Associations between concentrations of fat and intermediates of ruminal biohydrogenation in milk of dairy cows

Rumen bacteria convert polyunsaturated C18 fatty acids to stearic acid (CI8:0) by biohydrogenation. Intermediates include a family of cis/trans isomers of linoleic acid known as conjugated linoleic acid (CLA) and a family of trans isomers of oleic acid (C18:1), chiefly trans-11 C18:1. Trans fatty acids inhibit milk fat synthesis in cows, an effect which Griinari et al. (1997) attributed specifically to trans-10 C18:1. Biohydrogenation intermediates can be incorporated directly into milk. In humans, trans C18:1 in hydrogenated vegetable oil (chiefly trans-9 C18:1) mimic saturated fatty acids as a risk factor for heart disease (Judd et al., 1994) and may inhibit milk fat synthesis. CLA may be anticarcinogenic (Parodi, 1997). It is important, therefore, to understand the effect of dairy cow nutrition on biohydrogenation intermediates.

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Effect of unsaturated fatty acids and triglycerides from soybeans on milk fat synthesis and biohydrogenation intermediates in dairy cattle

Journal of Dairy Science ◽

10.3168/jds.2014-7966 ◽

2014 ◽

Vol 97 (11) ◽

pp. 7031-7042 ◽

Cited By ~ 21

Author(s):

J.P. Boerman ◽

A.L. Lock

Keyword(s):

Fatty Acids ◽

Dairy Cattle ◽

Milk Fat ◽

Unsaturated Fatty Acids ◽

Fat Synthesis ◽

Biohydrogenation Intermediates ◽

Milk Fat Synthesis

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Diet-induced milk fat depression is associated with alterations in ruminal biohydrogenation pathways and formation of novel fatty acid intermediates in lactating cows

British Journal Of Nutrition ◽

10.1017/s0007114517000010 ◽

2017 ◽

Vol 117 (3) ◽

pp. 364-376 ◽

Cited By ~ 21

Author(s):

Laura Ventto ◽

Heidi Leskinen ◽

Piia Kairenius ◽

Tomasz Stefański ◽

Ali R. Bayat ◽

...

Keyword(s):

Milk Fat ◽

Latin Square ◽

Dimethyl Acetal ◽

Milk Fat Depression ◽

Lactating Cows ◽

Fat Synthesis ◽

Ruminal Biohydrogenation ◽

Biohydrogenation Intermediates ◽

Forage:Concentrate Ratio ◽

Milk Fat Synthesis

AbstractThe biohydrogenation theory of milk fat depression (MFD) attributes decreases in milk fat in cows to the formation of specific fatty acids (FA) in the rumen.Trans-10,cis-12-CLA is the only biohydrogenation intermediate known to inhibit milk fat synthesis, but it is uncertain if increased ruminal synthesis is the sole explanation of MFD. Four lactating cows were used in a 4×4 Latin square with a 2×2 factorial arrangement of treatments and 35-d experimental periods to evaluate the effect of diets formulated to cause differences in ruminal lipid metabolism and milk fat synthesis on the flow of FA and dimethyl acetal at the omasum. Treatments comprised total mixed rations based on grass silage with a forage:concentrate ratio of 35:65 or 65:35 containing 0 or 50 g/kg sunflower oil (SO). Supplementing the high-concentrate diet with SO lowered milk fat synthesis from −20·2 to −31·9 % relative to other treatments. Decreases in milk fat were accompanied by alterations in ruminal biohydrogenation favouring thetrans-10 pathway and an increase in the formation of specific intermediates includingtrans-4 totrans-10-18 : 1,trans-8,trans-10-CLA,trans-9,cis-11-CLA andtrans-10,cis-15-18 : 2. Flow oftrans-10,cis-12-CLA at the omasum was greater on high- than low-concentrate diets but unaffected by SO. In conclusion, ruminaltrans-10,cis-12-CLA formation was not increased on a diet causing MFD suggesting that other biohydrogenation intermediates or additional mechanisms contribute to the regulation of fat synthesis in the bovine mammary gland.

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The effect of trans- 10, cis- 12 conjugated linoleic acid on milk fat synthesis in lactating sheep

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200010036 ◽

2005 ◽

Vol 2005 ◽

pp. 92-92 ◽

Cited By ~ 1

Author(s):

L. A. Sinclair ◽

A. L. Lock ◽

J. W. Perfield ◽

B. M. Teles ◽

D. E. Bauman

Keyword(s):

Linoleic Acid ◽

Conjugated Linoleic Acid ◽

Milk Fat ◽

Milk Protein ◽

Potent Inhibitor ◽

Curvilinear Relationship ◽

Fat Synthesis ◽

Fat Yield ◽

Protein Output ◽

Milk Fat Synthesis

Trans- 10, cis- 12 conjugated linoleic acid (CLA), a biohydrogenation intermediate produced in the rumen, is a potent inhibitor of milk fat synthesis. Data from a number of studies where various doses of trans -10, cis -12 CLA have been abomasally infused demonstrate a curvilinear relationship between the percent reduction in milk fat yield and both the dose of trans- 10, cis- 12 CLA infused and the milk fat content of trans- 10, cis- 12 CLA. In addition to a reduction in milk fat output, under some circumstances an increase in milk yield and milk protein output are observed. To date, there has been no examination of the effects of trans- 10, cis- 12 CLA on milk fat synthesis in lactating sheep. The current study was therefore designed to determine if trans- 10, cis- 12 CLA would inhibit milk fat synthesis in lactating sheep. In order to test the effectiveness of trans- 10, cis- 12 CLA in inhibiting milk fat synthesis we used a lipid-encapsulated trans- 10, cis- 12 CLA supplement (LE-CLA) as a means to provide the trans- 10, cis- 12 CLA isomer post-ruminally.

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