Plant polyphenols associated with vitamin E can reduce plasma lipoperoxidation in dairy cows given n-3 polyunsaturated fatty acids

Abstract

Diets rich in n-3 polyunsaturated fatty acids (PUFA) improve the nutritional value of ruminant products but also increase the risk of lipoperoxidation in plasma and tissues. The relative effectiveness of dietary antioxidants such as vitamin E (vit E) given alone or with plant extracts rich in polyphenols (PERP) containing rosemary, grape, citrus, and marigold was investigated in the plasma of mid-lactation dairy cows given diets enriched in 18:3 n-3. For a 30-d period, the animals were given a maize silage-based diet (control group C, n = 6) or the same basal diet supplemented with extruded linseed rich in 18:3 n-3 [50 g of oil/kg of diet dry matter (DM); group L, n = 6], extruded linseed + vit E (375 international units/kg of diet DM; 7,500 IU/cow per day; group LE, n = 6), or extruded linseed + vit E + PERP (10 g/kg of diet DM; group LEP, n = 5). Plasma susceptibility to lipoperoxidation was evaluated using in vitro parameters of conjugated diene formation (lag phase and maximum oxidation rate). Plasma indicators of lipoperoxidation and antioxidant status were analyzed in the 4 experimental groups as well as the fatty acid (FA) composition of total plasma lipids. At d 30, group L significantly increased plasma cholesterol esters (+57%) and phospholipids (+35%) compared with group C. It also increased plasma n-3 PUFA (4.7-fold increase) to the detriment of n-6 PUFA (-30%), leading to a higher peroxidizability index (+20%). Plasma in vitro lipoperoxidation was higher in group L (rich in 18:3 n-3) than in group C. Vitamin E alone had no effect on lipoperoxidation, whereas vit E in association with PERP lowered lipoperoxidation by increasing the resistance time against peroxidation (+47%) and by decreasing the oxidation rate (-48%) compared with group L at d 30. Surprisingly, in vivo plasma lipoperoxidation estimated by the plasma level of the major lipoperoxidation product (malondialdehyde) was not significantly increased in group L. This study shows, for the first time, that PERP supplied in association with vit E were able to reduce lipoperoxidation in lactating cows given a diet rich in 18:3 n-3, thereby helping to protect cows against the deleterious consequences of lipoperoxidation and potentially ensuring antioxidant potential for 18:3 n-3-enriched dairy products.

The liver antioxidant status of fattening lambs is improved by naringin dietary supplementation at 0.15% rates but not meat quality

“…In contrast with previous studies (Gobert et al, 2009), the trend to significance (P 5 0.087) found for the difference in TAG levels between both groups is noteworthy (Figure 2). The naringin-lowering effect on serum TAG levels might be related to an inhibitory effect of flavonoids on DGAT1 activity, one of the main enzymes involved in TAG synthesis in the liver (Casaschi et al, 2002;Jeon et al, 2004).…”

“…0.05) in the average values of total cholesterol, HDL and LDL levels of the serum from lambs in the NARINGIN group when compared with lambs in the CONTROL group is similar to the results reported by Gobert et al (2009), who found no differences in plasma cholesterol and TAG contents in dairy cows when being fed linseed supplemented with plant extracts rich in polyphenols and vitamin E. However, these results seem to differ from the results described in hypercholesterolaemic subjects who consumed naringin (Kim et al, 2004 andBaba et al, 2007), where a reduction in total cholesterol and LDL cholesterol levels plus an increase in HDL cholesterol was observed. This effect was attributed to an inhibitory effect of naringin on HMG-CoA reductase and ACAT, a ratelimiting enzyme of the cholesterol biosynthetic pathway and a cholesterol esterifying enzyme-regulating intracellular cholesterol homeostasis, respectively .…”

“…However, it has been suggested that different antioxidants given alone or combined with vitamin E could be more efficient at enhancing the antioxidant status of animals than the use of large doses of vitamin E (Gladine et al, 2007;Gobert et al, 2009 and.…”

Influence des acides gras polyinsaturés n-3 et des antioxydants alimentaires sur les acides gras de la viande et la lipoperoxydation chez le bovin en finition

“…Effets des AGPI n-3 et des antioxydants alimentaires sur les marqueurs plasmatiques de la lipoperoxydation chez la vache de réforme en finition (Gobert et al, 2009a été déjà montré chez le rat et le mouton (Gladine et al, 2007) ainsi que chez la vache en lactation (Gobert et al, 2009a). Chez la vache de réforme en finition soumise à un stress émo-tionnel deux heures avant l'abattage, le niveau de lipoperoxydation du plasma évalué par le niveau de MDA (tableau 5) n'était pas augmenté dans les lots d'animaux stressés comparés à ceux des lots non stressés.…”

“…Comme décrit précédemment (Gatellier et al, 2000), la vit E apportée seule n'est pas assez efficace pour protéger la viande de la lipoperoxydation chez des bovins recevant des supplé-ments en AGPI n-3. En revanche, comme chez le rat et le mouton (Gladine et al, 2007), et la vache laitière en lactation (Gobert et al, 2009a), l'association de la vit E avec les EVRP exercerait des actions synergiques résultant de leurs propriétés respectives lipophiles (vit E) et hydrophiles (polyphénols). La vit E agirait comme un antioxydant casseur de chaînes, et les polyphé-nols comme piégeurs de radicaux libres.…”