Biosynthesis of Conjugated Linoleic Acid in Ruminants and Humans

Palmquist, D.L.; Lock, A.L.; Shingfield, Kevin J.; Bauman, Dale E.

doi:10.1016/s1043-4526(05)50006-8

Cited by 272 publications

(312 citation statements)

References 136 publications

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“…Following ingestion, ester linkages in triacylglycerides (TAG), phospholipids and glycolipids are hydrolyzed by the action of bacterial lipases and the non-esterified fatty acids (NEFA) released into the rumen are adsorbed onto feed particles and biohydrogenated or incorporated directly into bacterial lipids. Numerous in vitro and in vivo studies have allowed the major pathways of ruminal biohydrogenation to be elucidated (Harfoot and Hazlewood, 1988;Palmquist et al, 2005;Jenkins et al, 2008). Metabolism of linoleic acid (LA; cis-9, cis-12 18:2) and linolenic acid (LNA; cis-9, cis-12, cis-15 18:3) is considered to involve at least two distinct populations of ruminal bacteria that under normal conditions is thought to proceed via isomerization of the cis-12 double bond resulting in the formation of a conjugated 18:2 or 18:3 fatty acid, respectively.…”

Section: Ruminal Lipid Metabolismmentioning

confidence: 99%

“…1.14.99.5), often referred to as D-9 desaturase, an enzyme that catalyses the oxidation of fatty acyl CoA esters resulting in the introduction of a cis double bond between carbon atoms 9 and 10. The SCD catalyzed reaction involves cytochrome b 5 , NAD(P)-cytochrome b 5 reductase and molecular oxygen and the CoA ester of fatty acids as a substrate (Palmquist et al, 2005). Activity of SCD in the ruminant mammary gland is thought to occur as a mechanism to maintain and regulate the fluidity of milk to ensure efficient ejection from the mammary glands (Timmen and Patton, 1988).…”

Section: Mammary Lipogenesismentioning

confidence: 99%

“…Activity of SCD in the ruminant mammary gland is thought to occur as a mechanism to maintain and regulate the fluidity of milk to ensure efficient ejection from the mammary glands (Timmen and Patton, 1988). Stearoyl and palmitoyl-CoA are the preferred substrates for SCD with 18:0 to OA being the predominant precursor:product of SCD in the bovine mammary epithelial cell (bMEC) (Palmquist et al, 2005;Bernard et al, 2008). Between 49% and 60% of 18:0 available for mammary TAG synthesis is desaturated with the extent of endogenous conversion accounting for ca.…”

Section: Mammary Lipogenesismentioning

confidence: 99%

“…A number of other saturated acyl CoA also serve as substrates for SCD including 10:0, 12:0, 14:0, 15:0 and 17:0 (Bauman and Davis, 1974;Shingfield et al, 2008c). Endogenous synthesis via the action of SCD on trans-11 18:1 is responsible for 64% to 97% of cis-9, trans-11 CLA (Palmquist et al, 2005;Glasser et al, 2008b) and virtually all the trans-7, cis-9 CLA secreted in bovine milk (Palmquist et al, 2005). Experiments with 13 C-labelled trans-11 18:1 have estimated that 25% or 32% is desaturated to cis-9, trans-11 CLA in the bovine (Mosley et al, 2006) and caprine (Bernard et al, 2010) mammary gland, respectively.…”

Section: Mammary Lipogenesismentioning

confidence: 99%

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Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Shingfield

