Effects Of Meat Protein In High-fat Diets On Hepatic Lipid Metabolisim,Adipogenesis And Gut Microbiota In Mice

In contemporary societies,consumption of meat is increasing and the energy intake from meat makes up to the 15%of the daily energy intake,40%of daily protein,and 20%of daily fat,Studies have shown,that high intake of meat especially red meat has been linked to constellation of disorders associated with metabolic syndromes,obesity,Type II diabetes and cardiovascular diseases.Amino acid profile and protein vary with meat species.Therefore,consumption of meat protein from different sources with different levels of fat can have the potential effect on hepatic lipid metabolism,inflammation in adipose tissue,insulin and glucose metabolism and gut microbiota.In this study,we investigated the effects of high-fat diet(HFD)supplemented with different meat proteins on intestinal microorganisms,hepatic lipid accumulation,adipogenesis and metabolic syndrome related markers.1.Effects of protein in high-fat diets on body weight,growth performance and serum lipid profile of C57BL/6J miceIn order to explore the influence of different meat proteins on the physiological response of mice;soybean,chicken and pork proteins either with low fat(12%Kcal)or high fat(60%Kcal)were administered to C57BL/6J mice for 12 weeks.Body weight and daily food intake were measured during the whole feeding period.At the end of the experiment,the changes in body weight,feed intake,organ index(liver,epididymal adipose),cytokines expression and blood biochemical parameters of mice in different diet groups were compared.The results showed that meat proteins with high fat elevated body weight and weight gain in mice.Mice fed high fat beef(HFB)and high fat chicken(HFCH)had significantly heavier body weight than those fed high fat casein and soy(HFC,HFS).Meat protein significantly increased the weight of liver,adipose tissue in comparison with low fat diet(LFD),which may be correlated with feed intake and weight gain.In high fat diet(HFD)fed mice,intake of meat protein diets caused higher IL-1?,TNF-? and IL-6 and leptin,indicating that intake of meat proteins might induce inflammation in the circulation.Therefore,compared with the low fat soybean group,the meat protein groups are more effective in promoting growth of mice.Compared with the low fat group,the meat proteins in high fat are more likely to cause fat deposition.These results suggest that dietary proteins have significant effects on the physiological status and growth performance of mice.2.Beef,casein and soy proteins differentially affect lipid metabolism,triglycerides accumulation and gut microbiota of high fat diet fed C57BL/6J miceConsumption of dietary protein at recommended levels is considered a potential strategy to promote satiety and weight management,but it is little known how dietary protein from different sources affect obesity development,lipid metabolism,and gut microbiota.This study focused on the effects of beef,casein and soy protein diet on lipid metabolism,triglycerides accumulation and microbial diversity in colon of C57BL/6J mice,which were given either low fat diets(12%Kcal)or high-fat diets(60%Kcal)for 12 weeks.Body and liver weight increased significantly in mice fed a beef protein high fat-diet,whereas reduced cumulative energy intake in a soy protein high fat diet(HFS)group.HFBfed mice showed signs of impaired glucose metabolism and insulin resistance along with a significant elevation in the concentration of triglycerides,LDL-cholesterol,total cholesterol,IL1?,TNF?,IL-6,and leptin in serum.HFB also enhanced lipid accumulation in liver with increased activity of genes important for lipogenesis and hepatic cholesterol metabolism.A 16S rRNA gene sequencing indicated that HFD,regardless of proteins,significantly enhanced the ratio of Firmicutes to Bacteroidetesin colonic microbiota.However,compared with LFD independent of proteins,HFB not only reduced the abundance of Akkermansia,but also decreased the abundance of butyrate-producing bacteria such as Anaerotruncus,Butyricicoccus and Lactobacillus(P<0.05)compared with HFS and HFC.Thus,consumption of HFB does not only affect the gut microbiota composition,but also increases the problems related to metabolic syndromes like dyslipidemia,hypercholesterolemia and triglycerides accumulation in liver which leads to systemic inflammation and its associated comorbidities,e.g.impaired glucose metabolism and insulin resistance.3.Meat protein promotes visceral obesity and adiposity by downregulating the adipocyte differentiation and mitochondrial biogenesis in the high fat fed miceWhite adipose tissue(WAT)expands through hypertrophy(increased adipocyte size)and/or hyperplasia(increased adipocyte number).Hypertrophy has been associated with insulin resistance and dyslipidemia independently of body composition and fat distribution.In contrast,hyperplasia protects against metabolic alterations.Insulin resistance and obesity are associated with a reduction of mitochondrial content in various tissues of mammals.Moreover,reduction in the expression of CIDEA and PGC-1? impairs several cellular functions,including mitochondrial biogenesis and insulin-stimulated glucose uptake,two important mechanisms of body adaptation in response to physical exercise.In this study,we compared the effects of dietary protein from diferent sources on the subcutaneous adipose tissue mice whch were fed both HFD and LFD diet.We found that meat protein with high fat diet increased the hypetrophy in white adipose tissue,and reduced the mitochondrial biogenesis in the brown adipose tissue by downregulting the expression of CIDEA,PGC-1?.4.Meat protein in high fat diet induces adipogensis and dyslipidemia by altering gut microbiota and endocannabinoid dysregulation in the adipose tissue of miceEndocannabinoids modulate insulin and adipokine expression in adipocytes through cannabinoid receptors and their levels are elevated during hyperglycemia and obesity,but little is known about how diets affect them.We assessed the effects of dietary casein,chicken,beef and pork proteins in a high-fat diet mode,on endocannabinoids,adipogenesis and biomarkers associated with dyslipemdia.A high-fat beef or chicken diet upregulated cannabinoid 1 receptor,N-acylphosphatidyl ethanolamine-selective phospholipase-D and diacylglycerol lipase a in adipose tissue,and reduced the immunoreactivity of mitochondrial uncoupling protein 1 in brown adipose tissue.In addition,the high fat diets with beef and chicken proteins had a significant impact on adipocyte differentiation and mitochondrial biogenesis in obese mice.A 16SrRNA gene sequencing indicated that highfat diets,regardless of protein source,significantly enhanced the ratio of Firmicutes to Bacteroidetes in colon.Meat proteins in a high-fat diet significantly decreased the relative abundances of Akkermansia and Bifidobacteria but enhanced lipopolysaccharides level in the serum,which promoted the adipogenesis process by causing dysregulation in the endocannabinoid receptors.Consumption of meat protein with high fat induced adiposity,visceral obesity,dyslipidemia,reduced the thermogenesis,and had a distinctive effect on the mitochondrial biogenesis compared to casein protein.