral lipid,with the development of testis,the contents of long-chain highly unsaturated DAGs are increases,while the most PA and PI contents are decreases.With the development of the accessory gonads,most of the PA,PC,PE,PG and PI showed a decreasing trend.In summary,the highest contents of long-chain highly unsaturated FFA,CE and most of the polar lipids and neutral lipids in the reproductive system of stage IV mature male crabs were detected in the testis(P < 0.05).The highest contents of main FFA,CE and polar lipids and neutral lipids were detected in the stage IV of testis,while the highest levels of these lipids in the accessory gland were detected in stage II.