Manipulating lamb conjugated linoleic acid content and stearoyl coenzyme A desaturase mRNA by either a grass or concentrate feeding regime

Conjugated Linoleic Acid (CLA) is a mixture of isomers of linoleic acid implicated with numerous health promoting properties. These include anti-carcinogenicity (cis-9,trans-11 isomer), anti-atherogenicity and increasing the lean:fat ratio (trans-10,cis-12 isomer). CLA is produced naturally by all ruminant animals through the incomplete biohydrogenation of linoleic acid within the rumen. Alternatively, it can be made endogenously by stearoyl coenzyme A desaturase (SCD) from vaccenic acid (VA) (Griinariet al,2000). It has been well documented that cows fed on a grass diet produce morecis-9,trans-11 in milk than those fed on a concentrate based regime (Kellyet al,1998) but to date, little work would appear to have been undertaken to determine if this is the case with sheep tissues. In the present study, a grass based diet was compared with a concentrate diet in order to determine whether the CLA content of adipose tissue differed and if so, which isomer and what mechanisms may be involved.