Bernard

Leroux

et al. 2010

Animal

327

427

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Fat is an important constituent contributing to the organoleptic, processing and physical properties of ruminant milk. Understanding the regulation of milk fat synthesis is central to the development of nutritional strategies to enhance the nutritional value of milk, decrease milk energy secretion and improve the energy balance of lactating ruminants. Nutrition is the major environmental factor regulating the concentration and composition of fat in ruminant milk. Feeding low-fibre/high-starch diets and/or lipid supplements rich in polyunsaturated fatty acids induce milk fat depression (MFD) in the bovine, typically increase milk fat secretion in the caprine, whereas limited data in sheep suggest that the responses are more similar to the goat than the cow. Following the observation that reductions in milk fat synthesis during diet-induced MFD are associated with increases in the concentration of specific trans fatty acids in milk, the biohydrogenation theory of MFD was proposed, which attributes the causal mechanism to altered ruminal lipid metabolism leading to increased formation of specific biohydrogenation intermediates that exert anti-lipogenic effects. Trans-10, cis-12 conjugated linoleic acid (CLA) is the only biohydrogenation intermediate to have been infused at the abomasum over a range of experimental doses (1.25 to 14.0 g/day) and shown unequivocally to inhibit milk fat synthesis in ruminants. However, increases in ruminal trans-10, cis-12 CLA formation do not explain entirely diet-induced MFD, suggesting that other biohydrogenation intermediates and/or other mechanisms may also be involved. Experiments involving abomasal infusions (g/day) in lactating cows have provided evidence that cis-10, trans-12 CLA (1.2), trans-9, cis-11 CLA (5.0) and trans-10 18:1 (92.1) may also exert anti-lipogenic effects. Use of molecular-based approaches have demonstrated that mammary abundance of transcripts encoding for key lipogenic genes are reduced during MFD in the bovine, changes that are accompanied by decrease in sterol response element binding protein 1 (SREBP1) and alterations in the expression of genes related to the SREBP1 pathway. Recent studies indicate that transcription of one or more adipogenic genes is increased in subcutaneous adipose tissue in cows during acute or chronic MFD. Feeding diets of similar composition do not induce MFD or substantially alter mammary lipogenic gene expression in the goat. The available data suggests that variation in mammary fatty acid secretion and lipogenic responses to changes in diet composition between ruminants reflect inherent interspecies differences in ruminal lipid metabolism and mammary specific regulation of cellular processes and key lipogenic enzymes involved in the synthesis of milk fat triacylglycerides.Keywords: milk fat, trans fatty acids, gene expression, lipogenesis, ruminants ImplicationsUnderstanding the regulation of milk fat synthesis is central to the development of nutritional strategies to enhance the nutritional value of milk, decrease milk-energ...

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Section: Ruminal Lipid Metabolismmentioning

confidence: 99%

Section: Mammary Lipogenesismentioning

confidence: 99%

Section: Mammary Lipogenesismentioning

confidence: 99%

Section: Mammary Lipogenesismentioning

confidence: 99%

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Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Shingfield

Bernard

Leroux

et al. 2010

Animal

327

427

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“…FO is also known to inhibit the complete biohydrogenation of C18 PUFA to C18:0 resulting in an accumulation of trans-11 C18:1 (Shingfield et al, 2003, Lee et al, 2005, Loor et al, 2005b. This particular fatty acid is consequently available for endogenous conversion to cis-9, trans-11 CLA via the action of stearoyl-CoA desaturase in the mammary gland (Griinari et al, 2000;Palmquist et al, 2005) and explains FO's effect in enhancing cis-9, trans-11 CLA concentration in milk (Offer et al, 1999;Chilliard et al, 2000;Shingfield et al, 2003). Enhancement of CLA in ruminant products (meat and dairy) through dietary manipulation is an important contributor towards the recommended intake of 3 g/day (Roche et al, 2001) as part of a complete diet approach.…”

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

Animal

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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.

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RuminantTransFat as Potential Nutraceutical Components to Prevent Cancer and Cardiovascular Disease

Wang¹,

Field²,

Proctor³

2011

Functional Foods, Nutraceuticals, and Degenerative Disease Prevention

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Biosynthesis of Conjugated Linoleic Acid in Ruminants and Humans

Cited by 272 publications

References 136 publications

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

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

RuminantTransFat as Potential Nutraceutical Components to Prevent Cancer and Cardiovascular Disease

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