Dietary Supplementation with Hazelnut Oil Reduces Serum Hyperlipidemia and Ameliorates the Progression of Nonalcoholic Fatty Liver Disease in Hamsters Fed a High-Cholesterol Diet

Objective: Hazelnut oil (HO) is rich in monounsaturated fatty acids and polyunsaturated fatty acids. This study intended to analyze the effects of hazelnut oil supplementation on the serum lipid profile and nonalcoholic fatty liver disease in hamsters fed a high-cholesterol (HC) diet. Methods: Hamsters were fed a basic diet (control group) and an HC diet (HC group) for 16 weeks (n = 10 in each group). Hamsters were fed an HC diet for four weeks to induce hyperlipidemia and were then fed an HC diet enriched with 5% (low-dose HC + HO group; n = 10) and 10% HO (high-dose HC + HO group; n = 10) for 12 weeks. Serum lipid levels, hepatic changes (including steatosis, inflammation, and fibrosis), and hepatic prooxidant-antioxidant status (malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST)) were evaluated after the treatment period. Results: Hamsters in the control group showed normal serum lipid profiles, normal liver function, and moderate glycogen storage without hepatic steatosis. Hamsters in the HC group showed severe hyperlipidemia, severe hepatic steatosis, and moderate steatohepatitis (mononuclear cell and neutrophil infiltration, oval cell hyperplasia, and fibrosis). Compared to the HC group, both the low-dose and the high-dose HC + HO groups showed a significant reduction of hyperlipidemia (serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and very-low-density lipoprotein cholesterol (VLDL-C levels)) and improved liver function (serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT)). Additionally, compared to the HC group, intrahepatic triglyceride accumulation (IHTC) was significantly higher in the HC + HO group, while the incidence of steatohepatitis was significantly lower. The intake of the HC diet was associated with a higher level of lipid peroxidation (malondialdehyde, MDA) and a lower concentration of hepatic antioxidant enzymes (SOD, GPx, and GST), and all these factors were partially improved in the low-dose and high-dose HC + HO groups. Conclusions: Our findings indicate that the intake of HO reduced serum hyperlipidemia and oxidative stress and ameliorated the progression of nonalcoholic fatty liver disease in hamsters fed a high-cholesterol diet.

The use of oxidative stress biomarkers in live animals (in vivo) to predict meat quality deterioration postmortem (in vitro) caused by changes in muscle biochemical components

This study was conducted to determine whether circulating concentrations of blood isoprostanes can be used as an effective biomarker in lambs to predict degradation of color and/or lipid stability in meat. Lambs ( = 84) were fed diets of either lucerne pasture, annual ryegrass pasture, a commercial feedlot pellet, or a combination of annual ryegrass and feedlot pellet for 8 wk, including a 2-wk adaptation period. Blood isoprostane concentration at wk 0, 4, 6 or 8 of feeding was determined. Blood isoprostane concentration for each animal was then correlated with muscle biochemical components that impact color and/or lipid oxidative status during retail display. This included lipid oxidation levels in muscle assessed by thiobarbituric acid reactive substances and meat redness determined by a HunterLab colorimetric spectrometer. Lambs that consumed the commercial feedlot pellet had a lower muscle vitamin E level (< 0.01) and a greater level of -6 PUFA ( < 0.001) compared with lambs finished on annual ryegrass or lucerne. Lipid oxidation levels were greatest for lambs finished on the feedlot ration, lowest in lambs finished on the ryegrass diet, and intermediate for lambs finished on lucerne and ryegrass-feedlot combination ( < 0.01). After 8 wk of feeding, blood isoprostane concentration was positively correlated with lipid oxidation of meat displayed for 72 h in simulated retail conditions ( < 0.01). There was a negative linear relationship between isoprostane concentration and muscle vitamin E concentration ( = 0.07), lipid oxidation and muscle vitamin E concentration ( < 0.01) but a positive linear relationship between isoprostane concentration and muscle -6 PUFA ( < 0.001) or lipid oxidation and muscle -6 PUFA concentration ( < 0.001). Blood isoprostane concentration and lipid oxidation in meat were influenced by muscle vitamin E and -6 PUFA but not by -3 PUFA. There was no significant relationship observed between blood isoprostane concentration at 0, 4, 6 or 8 wk feeding vs. overall meat color (redness of meat) at 0 and 72 h of display, stored under simulated retail conditions. The results indicate that circulating blood isoprostane concentration can be a useful tool to predict the oxidative status of postmortem meat. Future work will examine the impact of this relationship on meat flavor/aroma deterioration post farm.

Effect of dietary supplementation with olive and sunflower oils on lipid profile and liver histology in rats fed high cholesterol diet

OBJECTIVE

To compare the effects of high-monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) against the metabolic disorders elicited by a high-cholesterol diet (HC) in rats.

METHODS

Using in vivo dietary manipulation, rats were fed with different diets containing 4% soybean oil (cholesterol free diet) and 1% HC containing 12% olive oil (HC + OO) enriched with MUFA and 12% sunflower oil (HC + SO) enriched with PUFA for 60 d. Serum lipid levels and hepatic steatosis were evaluated after the treatment period.

RESULTS

Comparatively, rats treated with HC + OO diet experienced a decrease in the serum LDL-C, VLDL-C and CT levels compared to those fed with HC + SO diet (P < 0.05). Otherwise, HC + OO provoked significant microvesicular steatosis situated in the hepatic acinar zone 1.

CONCLUSIONS

HC + OO diet has high absorption velocity in the acinar zone 1 of liver compared to the HC + SO diet. Based on this, the reduction of the LDL-C, VLDL-C and CT serum levels in the animals treated with HC + OO diet may have been caused by the delay in the FA release to the blood.

Diet containing partially hydrogenated vegetable fat enhances the carrageenan induced paw inflammation but not oxidative stress markers in liver of rats

In the present study, we investigated the effect of feeding Partially hydrogenated vegetable fat (PHVF) on carrageenan induced paw inflammation and oxidative stress markers in liver of rats. In addition, the effect of feeding rats with Linseed Oil (LSO, α-linolenic acid, n-3 PUFA) or PHVF blended with incremental amounts of LSO on these markers were also monitored. Rats weighing 200 g were given 1 mL of different oils (PHVF, Groundnut Oil; GNO, Olive Oil; OO and LSO) per day for 15 days. Rats given PHVF showed higher levels of paw inflammation in response to carrageenan injection. Rats given LSO showed least amounts of paw inflammation when injected with carrageenan. A second set of experiment was conducted by feeding weaning rats with AIN-93 purified diet supplemented with PHVF or PHVF with incremental amounts of LSO for 60 days. The rats fed PHVF showed higher degree of carrageenan induced inflammation as compared to rats given GNO and LSO. However, the rats fed PHVF showed lower levels of lipid peroxides, protein carbonyls, 8-hydroxy guanine and antioxidant enzyme activities in liver homogenate as compared to those given LSO. In conclusion dietary PHVF rendered the rats prone to higher levels of carrageenan induced inflammation which can be reduced by giving PHVF blended with LSO. However, oxidative stress markers found to be higher levels in rats given LSO or PHVF blended with LSO as compared to rats given PHVF as sole source of fat.