Linoleic and alpha-linolenic acids differently modify the effects of elaidic acid on polyunsaturated fatty acid metabolism and some immune indices in rats

Ruminant fat intake improves gut microbiota, serum inflammatory parameter and fatty acid profile in tissues of Wistar rats

This study tested the hypothesis that naturally and industrially produced trans-fatty acids can exert distinct effects on metabolic parameters and on gut microbiota of rats. Wistar rats were randomized into three groups according to the diet: CONT-control, with 5% soybean oil and normal amount of fat; HVF-20% of hydrogenated vegetable fat (industrial); and RUM-20% of ruminant fat (natural). After 53 days of treatment, serum biochemical markers, fatty acid composition of liver, heart and adipose tissue, histology and hepatic oxidative parameters, as well as gut microbiota composition were evaluated. HVF diet intake reduced triglycerides (≈ 39.39%) and VLDL levels (≈ 39.49%). Trans-fatty acids levels in all tissue were higher in HVF group. However, RUM diet intake elevated amounts of anti-inflammatory cytokine IL-10 (≈ 14.7%) compared to CONT, but not to HVF. Furthermore, RUM intake led to higher concentrations of stearic acid and conjugated linoleic acid in all tissue; this particular diet was associated with a hepatoprotective effect. The microbial gut communities were significantly different among the groups. Our results show that ruminant fat reversed the hepatic steatosis normally caused by high fat diets, which may be related to the remodelling of the gut microbiota and its anti-inflammatory potential.

Lipids and immunology

Dietary fat plays an important regulatory role in the pathogenesis of a range of immune reactions. In food allergies, especially in type I allergic reactions, dietary fat can modulate the development of clinical symptoms through influencing the production of immunoglobulins (Ig), cytokines and chemical mediators. In general, polyunsaturated fatty acids (PUFA) of the n-3 family in relation to those of the n-6 family reduce the production of eicosanoids and hence, mitigate hypersensitivity. In this context, it is interesting that conjugated derivatives of linoleic acid (CLA) reduce the production of eicosanoids and regulate the production of Ig in a manner favourable to the prevention of allergic reactions. Trans monoene fatty acid (that is, elaidic acid), in relation to cis monoenoic fatty acid (that is, oleic acid), also behaves as an anti-allergic agent through interfering with the desaturation of linoleic acid. The information available indicates that different dietary fats influence differently the immune indices related to food allergic reaction. The effects appeared to be readily modified by the combination of food components, including dietary fats. Thus, an appropriate combination of a specific fat or fatty acid may be one approach to the regulation of allergic reaction.

Effect of Dietary Vanaspati Alone and in Combination with Stressors on Sero-biochemical Profile and Immunity in White Leghorn Layers

A total of 160 White Leghorns of 20 wk age were divided randomly into eight groups. Groups 1, 3, 4 and 5 were fed basal feed and the rest were fed 5% vanaspati supplemented feed until 42 wk of age. From 42 to 54 wk, groups 3, 4 and 5 were fed 1% ferrous sulfate, 100 ppm chlorpyrifos (CPS) and 100 ppm cadmium, respectively, along with basal feed and groups 6, 7 and 8 were fed similar stressors, respectively, along with 5% vanaspati. Groups 1 and 2 served as controls for basal feed and 5% vanaspati feed. Alkaline phosphatase (ALP), alanine transaminase (ALT), total protein, albumin, globulin, A/G ratio, total cholesterol, high density cholesterol (HDL), triglycerides, creatinine, hemagglutination inhibition (HI) titer, and phytohemagglutination (PHA) index were studied. Supplementation of vanaspati resulted in a significant reduction in PHA, cholesterol, albumin and HI titer. Cadmium significantly increased ALP, AST, creatinine and paradoxically increased HDL cholesterol and HI titers. Vanaspati along with cadmium showed similar effects. Administration of CPS lowered PHA index, whereas supplementation along with vanaspati decreased the HI titers and increased the PHA index. Supplementation of vanaspati alone and in combination revealed harmful effects and aggravated the toxicities of CPS and cadmium. Hence, it is concluded that consumption of vanaspati could be harmful.

Impact of PUFA on early immune and fetal development

It has recently been reported that the increased prevalence in childhood allergy may be linked to deviations in fetal immune development. One reason may be impaired nutrient supply. Hence, a well-differentiated placenta together with an optimal fetal nutrition via the mother are important prerequisites for the establishment of a functional immune system with normal immune responses. Fatty acids and their derivatives can influence both the early immune development and immune maturation by regulating numerous metabolic processes and the gene expression of important proteins such as enzymes and cytokines. The present review summarises the impact of nutritional fatty acids on the development of the immune system as well as the fetal development. It describes the mechanisms of action of PUFA, trans fatty acids and conjugated linoleic acids in programming the fetus with regard to its risk of acquiring atopic diseases in childhood.

Effect of a mixture of conjugated linoleic acid isomers on growth performance and antibody production in broiler chicks

The effect of dietary conjugated linoleic acid (CLA) isomers mixture on antibody titres against sheep blood erythrocytes (SRBC) and immunoglobulin (Ig) G concentration in plasma was studied in broiler chickens. In experiment 1, male and female broiler chicks (11 d of age, Cobb strain) were fed a diet supplemented with 10 g CLA or 10 g safflower-seed oil/kg diet for 2 weeks. An SRBC suspension (5:100, v/v) in a phosphate buffer was intravenously injected at 18 d of age and a blood sample was taken from the wing vein at 25 d of age. Chicks fed the CLA-supplemented diet had enhanced first antibody titres in plasma to SRBC as compared with those fed the safflower-seed oil-supplemented diet, irrespective of sex differences. In experiment 2, male broiler chicks (8 d of age, Ross strain) were fed a basal diet or a diet containing 10 g CLA/kg diet for 3 weeks. CLA in the CLA diet partially replaced the soyabean oil in the basal diet. The SRBC suspension was intravenously injected at 15 and 25 d of age and a blood sample was obtained at 21 and 29 d of age. The first antibody titres against SRBC were higher in chicks fed the CLA diet than those in chicks fed the basal diet, but the second titres were not. Plasma IgG concentrations in chicks fed the CLA diet were higher than those in chicks fed the basal diet on both sampling days. The results showed that dietary CLA enhanced antibody production in broiler chickens.

Dietary linoleic acid divergently affects immune responsiveness of growing layer hens

The effects of linoleic (LA)- and linolenic acid (LNA)-enriched diets on humoral and in vivo cellular immune responses to keyhole limpet hemocyanin (KLH)-dinitrophenyl (DNP) and Mycobacterium butyricum were studied in growing layer hens. Pullets were fed one of three diets: a control, LA enriched, or LNA enriched. Pullets were assigned to one of three immunization treatments: KLH-DNP, M. butyricum, or PBS. The LA-enriched diet enhanced the antibody response to KLH in pullets immunized with KLH-DNP. On the other hand, the antibody response to M. butyricum in M. butyricum-immunized birds was decreased by feeding an LA-enriched diet. In vitro lymphocyte proliferation in the presence of Concanavalin A was affected by the interaction between diet and immunization. Neither cutaneous hypersensitivity to KLH nor to M. butyricum was affected by the diet. The BW gain before immunization was not affected by the diet, but after immunization, the LA-enriched diet enhanced growth in birds immunized with M. butyricum. Diets had various effects on organ weights. We concluded that dietary linoleic acid enrichment of the diet has an antigen-dependent divergent effect on the antibody response. The dietary LNA effect on the antibody response is less pronounced and is opposite to that of the LA effect.