Study On The Regulation Mechanism Of Lipid Metabolism From Large Yellow Croaker (Pseudosciaena Crocea) Roe And Its Application

Large yellow croaker roe phospholipids(LYCRPLs)are of great nutritional value because they are rich in n-3 polyunsaturated fatty acids(n-3 PUFA).In the early stage,our research group studied the effect of LYCRPLs on inhibiting triglyceride enrichment at cellular level,but its effect on the lipid regulation of high-fat diet rats and its impact on intestinal flora and metabolites have not yet been clarified.Therefore,this study used LYCRPLs as experimental material,established a high-fat diet model based on SD rats,and systematically studied the effects and mechanisms of LYCRPLs on lipid regulation in high-fat diet rats.And develop LYCRPLs-casein solid base material,aiming to lay the foundation for the high-value utilization of large yellow croaker roe.The main research contents and results are as follows:(1)Regulation of LYCRPLs on lipid metabolism in rats with high-fat diet.High-fat diet was used to induce the disorder of lipid metabolism in SD rats,and simvastatin,low-dose,medium-dose and high-dose LYCRPLs were given by intragastric administration.After continuous feeding for 8weeks,the SD rats’ body weight,food intake,organ index,blood biochemical indicators,epididymal fat tissue and liver histopathology were compared and analyzed.The results showed that: compared with the control group(K),the weight,organ index,blood cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDL-C)levels in model group(M)significantly increased,high-density lipoprotein cholesterol(HDL-C)levels were significantly reduced,and hepatocytes and epididymal fat particles increased.Compared with group M,the weight gain,TC,TG,and LDL-C levels of group GA,GB,and GC were all suppressed,and HDL-C levels were significantly increased;LYCRPLs can significantly inhibit the growth of liver,perirenal fat,and epididymal fat in experimental rats.The fat content in the liver of group GA,GB,and GC were significantly reduced,the fat particles in the epididymis were significantly reduced,and the boundaries were clear.The suppression effect is better than group Y.The experimental results show that LYCRPLs can significantly regulate lipid metabolism.(2)LYCRPLs regulated lipid metabolism by mediating experimental SD rat intestinal flora.The experiment used high-throughput 16 S r RNA gene sequencing technology,supplemented by bioinformatics analysis technology,to measure and analyze the diversity of intestinal flora in rats.The results showed that after 8 weeks of high-fat diet intervention,compared with group K,the intestinal flora of SD rats in group M had a significant change of 100 OUT,of which 45 were up-regulated and 55 were down-regulated;Compared with group M,group GA significantly changed the richness of 60 OTUs,of which 20 were increased and 40 were decreased;The group GC significantly changed the richness of 91 OTUs,of which 23 were increased and 68 were decreased;Gavage of different doses of LYCRPLs can significantly reduce the abundance of Prevotella,Mucispirillum and Alisipes in feces,and significantly increase the abundance of Bacteroides and Alloprevotella.The experimental results show that LYCRPLs can mediate the intestinal flora to improve the lipid metabolism disorder in SD rats.(3)Based on GC/MS non-targeted metabolomics to study the mechanism of LYCRPLs regulating lipid metabolism.The experiment used GC/MS non-targeted metabolomics to analyze the enrichment of differential metabolites related to lipid metabolism and their metabolic pathways in the rat intestine.The results showed that after 8 weeks of highfat diet intervention,compared with group K,rats in group M had 155 metabolites with significant differences.Compared with group M,group GA had 68 significantly different metabolites,of which 50 were upregulated and 18 were down-regulated;There were 62 significantly different metabolites in group GB,of which 58 were up-regulated and 4were down-regulated;There were 83 significantly different metabolites in group GC,of which 78 were up-regulated and 5 were down-regulated;After intragastric administration of LYCRPLs,the pathways of significant enrichment in their differential metabolites included choline metabolism in cancer,regulation of lipolysis in adipocytes,non-alcoholic fatty liver disease and bile secretion.The pathways are related to lipid metabolism in rats.The experimental results show that LYCRPLs can promote the conversion of lipids and the excretion of metabolites in high-fat diet rats.(4)LYCRPLs-casein emulsification process and solidification application research.In order to improve the utilization level of LYCRPLs,the experiment used LYCRPLs as material to establish a LYCRPLs-casein composite system,and used a low-temperature spray drying method to prepare LYCRPLs-casein solid base material and studied their physical and chemical properties.Based on the single factor experiment,the emulsifying activity was selected as the index for response surface analysis,and the moisture content,angle of repose,bulk density,solubility,peroxide value and microstructure of the powder prepared under the optimized conditions were characterized.The results showed that when the volume ratio of LYCRPLs to casein is 1: 2,the homogeneous pressure is 600 bar(60 MPa),and the oil phase volume is 6 m L,a composite system with emulsification activity index of 49.49 m~2/g can be obtained;The solid base material prepared under this condition is light yellow,with small particles,uniform dispersion,and good water resolubility.Moisture content 1.3%,angle of repose 33.57°,bulk density 0.769 g/cm3,solubility 47.56%,peroxide value1.65 mmol/kg;Scanning electron microscopy showed that the solid matrix structure is dense,non-porous,nearly spherical,slightly concave,and the particle size is between 5-30 μm.