A high-fat diet differentially affects the gut metabolism and blood lipids of rats depending on the type of dietary fat and carbohydrate

High-dose oral contraceptives induce hyperinsulinemia without altering immune activation in diet-induced obesity which persists even following a dietary low-fat diet intervention

Combined oral contraceptives (COCs) are known to cause weight gain and alter metabolic and immunological pathways. However, modifications in arterial or venous thrombotic risk profiles of women of reproductive ages on COC remain unclear. The study aimed at assessing the impact of COC on immune activation in diet-induced obesity. We further established whether the dietary intervention of switching from a high-fat diet (HFD) to a low-fat diet (LFD) attenuates immunological responses. Twenty (n=20) five-week-old female Sprague Dawley rats were randomly divided into two diet groups of HFD (n=15) and LFD (n=5) and were monitored for eight weeks. After eight weeks, animals in the HFD group switched diets to LFD and were randomly assigned to receive high-dose COC (HCOC) or low-dose COC (LCOC) for six weeks. Animals on HFD significantly gained weight and had a higher lee index when compared to the LFD group (p < 0.05). Moreover, the triglyceride-glucose index, insulin, and other metabolic parameters also increased in the HFD group compared to the LFD group (p < 0.001). Consistently, the levels of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α), were elevated in the HFD group when compared to the LFD group (p < 0.05). Upon switching from a high-fat to a low-fat diet, insulin levels persistently increased in animals receiving HCOC treatment compared to the LFD and HFD/LFD groups (p < 0.05). Thus, in a rat model of HFD-feeding, short-term HCOC treatment induces long-term metabolic dysregulation, which persists despite dietary intervention. However, further studies are recommended to confirm these findings.

Altering the ratio of palmitic, stearic, and oleic acids in dietary fat affects nutrient digestibility, plasma metabolites, growth performance, carcass, meat quality, and lipid metabolism gene expression of Angus bulls

This study evaluated the effects of changing the ratio of palmitic, stearic, and oleic acids in dietary fat on nutritional metabolism, growth performance, and meat quality of finishing Angus bulls. Bulls received the following three treatments: (1) a control diet without fat supplement (CON), (2) CON + mixed fatty acid supplement (58% C16:0 + 28% cis-9 C18:1; MIX), (3) CON + saturated fatty acid supplement (87% C16:0 + 10% C18:0; SFA). In summary, both fat treatment diets simultaneously increased saturated fatty acids C16:0 (P = 0.025), C18:0 (P < 0.001) and total monounsaturated fatty acids (P = 0.008) in muscle, thus balancing the ratio of unsaturated to saturated fatty acids in muscle. MIX diet increased the digestibility of dry matter (P = 0.014), crude protein (P = 0.038), and ether extract (P = 0.036). SFA diet increased the daily gain (P = 0.032) and intramuscular fat content (P = 0.043). The high content of C16:0 and C18:0 in the SFA diet promoted weight gain and fat deposition of beef cattle by increasing feed intake, up-regulating the expression of lipid uptake genes and increasing deposition of total fatty acids, resulting in better growth performance and meat quality.

The source of the fat significantly affects the results of high-fat diet intervention

High-fat diet (HFD) is widely used in animal models of many diseases, it helps to understand the pathogenic mechanism of related diseases. Several dietary fats were commonly used in HFD, such as corn oil, peanut oil, soybean oil, sunflower oil, and lard. However, it was reported that different dietary fat could have completely different effects on physiological indicators and the gut microbiome, and the sources of dietary fat used in high-fat diet research have not been comprehensively compared. In this research, we conduct comparative experiments on various sources of dietary fats to test their different effects during the high-fat diet intervention. We investigated the effects of twelve common dietary fats in high-fat diet intervention of mice, body/liver weight changes, four blood lipid indices, and gut microbiome were analyzed. Our results showed that the source of dietary fat used in high-fat diet significantly affects the changes of body/liver weight and triglyceride (TRIG) in the blood. Furthermore, the intervention of canola oil increased the alpha diversity of gut microbiota, and lard has decreased diversity compared with the control group. The composition of saturated fatty acid (SFA) in fat has the most significant effects on the gut microbiome. All dietary fats treatments have an increasing Firmicutes abundance and a reduced Bacteroidetes abundance in gut microbiome, while the canola oil has a slight variation compared to other intervention groups, and the lard group has the largest changes. This study showed that different types of dietary fat have different effects on the body indicators and intestinal microbiota of mice, and canola oil produced less disturbance than other types of dietary fats in high-fat diet.

