Soy Protein and Fish Oil Independently Decrease Serum Lipid Concentrations but Interactively Reduce Hepatic Enzymatic Activity and Gene Expression Involved in Fatty Acid Synthesis in Rats

Phytic acid actions on hepatic lipids and gut microbiota in rats fed a diet high in sucrose is influenced by dietary fat level

Phytic acid (PA) or myoinositol intake was recently reported by our group to suppress hepatic lipogenic gene expression and modulate gut microbiota in rats fed a high-sucrose diet (HSC). The aim of this study was to investigate the effect of PA and dietary fat level on fatty liver and gut microbiota in rats fed an HSC diet. Male Sprague-Dawley rats were fed a high-fat (HF), HSC diet or a low-fat (LF), HSC diet with or without 1.02% sodium PA for 12 days. Hepatic lipid levels, hepatic enzyme activity, and expression of the enzymes and transcriptional factors related to lipid metabolism, cecal organic acids, and fecal microbiota were evaluated. PA intake depressed hepatic total lipid and triglyceride levels; reduced hepatic activity and expression of lipogenic enzymes; elevated fecal proportion of Lactobacillus spp; and increased cecal succinate level in rats fed the LF diet. The HF diet, when compared with the LF diet, depressed hepatic total lipid and triglyceride levels; reduced hepatic activity and expression of lipogenic enzymes; increased hepatic expression of carnitine palmitoyl-transferase 1a and cAMP-responsive element binding protein 3-like 3; and elevated fecal proportions of Lactobacillus spp and Bifidobacterium spp. In the HF diet groups, PA intake did not affect the factors associated with hepatic lipid metabolism and gut microbiota. In conclusion, dietary fat level could change the effect of PA on hepatic lipid metabolism and gut microbiota and, in turn, could alter the degree of nutritional importance of PA in rats fed an HSC diet.

Intake of phytic acid and myo-inositol lowers hepatic lipogenic gene expression and modulates gut microbiota in rats fed a high-sucrose diet

Dietary phytic acid (PA) was recently reported by our group to suppress hepatic lipogenic gene expression and modulate gut microbiota in rats fed a high-sucrose (HSC) diet. The present study aimed to investigate whether the modulatory effects of PA depend on the dietary carbohydrate source and are attributed to the myo-inositol (MI) ring of PA. Male Sprague-Dawley rats were fed an HSC or a high-starch (HSR) diet with or without 1.02% sodium PA for 12 days. Subsequently, the rats were fed the HSC diet, the HSC diet containing 1.02% sodium PA or an HSC diet containing 0.2% MI for 12 days. The HSC diet significantly increased the hepatic triglyceride (TG) concentration as well as the activity and expression of hepatic lipogenic enzymes compared with the HSR diet. The increases were generally suppressed by dietary PA with a concomitant increase in the fecal and cecal ratios of Lactobacillus spp. In rats fed the HSR diet, PA intake did not substantially affect the factors associated with hepatic lipid metabolism or gut microbiota composition. The effects of MI intake were similar to that of PA intake on hepatic lipogenesis and gut microbiota in rats fed the HSC diet. These results suggest that dietary PA downregulates hepatic lipogenic gene expression and modulates gut microbiota composition in rats fed an HSC diet but not in rats fed an HSR diet. The MI ring of PA may be responsible for the effects of PA intake on hepatic lipogenic gene expression and gut microbiota.

Dietary phytic acid prevents fatty liver by reducing expression of hepatic lipogenic enzymes and modulates gut microflora in rats fed a high-sucrose diet

OBJECTIVES

The aim of this study was to investigate the effect of phytic acid (PA) on fatty liver and gut microflora in rats fed a high-sucrose (HSC) diet.

METHODS

Three groups of rats were fed a high-starch (HSR) diet or an HSC diet with or without 1.02% sodium PA for 12 d. We evaluated hepatic weight, total lipids, and triacylglycerol (TG) levels, the activities and expression of hepatic lipogenic enzymes (glucose-6-phosphate dehydrogenase, malic enzyme 1, and fatty acid synthetase), and fecal microflora.

RESULTS

The HSC diet significantly increased hepatic total lipids and TG levels, and the activities and expression of the hepatic lipogenic enzymes compared with the HSR diet. These upregulations were clearly suppressed by dietary PA. Consumption of PA elevated the fecal ratio of Lactobacillus spp. and depressed the ratio of Clostridium cocoides, and suppressed the elevation in the ratio of C. leptum induced by the HSC diet.

CONCLUSION

This work showed that dietary PA ameliorates sucrose-induced fatty liver through reducing the expression of hepatic lipogenesis genes and modulates gut microflora in rats.

The effect of dietary fatty acid composition on the hepatic fatty acid content and plasma lipid profile in rats

The objective of the present study was to evaluate in a model organism the effect of different dietary lipids on plasma concentration of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triacylglycerols (TAG). One hundred adult male rats (Wistar Albino) were divided into 10 groups with 10 animals each and fed for 7 weeks either basic feed mixture (control diet, C) or basic feed mixture with 5% of palm oil (P), safflower oil (SF), salmon oil (S), fish oil (F), Schizochytrium microalga oil (A), and 20% of beef tallow (T; four groups), respectively. The T-groups were fed for another 7 weeks T-, SF-, F- and A-diet, respectively. At the end of both the first and the second 7-week fattening period, plasma lipid concentration and hepatic fatty acid content was determined. Both A and F diets fed for 7 weeks decreased (P < 0.05) plasma TC (0.98 mmol∙l-1) compared to control (1.19 mmol∙l-1). The highest (P < 0.05) plasma TC was established in rats fed for 7 weeks the SF-diet following the previous 7-week T-treatment (2.15 mmol∙l-1). A-diet had the most positive (decreasing) effect on TAG concentrations (0.68–0.86 mmol∙l-1 compared to 1.22 and 2.88 mmol∙l-1 found in the C and T diets, respectively; P < 0.05). Both plasma TC and TAG were in a negative relationship (P < 0.01) with the hepatic eicosapentaenoic acid and docosahexaenoic acid (DHA) contents, respectively. It was concluded that dietary Schizochytrium microalga oil (with high DHA content) may have the potential for decreasing the risk of cardiovascular diseases.