Dietary fatty acids and human health

Even though extensive research has examined the role of nutrition on milk fat composition, there is less information on the impact of forages on milk fatty acid (FA) composition. In the current study, the effect of replacing grass silage (GS) with maize silage (MS) as part of a total mixed ration on animal performance and milk FA composition was examined using eight multiparous mid-lactation cows in a replicated 4 3 4 Latin square with 28-day experimental periods. Four treatments comprised the stepwise replacement of GS with MS (0, 160, 334 and 500 g/kg dry matter (DM)) in diets containing a 54 : 46 forage : concentrate ratio on a DM basis. Replacing GS with MS increased (P , 0.001) the DM intake, milk yield and milk protein content. Incremental replacement of GS with MS in the diet enhanced linearly (P , 0.001) the proportions of 6:0-14:0, decreased (P , 0.01) the 16:0 concentrations, but had no effect on the total milk fat saturated fatty acid content. Inclusion of MS altered the distribution of trans-18:1 isomers and enhanced (P , 0.05) total trans monounsaturated fatty acid and total conjugated linoleic acid content. Milk total n-3 polyunsaturated fatty acid (PUFA) content decreased with higher amounts of MS in the diet and n-6 PUFA concentration increased, leading to an elevated n-6 : n-3 PUFA ratio. Despite some beneficial changes associated with the replacement of GS with MS, the overall effects on milk FA composition would not be expected to substantially improve long-term human health. However, the role of forages on milk fat composition must also be balanced against the increases in total milk and protein yield on diets containing higher proportions of MS.

Section: --mentioning

confidence: 99%

Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition

Kliem

Morgan

Humphries

et al. 2008

“…A high intake (more than 15% of daily energy intake) of saturated fatty acids (SFAs) (mainly myristic, lauric and palmitic acid) is positively associated with coronary heart disease and mortality rate (Rioux and Legrand, 2007). The negative effect of SFA is mediated through increase in blood cholesterol concentrations, especially plasma total and low-density lipoprotein cholesterol (Williams, 2000). Moreover, the diets high in SFA reduce anti-inflammatory properties of high-density lipoprotein (Rioux and Legrand, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…The particular health benefit has been linked to n-3 PUFA which are essential for normal growth and development (Simopoulos, 1991). Long chain n-3 PUFA (docosahexaenoic acid and eicosapentaenoic acid) demonstrated anti-atherogenic, anti-thrombotic, antiinflammatory and immunosuppressive properties in experimental studies in man (Williams, 2000;Garg et al, 2006). In addition to n-3 PUFA an increasing attention has been paid to -E-mail: Olena.…”

Section: Introductionmentioning

confidence: 99%

Effect of dietary fatty acids on expression of lipogenic enzymes and fatty acid profile in tissues of bulls

Herdmann

Nuernberg

Martin

et al. 2010

This study investigated the effects of dietary linolenic acid (C18:3n-3) v. linoleic acid (C18:2n-6) on fatty acid composition and protein expression of key lipogenic enzymes, acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase (SCD) and delta 6 desaturase (Δ6d) in longissimus muscle and subcutaneous adipose tissue of bulls. Supplementation of the diet with C18:3n-3 was accompanied by an increased level of n-3 fatty acids in muscle which resulted in decrease of n-6/n-3 ratio. The diet enriched with n-3 polyunsaturated fatty acids (PUFAs) significantly inhibited SCD protein expression in muscle and subcutaneous adipose tissue, and reduced the Δ6d expression in muscle. There was no significant effect of the diet on ACC protein expression. Inhibition of the Δ6d expression was associated with a decrease in n-6 PUFA level in muscles, whereas repression of SCD protein was related to a lower oleic acid (C18:1 cis-9) content in the adipose tissue. Expression of ACC, SCD and Δ6d proteins was found to be relatively higher in subcutaneous adipose tissue when compared with longissimus muscle. It is suggested that dietary manipulation of fatty acid composition in ruminants is mediated, at least partially, through the regulation of lipogenic enzymes expression and that regulation of the bovine lipogenic enzymes expression is tissue specific.

“…In humans, diet is the major source of C20:5n-3 and C22:6n-3 since endogenous synthesis via C18:3n-3 is limited (Williams, 2000;Burdge and Calder, 2005;Williams and Burdge, 2006). Therefore, there has been increasing interest in enhancing the concentrations of long-chain (C201) n-3 fatty acids in food, including those derived from ruminants, which are consumed more regularly in Western diets compared to the traditional source of long-chain n-3 fatty acids, namely oily fish.…”

Section: Introductionmentioning

confidence: 99%

Effect of fish oil on ruminal biohydrogenation of C18 unsaturated fatty acids in steers fed grass or red clover silages

Lee

Shingfield

Tweed

et al. 2008

Red clover and fish oil (FO) are known to alter ruminal lipid biohydrogenation leading to an increase in the polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) content of ruminant-derived foods, respectively. The potential to exploit these beneficial effects were examined using eight Hereford 3 Friesian steers fitted with rumen and duodenal cannulae. Treatments consisted of grass silage or red clover silage fed at 90% of ad libitum intake and FO supplementation at 0, 10, 20 or 30 g/kg diet dry matter (DM). The experiment was conducted with two animals per FO level and treatments formed extraperiod Latin squares. Flows of fatty acids at the duodenum were assessed using ytterbium acetate and chromium ethylene diamine tetra-acetic acid as indigestible markers. Intakes of DM were higher (P , 0.001) for red clover silage than grass silage (5.98 v. 5.09 kg/day). There was a linear interaction effect (P 5 0.004) to FO with a reduction in DM intake in steers fed red clover silage supplemented with 30 g FO/kg diet DM. Apparent ruminal biohydrogenation of C18:2n-6 and C18:3n-3 were lower (P , 0.001) for red clover silage than grass silage (0.83 and 0.79 v. 0.87 and 0.87, respectively), whilst FO increased the extent of biohydrogenation on both diets. Ruminal biohydrogenation of C20:5n-3 and C22:6n-3 was extensive on both silage diets, averaging 0.94 and 0.97, respectively. Inclusion of FO in the diet enhanced the flow of total CLA leaving the rumen with an average across silages of 0.22, 0.31, 0.41 and 0.44 g/day for 0, 10, 20 or 30 g FO/kg, respectively, with a linear interaction effect between the two silages (P 5 0.03). FO also showed a dose-dependent increase in the flow of trans-C18:1 intermediates at the duodenum from 4.6 to 15.0 g/day on grass silage and from 9.4 to 22.5 g/day for red clover silage. Concentrations of trans-C18:1 with double bonds from D 4-16 in duodenal digesta were all elevated in response to FO in both diets, with trans-11 being the predominant isomer. FO inhibited the complete biohydrogenation of dietary PUFA on both diets, whilst red clover increased the flow of C18:2n-6 and C18:3n-3 compared with grass silage. In conclusion, supplementing red clover silage-based diets with FO represents a novel nutritional strategy for enhancing the concentrations of beneficial fatty acids in ruminant milk and meat.