Lactiplantibacillus plantarum dfa1 Outperforms Enterococcus faecium dfa1 on Anti-Obesity in High Fat-Induced Obesity Mice Possibly through the Differences in Gut Dysbiosis Attenuation, despite the Similar Anti-Inflammatory Properties

Fat reduction and anti-inflammation are commonly claimed properties of probiotics. Lactiplantibacillus plantarum and Enterococcus faecium were tested in high fat-induced obesity mice and in vitro experiments. After 16 weeks of probiotics, L. plantarum dfa1 outperforms E. faecium dfa1 on the anti-obesity property as indicated by body weight, regional fat accumulation, serum cholesterol, inflammatory cytokines (in blood and colon tissue), and gut barrier defect (FITC-dextran assay). With fecal microbiome analysis, L. plantarum dfa1 but not E. faecium dfa1 reduced fecal abundance of pathogenic Proteobacteria without an alteration in total Gram-negative bacteria when compared with non-probiotics obese mice. With palmitic acid induction, the condition media from both probiotics similarly attenuated supernatant IL-8, improved enterocyte integrity and down-regulated cholesterol absorption-associated genes in Caco-2 cell (an enterocyte cell line) and reduced supernatant cytokines (TNF-α and IL-6) with normalization of cell energy status (extracellular flux analysis) in bone-marrow-derived macrophages. Due to the anti-inflammatory effect of the condition media of both probiotics on palmitic acid-activated enterocytes was neutralized by amylase, the active anti-inflammatory molecules might, partly, be exopolysaccharides. As L. plantarum dfa1 out-performed E. faecium dfa1 in anti-obesity property, possibly through the reduced fecal Proteobacteria, with a similar anti-inflammatory exopolysaccharide; L. plantarum is a potentially better option for anti-obesity than E. faecium.

Dietary Fat Effect on the Gut Microbiome, and Its Role in the Modulation of Gastrointestinal Disorders in Children with Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) report a higher frequency and severity of gastrointestinal disorders (GID) than typically developing (TD) children. GID-associated discomfort increases feelings of anxiety and frustration, contributing to the severity of ASD. Emerging evidence supports the biological intersection of neurodevelopment and microbiome, indicating the integral contribution of GM in the development and function of the nervous system, and mental health, and disease balance. Dysbiotic GM could be a contributing factor in the pathogenesis of GID in children with ASD. High-fat diets may modulate GM through accelerated growth of bile-tolerant bacteria, altered bacterial ratios, and reduced bacterial diversity, which may increase the risk of GID. Notably, saturated fatty acids are considered to have a pronounced effect on the increase of bile-tolerant bacteria and reduction in microbial diversity. Additionally, omega-3 exerts a favorable impact on GM and gut health due to its anti-inflammatory properties. Despite inconsistencies in the data elaborated in the review, the dietary fat composition, as part of an overall dietary intervention, plays a role in modulating GID, specifically in ASD, due to the altered microbiome profile. This review emphasizes the need to conduct future experimental studies investigating the effect of diets with varying fatty acid compositions on GID-specific microbiome profiles in children with ASD.

Lactobacillus acidophilus LA5 improves saturated fat-induced obesity mouse model through the enhanced intestinal Akkermansia muciniphila

Obesity, a major healthcare problem worldwide, induces metabolic endotoxemia through the gut translocation of lipopolysaccharides (LPS), a major cell wall component of Gram-negative bacteria, causing a chronic inflammatory state. A combination of several probiotics including Lactobacillus acidophilus 5 (LA5), a potent lactic acid-producing bacterium, has previously been shown to attenuate obesity. However, data on the correlation between a single administration of LA5 versus microbiota alteration might be helpful for the probiotic adjustment. LA5 was administered daily together with a high-fat diet (HFD) for 8 weeks in mice. Furthermore, the condition media of LA5 was also tested in a hepatocyte cell-line (HepG2 cells). Accordingly, LA5 attenuated obesity in mice as demonstrated by weight reduction, regional fat accumulation, lipidemia, liver injury (liver weight, lipid compositions, and liver enzyme), gut permeability defect, endotoxemia, and serum cytokines. Unsurprisingly, LA5 improved these parameters and acidified fecal pH leads to the attenuation of fecal dysbiosis. The fecal microbiome analysis in obese mice with or without LA5 indicated; (i) decreased Bacteroidetes (Gram-negative anaerobes that predominate in non-healthy conditions), (ii) reduced total fecal Gram-negative bacterial burdens (the sources of gut LPS), (iii) enhanced Firmicutes (Gram-positive bacteria with potential benefits) and (iv) increased Verrucomycobia, especially Akkermansia muciniphila, a bacterium with the anti-obesity property. With LA5 administration, A. muciniphila in the colon were more than 2,000 folds higher than the regular diet mice as determined by 16S rRNA. Besides, LA5 produced anti-inflammatory molecules with a similar molecular weight to LPS that reduced cytokine production in LPS-activated HepG2 cells. In conclusion, LA5 attenuated obesity through (i) gut dysbiosis attenuation, partly through the promotion of A. muciniphila (probiotics with the difficulty in preparation processes), (ii) reduced endotoxemia, and (iii) possibly decreased liver injury by producing the anti-inflammatory molecules.

