Tom Jenkins, ProfessorDepartment of Animal &Veterinary Sciences

Rumen Transformations of Lipid

Rumen Transformations of LipidReview of Dietary Lipid

Fatty acids are most important lipid fraction.

Majority of fatty acids are bound to glycerol as simple or compound lipids.

Majority of fatty acids are unsaturated.

Rumen Transformations of LipidLearning Objectives

What happens to dietary lipid as it passes from the diet to the intestines and is metabolized by rumen microorganisms?

What are the intermediates and end products that accumulate in the rumen from lipid metabolism?

How does lipid transformations in the rumen affect animal performance?

Rumen Transformations of LipidCompounds Extracted in Fat Test?

Biohydrogenation

Compound

Simple

Lipolysis

MUFA

PUFA

Microbial Lipid Synthesis VFA

Rumen Transformations of LipidHow Does Dietary Lipid Changeas it Passes Through the Rumen?

47.9 lb. DMI60% Forage(mainly corn silage,5 lbs. alfalfa hay)

From CPM for Dairy v.3.0.8

Intake

892 g FA(<10%

FFA)

2 g C18:0

219 g C18:1

440 g C18:2

37 g C18:3

Rumen Transformations of LipidRumen FA Transformations

Outflow

876 g FA

C18:0

C18:1

C18:2

C18:3

From CPM for Dairy v.3.0.8

LargeIntestine

SmallIntestine

Rumen

Omasum

Abomasum

Reticulum

Esophagus

Rumen

CH

H H H H H H H H H H H H H H H H H

C C C C C C C C C C C C C C C C C

H H H H H H H H H H H H H

O

OH

Rumen Transformations of LipidBiohydrogenation

Unsaturated (18:2)

Stearic (18:0)

Rumen Transformations of LipidBiohydrogenation

Unsaturated Fat

H

C

H

C

H H

H

C

H

H

C

H

C

Rumen Transformations of LipidBiohydrogenation

H

C

H

C

H H

H

C

H

H

C

H

C

H H

Rumen Transformations of LipidBiohydrogenation

Saturated Fat

H

C

H

C

H H

H

C

H

H

C

H

C

H H

Rumen Transformations of LipidBiohydrogenation

Unsaturated (18:2)

CLA (18:2)

trans (18:1)

Stearic (18:0)

Rumen Transformations of LipidBiohydrogenation

Unsaturated Fat

H

C

H

C

H

C

H

H

C

H

C

Rumen Transformations of LipidBiohydrogenation

H

C

H

C

H

H

C

H

H

C

H

C

Rumen Transformations of LipidBiohydrogenation

H

C

H

C

H

C

H

H

C

H

C

CLA

Rumen Transformations of LipidCLA Intermediates in Digesta

Linoleic (18:2)

cis–9 trans–11 (18:2)

trans–11 (18:1)

Stearic (18:0)

From Teter, B.B., and T.C. Jenkins. 2006. In Advances in Conjugated Linoleic Acid Research, Vol. 3

t7t9 t8t10 t9t11 t10t12 t11t13 t12t140

102030405060

% of total

t7c9 t8c10 c9t11 t10c12 t11c13 c11t13 c12t140

20

40

60

80

100

Rumen Transformations of LipidPoint 1–Diet Can Change BH

Linoleic Acid (cis–9, cis–12 C18:2)

Conjugated Linoleic Acid(cis–9, trans–11 CLA)

trans–11 C18:1

Stearic (C18:0)

Conjugated Linoleic Acid Isomers

trans–C18:1 Isomers

Stearic (C18:0)

Altered Pathways

Rumen Transformations of LipidPoint 2

MINOR intermediates of biohydrogenation can have MAJOR effects on animal performance and human health

Rumen Transformations of LipidImpact of Rumen Lipid Metabolism

Affects human health Meat and milk higher in saturated fat Bioactive metabolites

Anti-carcinogenic Anti-atherogenic Enhance immune system

Rumen Transformations of LipidImpact of Rumen Lipid Metabolism

Affects animal performance Supply of essential fatty acids– reproduction Fatty acid antimicrobial effects– production Bioactive metabolites

Milk fat depression

Rumen Transformations of LipidQuestion

Match each of the below from the list of answers shown on the right. One answer per blank.

1. ___ Abbreviation of the major fatty acid consumed by dairy cows

2. ___ Increases FFA in rumen contents

3. ___ Abbreviation of the CLA normally produced in the rumen

4. ___ Greatly reduces the supply of essential fatty acids to body tissues

A.BiohydrogenationB.cis–9, trans–11 18:2C.LipolysisD.cis–9, cis–12 18:2E. trans–11 C18:1F. Peroxidation

Rumen Transformations of LipidQuestion

Which of the below is the best substrate for the synthesis of CLA in the rumen?A. Omega–9 fatty acidsB. Essential fatty acidsC. Saturated fatty acidsD. None of the above

Rumen Transformations of LipidQuestions & Answers

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