Ruminal Synthesis of CLA

The rate of lipolysis is related to melting point seed oils (linseed, soya) palm oil = tallow. Fish oils are hydrolyzed more slowly, probably caused by steric hindrance of the ester bonds (Miller and Cramer, 1969 Palmquist and Kinsey, 1994). Hydrogenated tallow (iodine number 30) lipolysis rate was slow (Palmquist and Kinsey, 1994) or absent (Beam et al., 2000), likely caused by insolubility of the substrate. 

Biosynthesis of CLA by rumen bacteria arises from isomerization of polyunsaturated dietary Cl8 fatty acids CLA and other ethenoic isomers occur as intermediates in the pathways of ruminal BH, whereby the unsaturated 

Ruminal synthesis of trans, trans CLA isomers with double bonds in positions 9, 11 and 10, 12 also are enhanced when diets contain high amounts of concentrates (Piperova et al., 2002) or are supplemented with fish oil (Shingfield et al., 2003). Formation of trans. trans CLA is unexpected 

The reduction of RA to VA is catalyzed by cis-9, tram-11 octadecadienoic acid reductase. Isolation of this membrane-bound enzyme from B. fibrisol-vens indicates that it has an absolute requirement for iron and expresses maximal activity at a pH between 7.2 and 8.2 (Hughes et al., 1982). Pure culture studies with B. fibrisolvens also have shown that the reductase is not 

Hydrogenation (group A, group B) trans-11, c/s-15 Octadecadienoic acid 

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