The effect of dietary high energy density and carbohydrate energy ratio on digestive enzymes activity, nutrient digestibility, amino acid utilization and intestinal morphology of weaned piglets

This study evaluated the effect of high or low digestible energy ratio of carbohydrate in a high or normal dietary energy density on performance, amino acid utilization and intestinal functions of weaned piglets. A total of 32 healthy weaners (9.60 ± 0.13 kg) were allocated to two dietary energy densities (3,400 and 3,800 kcal/kg) and two digestible energy ratio of carbohydrate to fat (9:1 and 3:1) in a 2 × 2 factorial arrangement. There were eight piglets per treatment. The feed intake of piglets was significantly increased by dietary high carbohydrate ratio (9:1) (p < 0.01); however, this did not result in improved body weight gain (p > 0.05). The piglets fed high carbohydrate energy ratio had a reduced villus height/crypt depth (VH/CD) ratio in the duodenum (p < 0.05), and dietary high energy density further decreased the VH/CD ratio in the ileum (p < 0.01). In the duodenum, the lymphocyte count was increased by dietary high energy density (p < 0.05), while dietary energy density and carbohydrate energy ratio interacted to increase lymphocyte count in the ileum (p < 0.05). The serum cholesterol, triglyceride and low-density lipoprotein were not significantly affected (p > 0.05), but dietary energy density interacted with dietary energy ratio to increase high-density lipoprotein concentration (p < 0.05) in piglets fed reduced carbohydrate energy ratio. Dietary high energy density reduced energy digestibility (p < 0.05), whereas high carbohydrate energy ratio increased crude protein digestibility in the piglets (p < 0.05). The intestinal sucrase, lactase activities and serum concentrations of histidine, leucine, lysine, methionine, phenylalanine, alanine, glycine, tyrosine and citrulline were higher in the piglets fed dietary increased carbohydrate energy ratio. Oxidative stress markers and volatile fatty acids concentrations were altered by the dietary treatments. It was concluded that dietary high energy density could be detrimental to piglets intestinal functions and that increased carbohydrate energy ratio could affect amino acid utilization and body weight gain in weaner pigs.

High fat diet for induced dyslipidemia and cardiac pathological alterations in Wistar rats compared to Sprague Dawley rats

INTRODUCTION

Wistar and Sprague Dawley (SD) rats are generally used as models for the cholesterol metabolism experiments. They are acceptable to high fat diet-induced disorders with individual variations, including dyslipidemia and abnormal cardiac pathology.

OBJECTIVE

To compare the effects of high fat diet in inducing dyslipidemia and cardiac pathological alterations between Wistar and SD rats.

METHODS

We compared the differences in plasma cholesterol levels and cardiac pathological alterations between Wistar and SD rats of standard diet (3.90 kcal/g) and high fat diet (5.40 kcal/g) after 4 weeks.

RESULTS

SD rats fed with high fat diet showed significantly enhanced LDL concentration and the decreased HDL concentration when compared to Wistar rats. Additionally, SD rats showed cardiac pathological alterations such as infiltration of mononuclear cells referring to inflammatory response and high amounts of perivascular fat playing a key role in the impairment of vascular functions.

CONCLUSIONS

Our results indicate that SD rats may be the more suitable model for dyslipidemia and alteration of cardiac pathology induced by high fat diet.

Butyrate reduces appetite and activates brown adipose tissue via the gut-brain neural circuit

OBJECTIVE

Butyrate exerts metabolic benefits in mice and humans, the underlying mechanisms being still unclear. We aimed to investigate the effect of butyrate on appetite and energy expenditure, and to what extent these two components contribute to the beneficial metabolic effects of butyrate.

DESIGN

Acute effects of butyrate on appetite and its method of action were investigated in mice following an intragastric gavage or intravenous injection of butyrate. To study the contribution of satiety to the metabolic benefits of butyrate, mice were fed a high-fat diet with butyrate, and an additional pair-fed group was included. Mechanistic involvement of the gut-brain neural circuit was investigated in vagotomised mice.

