Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors: 2. C18 fatty acids

Glasser, F. P.; Schmidely, Philippe; Sauvant, Daniel; Doreau, M.

doi:10.1017/s1751731108002036

Cited by 104 publications

(112 citation statements)

References 68 publications

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“…Coefficients for all other physical forms of added lipids were not significantly different from that of control diets. Obviously, low BH pc occurred with fat that was already partly saturated or hydrogenated, whereas a high rate of BH occurred on lipids that contained PUFAs, mainly linolenic acid that has the highest BH pc compared with other unsaturated FA (Glasser et al, 2008).…”

Section: Resultsmentioning

confidence: 96%

“…The effect of pH on BH was studied in the companion paper (Glasser et al, 2008). Even in trials where effect of dietary treatments on pH was not significant , variations in BH pc were observed, thus indicating that BH may be affected by changes in microbial populations or in EMPS without a concomitant change in pH.…”

Section: Resultsmentioning

confidence: 99%

“…To be consistent Schmidely, Glasser, Doreau and Sauvant with the approach described in the companion paper (Glasser et al, 2008), and although there is little or no absorption of long-chain FA in the large intestine, we excluded publications that provided duodenal and only faecal flows.…”

Section: Data Selection and Calculationmentioning

confidence: 99%

“…The consequences of changing dietary fat characteristics on BH and EMPS are also quantified. The companion paper (Glasser et al, 2008) focuses on the major saturated and unsaturated forms of C18.…”

Section: Introductionmentioning

confidence: 99%

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Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors. 1. Total fatty acids

Schmidely

Glasser

Doreau

et al. 2008

Animal

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A database built from 95 experiments with 303 treatments was used to quantify the ruminal biohydrogenation (BH) of fatty acids (FA), efficiency of microbial protein synthesis (EMPS), duodenal flow and intestinal absorption of total FA and of FA with 12 to 18 C units, in response to variations in dietary FA content, source or technological treatment of fat supplement. Flows of FA were expressed relative to dry matter intake (DMI) to compile data from bovine and ovine species. BH tended to increase curvilinearly with FA intake, whereas dietary FA did not affect EMPS. A linear relationship between FA intake and duodenal flow of total FA was obtained, with a coefficient of 0.75 6 0.06 g duodenal FA/kg DMI for each g FA intake/kg DMI. Between experiments, positive balances of total FA (intake -duodenum) were related to low EMPS. Relationships between duodenal flows of FA with 12 to 18 C units and their respective intakes were linear, with a coefficient that increased with the number of C units. Duodenal flow of bacterial FA was linearly related to FA intake (coefficient 0.33 6 0.13), whereas contribution of bacterial lipid to duodenal flow decreased as FA intake increased. For each FA with 12 to 16 C units, prediction of FA absorption from its respective duodenal flow was linear. For total FA and FA with 18 C units, apparent absorption levelled off at high duodenal flows. All these relationships were discussed according to current knowledge on microbial metabolism in the rumen and on the intestinal digestibility of FA in the intestine.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Data Selection and Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors. 1. Total fatty acids

Schmidely

Glasser

Doreau

et al. 2008

Animal

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“…The final reduction step is considered rate limiting and therefore trans 18:1 intermediates can accumulate and flow out of the rumen. On most diets, biohydrogenation of LA and LNA varies between 70% and 95% and 85% and 100%, respectively (Doreau and Ferlay, 1994;Glasser et al, 2008c), indicating that with the exception of diets containing marine oils, 18:0 is the major fatty acid leaving the rumen.…”

Section: Ruminal Lipid Metabolismmentioning

confidence: 99%

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

Shingfield

Bernard

Leroux

et al. 2010

Animal

336

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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Assessing rumen biohydrogenation and its manipulation in vivo, in vitro and in situ

Fievez

Vlaeminck

Jenkins

et al. 2007

Euro J Lipid Sci & Tech

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Assessing rumen biohydrogenation and its manipulation in vivo, in vitro and in situReference techniques to study rumen biohydrogenation (BH) rely on the comparison of intake and duodenal or (ab)omasal flows of polyunsaturated fatty acids (PUFA), whereas the net BH of PUFA to their saturated end-products gives a quantitative measure of accumulating BH intermediates. The current review paper aims at evaluating alternative in vivo, in vitro and in sacco techniques to simulate reference in vivo results of unprotected PUFA sources, as well as strategies for overcoming or manipulating BH. In vivo rumen sampling approaches show potential but require further investigation, whereas in sacco results are inappropriate. In vitro 24-h batch incubations and continuous cultures approach in vivo BH of unprotected C 18 PUFA sources and are useful to assess the pH value at which dissociation of calcium salts of fatty acids occurs, but overestimate the degree of rumen inertness of formaldehyde-treated oil(seeds) and marine products. Batch or continuous cultures provide an accurate estimate (0.6) of the proportion of hydrogenated C 18 PUFA that are converted into their saturated end-product, except for incubations with high levels of fermentable substrate (.1.0 g/100 mL) in combination with high amounts of C 18 PUFA (.0.5 mg/mL) or in incubations with EPA and DHA.

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Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors: 2. C18 fatty acids

Cited by 104 publications

References 68 publications

Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors. 1. Total fatty acids

Digestion of fatty acids in ruminants: a meta-analysis of flows and variation factors. 1. Total fatty acids

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

Assessing rumen biohydrogenation and its manipulation in vivo, in vitro and in situ

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