| The changes of morphology,protein composition,and fatty acid composition of silkworm pupae at four storage stages were analyzed,and the antioxidant activity of silkworm pupa oil in vitro was analyzed.The mechanism of antioxidation and lipid-lowering of reeling pupa oil in vivo were also discussed.In order to provide a theoretical basis for improving the added value of silk reeling pupa,a by-product of silkworm processing.The main research conclusion received through the experiment is as follows:（1）The morphology,protein composition,fatty acid composition,and activity of silkworm pupa were affected by cocoon storage time.The results showed that with the extension of storage time,the quality and oil content of silkworm chrysalis showed a downward trend;the protein content of the main protein molecular weight range of～30 k Da and～70 k Da decreased;the protein content of～70 k Da in silk reeling silkworm chrysalis was rich,which was higher than that in storage period;the first limiting amino acid was leucine;the content of palmitic acid,stearic acid,oleic acid,linoleic acid and linoleic acid in SPO was higher than that in storage period The content ofα-linolenic acid of SPO（30.46±1.18%）was higher than that of SPO（26.03±0.28～28.49±1.84%）.The IC50of DPPH radical and ABTS+·scavenging rate of pupa oil during storage were 20.93～52.00 mg/ml and 33.32～156.81 mg/ml,respectively.The antioxidant activity in vitro might be related to the content of total phenols（15.95±0.28～77.50±1.58 mg/kg oil）.（2）Antioxidant activity of silk reeling SPO in vivo.Compared with the control group,the life extension rate of wild-type C.elegans was increased by 11.91%～18.03%,and the protective effect of SPO on oxidative damage induced by juglone was dose-dependent.After72 hours of administration,ROS content in Low,medium and high SPO groups decreased in a dose-dependent manner,which may be related to the increase of T-SOD activity（increased by13.51%,73.52%,and 108.82%）,CAT activity（increased by 26.52%,41.61%,and 11.43%）,and the decrease of MDA content（decreased by 23.65%,20.91%,and 3.42%）.q RT-PCR was used to detect the m RNA expression level of antioxidant genes.It was found that under normal physiological conditions,SPO group up-regulated the m RNA expression levels of sod-2,daf-2,and skn-1 by 1.13,1.27,and 1.39 times,respectively,and down regulated the m RNA expression levels of sod-3 and ctl-2 by 59.1%and 18.5%,respectively.SPO had no significant effect on the m RNA expression of daf-16（P>0.05）（3）Study on the lipid-lowering activity of silk reeling SPO in vivo.SPO reduced triglyceride content in a dose-dependent manner.Compared with the model control group,the triglycerides of nematodes in the experimental groups fed with 0.05 mg/m L,0.1 mg/m L and 0.5 mg/m L SPO decreased by 21.73%,39.07%and 51.85%,respectively.The m RNA expression levels of fat metabolism related genes were detected by q RT-PCR.It was found that SPO could reduce the m RNA expression levels of fat-5,fat-6,fat-7,nhr-80,and acs-2,up-regulate the m RNA expression levels of age-1 and tph-1,but had no significant effect on the expression levels of mdt-15 and sbp-1（P>0.05）.The lipid-lowering regulation of SPO may be related to age-1,tph-1,and nhr-80 pathways,and the expression of three fatty acid desaturases may be regulated by nhr-80.（P>0.05）... |