RESULTS

Acute oral, but not intravenous, butyrate administration decreased food intake, suppressed the activity of orexigenic neurons that express neuropeptide Y in the hypothalamus, and decreased neuronal activity within the nucleus tractus solitarius and dorsal vagal complex in the brainstem. Chronic butyrate supplementation prevented diet-induced obesity, hyperinsulinaemia, hypertriglyceridaemia and hepatic steatosis, largely attributed to a reduction in food intake. Butyrate also modestly promoted fat oxidation and activated brown adipose tissue (BAT), evident from increased utilisation of plasma triglyceride-derived fatty acids. This effect was not due to the reduced food intake, but explained by an increased sympathetic outflow to BAT. Subdiaphragmatic vagotomy abolished the effects of butyrate on food intake as well as the stimulation of metabolic activity in BAT.

CONCLUSION

Butyrate acts on the gut-brain neural circuit to improve energy metabolism via reducing energy intake and enhancing fat oxidation by activating BAT.

Onion quercetin monoglycosides alter microbial activity and increase antioxidant capacity

The effects on fermentation processes in the digestive tract, the biochemical parameters and antioxidant capacity of blood in rats fed high-fat diets with quercetin (Q) and quercetin with quercetin monoglycosides (Q+MQ) preparations obtained from onion waste were evaluated. Four groups of eight animals were fed for 4 weeks with a control diet (C), a high-fat diet (HF) and high-fat diets with 0.15% addition of Q and Q+MQ preparations. HF caused an increase in alanine transaminase (ALT), non-high-density lipoprotein (non-HDL) and the atherogenic index AII vs. C and a decrease in the proportion of HDL in total cholesterol (TC). Q and Q+MQ showed a tendency to moderate the values aspartate transaminase (P=.087), ALT (P<.05), TC (P=.068), non-HDL cholesterol (P<.05), triglycerides (P=.064) and the atherogenic index AII (P<.05). Q+MQ significantly increased the activity of α-glucosidase (P<.05 vs. HF), β-glucosidase (P<.05) and β-galactosidase (P<.05 vs. C and Q). Q increased activity of β-glucosidase (P<.001 vs. C and HF). Both increased the activity of β-glucuronidase (P<.05 vs. C and HF). Both increased the antioxidant capacity of the hydrophilic fraction in serum (P<.05 vs. C and HF), and Q enhanced that of the lipid fraction (P<.001). Q preparation contained 70% quercetin, and Q+MQ preparation contained 29% quercetin and 13% quercetin monoglycosides, mainly quercetin-4'-glucoside. Both exhibited high antioxidant capacity. Supplementation with Q and Q+MQ increased the enzymatic activity of the intestinal microbiota and the antioxidant capacity of blood and revealed a tendency to improve the blood lipid profile. MQ were particularly effective in stimulating the bacterial enzymatic activity.

Benefits of Fish Oil Consumption over Other Sources of Lipids on Metabolic Parameters in Obese Rats

This study evaluated the effect of the consumption of different levels and sources of lipids on metabolic parameters of Wistar rats. Animals were fed with high-fat diet (HFD) containing 20% of lard for 12 weeks to cause metabolic obesity. Subsequently, the animals were divided into six groups and were fed diets with lipid concentrations of 5% or 20% of lard (LD), soybean oil (SO) or fish oil (FO), for 4 weeks. Data were submitted to analysis of variance (two-way) followed by Tukey post hoc test (p < 0.05). The groups that consumed FO showed less weight gain and lower serum levels of triacylglycerol (TAG), total cholesterol and fractions, aspartate aminotransferase (AST) activity, atherogenic index, less amount of fat in the carcass, decreased Lee index and lower total leukocyte counting (p < 0.05). These same parameters were higher in LD treatment (p < 0.05). In the concentration of 20%, carcass fat content, blood glucose levels, as well as alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) decreased in FO groups (p < 0.05). The SO group had intermediate results regarding the other two treatments (FO and LD). We concluded that fish oil intake was able to modulate positively the metabolic changes resulting from HFD.

The association between serum 25-hydroxyvitamin D3 concentration and serum lipids in the rural population of China

Background

Vitamin D deficiency is implicated in some diseases, including cardiovascular. Few studies have assessed the correlation between 25-hydroxyvitamin D3 [25(OH) D3] and serum lipids. In this study, we explored the correlation between serum 25(OH) D3 concentrations and serum lipids with a typical sample of the rural population in China.

Methods

Face-to-face research was used to gather some basic information. Fasting serum concentrations of 25-(OH) D3, total cholesterol (TC), triglyceride (TG), HDL cholesterol (HDL-C) and, LDL cholesterol (LDL-C) tested in the laboratory.

