Dietary gamma-linolenic acid dose-dependently modifies fatty acid composition and immune parameters in rats

Effect of fungal gamma-linolenic acid and beta-carotene containing prefermented feed on immunity and gut of broiler chicken

Gamma-linolenic acid (GLA) is a fatty acid from the ω-6 family. It is able to deliver a wide range of health benefits arising from its anti-inflammatory effects. An insufficient supply of GLA from agricultural and animal sources resulted in the development of a fermentation technique using lower filamentous fungi, which have the ability to accumulate high concentrations of GLA and beta-carotene during solid-state fermentation of cereals. The goal of this study was to observe the influence of the addition of prefermented cereal product, containing high amounts of GLA and beta-carotene, into the feed of broiler chickens on their immune status, and also the number of lactic acid bacteria and enterobacteria in gut content, which has never been studied before. Immunostimulation in the GLA group was manifested by a significant increase in the oxidative burst of phagocytes, CD4+CD8- lymphocytes in blood, and the CD4: CD8 ratio. Upregulation of gene expression for IgA in the GLA group indicates that the B-lymphocytes were stimulated at a local gut level. In the caecum, increased mRNA expression for mucin-2 and insulin-like growth factor was observed in the GLA group, which could contribute mainly to the protection of the intestinal mucosa and to better growth and regeneration of skeletal muscles. Improved immune activation and protection of the intestinal mucosa were subsequently reflected in a change of the microbial composition in gut contents; a significant reduction of enterobacteria occurred after GLA administration. We can conclude that prefermented cereals containing fungal GLA and beta-carotene represent a low-cost supplement for broiler diet having a beneficial health effect.

Plasma n-6 Fatty Acid Levels Are Associated With CD4 Cell Counts, Hospitalization, and Mortality in HIV-Infected Patients

BACKGROUND

Fatty acids, including n-6 series, modulate immune function, but their effect on CD4 cell counts, death, or hospitalization in HIV-infected patients on antiretroviral therapy is unknown.

METHODS

In a randomized trial for effects of multivitamins in HIV-infected patients in Uganda, we used gas chromatography to measure plasma n-6 fatty acids at baseline; determined CD4 counts at baseline, 3, 6, 12, and 18 months; and recorded hospitalization or death events. The associations of fatty acids with CD4 counts and events were analyzed using repeated-measures analysis of variance and Cox regression, respectively.

RESULTS

Among 297 patients with fatty acids measurements, 16 patients died and 69 were hospitalized within 18 months. Except for linoleic acid, n-6 fatty acids levels were positively associated with CD4 counts at baseline but not during follow-up. In models that included all 5 major n-6 fatty acids, age; sex; body mass index; anemia status; use of antiretroviral therapy, multivitamin supplements, and alcohol; and the risk of death or hospitalization decreased significantly with an increase in linoleic acid and gamma-linolenic acid levels, whereas associations for dihomo-gamma-linolenic acid, arachidonic acid, and aolrenic acid were null. The hazard ratios (95% confidence intervals) per 1 SD increase in linoleic acid and gamma-linolenic acid were 0.73 (0.56-0.94) and 0.51 (0.36-0.72), respectively. Gamma-linolenic acid remained significant (hazard ratio = 0.51; 95% confidence interval: 0.35 to 0.68) after further adjustment for other plasma fatty acids.

CONCLUSIONS

Lower levels of gamma-linolenic acid are associated with lower CD4 counts and an increased risk of death or hospitalization. These results suggest a potential for using n-6 fatty acids to improve outcomes from antiretroviral therapy.

Differential effect of corn oil-based low trans structured fat on the plasma and hepatic lipid profile in an atherogenic mouse model: comparison to hydrogenated trans fat

Background

Trans fat are not desirable in many aspects on health maintenance. Low trans structured fats have been reported to be relatively more safe than trans fats.

Methods

We examined the effects of low trans structured fat from corn oil (LC), compared with high trans fat shortening, on cholesterol and fatty acid metabolism in apo E deficient mice which is an atherogenic animal model. The animals were fed a high trans fat (10% fat: commercial shortening (CS)) or a low trans fat (LC) diet for 12 weeks.

Results

LC decreased apo B and hepatic cholesterol and triglyceride concentration compared to the CS group but significantly increased plasma total cholesterol and triglyceride concentration and fecal lipids with a simultaneous increase in HDL-cholesterol level, apo A-I, and the ratio of HDL-cholesterol to total cholesterol (HTR). Reduction of hepatic lipid levels by inclusion of LC intake was observed alongside modulation of hepatic enzyme activities related to cholesterol esterification, fatty acid metabolism and fecal lipids level compared to the CS group. The differential effects of LC intake on the plasma and hepatic lipid profile seemed to be partly due to the fatty acid composition of LC which contains higher MUFA, PUFA and SFA content as well as lower content of trans fatty acids compared to CS.

Conclusions

We suggest that LC may exert a dual effect on plasma and hepatic lipid metabolism in an atherogenic animal model. Accordingly, LC, supplemented at 10% in diet, had an anti-atherogenic effect on these apo E^-/- mice, and increased fecal lipids, decreased hepatic steatosis, but elevated plasma lipids. Further studies are needed to verify the exact mode of action regarding the complex physiological changes and alteration in lipid metabolism caused by LC.

Dietary effect of pomegranate seed oil on immune function and lipid metabolism in mice

OBJECTIVES

We evaluated the effects of dietary pomegranate seed oil (PSO), which contains high levels of punicic acid (9c, 11t, 13c-octadecatrienoic acid), on immune function and lipid metabolism in C57BL/6N mice.

METHODS

Mice were fed experimental diets containing 0%, 0.12%, or 1.2% PSO for 3 wk.

RESULTS

No significant differences were observed between growth patterns of the experimental groups. Splenocytes isolated from mice fed 0.12% or 1.2% PSO produced larger amounts of immunoglobulins G and M but not immunoglobulin A irrespective of stimulation with or without phorbol 12-myristate 13-acetate and the calcium ionophore A23187. Dietary PSO did not affect the percentages of B cells or CD4-positive or CD8-positive T cells in splenocytes. Levels of interleukin-4, interferon-gamma, and tumor necrosis factor-alpha production from splenocytes were comparable among all dietary groups. Analysis of serum lipid parameters showed significant increases in serum triacylglycerol and phospholipid levels but not in total cholesterol in the PSO groups. Serum, liver, epididymal, and perirenal adipose punicic acid levels were high with increases in dietary PSO level. However, punicic acid was not detected in splenocytes for any dietary group. Interestingly, 9c, 11t-conjugated linoleic acid level could be detected in serum, liver, and adipose tissues in mice fed the 0.12% or 1.2% PSO diet.

CONCLUSIONS

These results suggest that PSO may enhance B-cell function in vivo.