Results

The mean of serum 25(OH) D3 level was 28.71 ± 29.29 ng/mL. The results showed that the dyslipidemia was strongly associated with gender (P = 0.031), drinking (P = 0.043), high-fat diet intake (P = 0.017), HDL-C (P<0), TG (P<0), body mass index (BMI) (P<0) and serum 25(OH)D3 levels (P = 0.002). There was a positive correlation between serum 25(OH)D3 and HDL-C (P<0) in all groups. The relationship between 25(OH) D3 and LDL-C (P = 0.024) was discovered only in normal lipid group. The multivariable adjusted odds ratio (95%CI) of hypoalphalipoproteinemia/HDL and dyslipidemia by comparing the sufficiency vs. the deficiency serum 25-(OH) D3 level were 0.31 (0.192, 0.499) (P = 0.001) and 0.52 (0.36, 0.73) (P = 0.005), respectively.

Conclusions

Serum 25(OH) D3 concentrations were associated with the serum lipids level and the association was different in normal serum lipid group and dyslipidemia group. With the increase of serum 25(OH) D3 levels, the incidence of dyslipidemia decreased.

Dietary Supplementation with Raspberry Seed Oil Modulates Liver Functions, Inflammatory State, and Lipid Metabolism in Rats

BACKGROUND

Although raspberry seed oil (RO) is rich in essential fatty acids, there is a lack of experiments assessing benefits of its consumption.

OBJECTIVE

We investigated the effects of dietary supplementation with RO on healthy rats and rats with low-grade systemic inflammation, liver disorders, and dyslipidemia induced by a high-fat/low-fiber (HF/LF) diet.

METHODS

Thirty-two rats were allocated into 4 groups of 8 rats each and fed for 8 wk a control (C; 7% lard and 5% cellulose) or HF/LF (21% lard and 2% cellulose) diet or modifications of these diets in which 7% RO replaced all (C+RO group) or a proportion of (HF/LF+RO group) the lard. Effects of diet and RO and their interaction on bacterial activity and metabolite formations in the distal intestine, liver fat and glutathione concentration, plasma lipid profile, transaminase activities, and plasma concentrations of C-reactive protein (CRP) and tumor necrosis factor α (TNF-α) were tested.

RESULTS

Dietary RO decreased plasma alanine and aspartate transaminase activities (43.4 and 157 vs. 25.6 and 115 U/L, respectively; P < 0.05 and P < 0.005) and plasma TNF-α and triglyceride concentrations (132 pg/mL and 2.07 mmol/L vs. 86.5 pg/mL and 0.99 mmol/L, respectively; P < 0.05). In livers of the C+RO group, the fat concentration was decreased, whereas the glutathione to glutathione disulfide ratio was increased compared with the C group (30.1% and 6.20 μmol/g vs. 23.3% and 7.25 μmol/g, respectively; P ≤ 0.05); however, those differences were not observed between the HF/LF groups (P-interaction < 0.05). In the HF/LF+RO group, the plasma CRP concentration was lower than in the HF/LF group (88.1 vs. 765 pg/mL; P ≤ 0.05) and similar to that in the C and C+RO groups (158 and 128 pg/mL, respectively).

CONCLUSION

Dietary RO improves plasma lipid profile and liver functions and reduces low-grade systemic inflammation in rats; however, the extent of these beneficial effects is partly dependent on the diet type.

Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver

The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose. Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic. Here, we designed a series of four isocaloric diets (HFD, SO-HFD, F-HFD, F-SO-HFD) to investigate the effects of saturated versus unsaturated fat, as well as fructose, on obesity and diabetes. C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD). They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length. While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury. The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight. Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.

Genomic characterization and transcriptional studies of the starch-utilizing strain Bifidobacterium adolescentis 22L

Bifidobacteria are members of the gut microbiota, but the genetic basis for their adaptation to the human gut is poorly understood. The analysis of the 2,203,222-bp genome of Bifidobacterium adolescentis 22L revealed a nutrient acquisition strategy that targets diet/plant-derived glycans, in particular starch and starch-like carbohydrates. Starch-like carbohydrates were shown to support the growth of B. adolescentis 22L. Transcriptome profiling of 22L cultures grown under in vitro conditions or during colonization of the murine gut by RNA sequencing and quantitative real-time PCR assays revealed the expression of a set of chromosomal loci responsible for starch metabolism as well as for pilus production. Such extracellular structures include so-called sortase-dependent and type IVb pili, which may be involved in gut colonization of 22L through adhesion to extracellular matrix proteins.