Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Abstract

Thirty lactating dairy cows were used in a 3 3 3 Latin-square design to investigate the effects of a raw or extruded blend of linseed and wheat bran (70:30) on plasma and milk fatty-acids (FA). Linseed diets, containing 16.6% linseed blend on a dry-matter basis, decreased milk yield and protein percentage. They decreased the proportions of FA with less than 18 carbons in plasma and milk and resulted in cis-9, cis-12, cis-15 18:3 proportions that were more than three and four times higher in plasma and milk, respectively, whereas cis-9, cis-12 18:2 proportions were decreased by 10-15%. The cis-9, trans-11, cis-15 18:3 isomer of conjugated linolenic acid was not detected in the milk of control cows, but was over 0.15% of total FA in the milk fat of linseed-supplemented cows. Similarly, linseed increased plasma and milk proportions of all biohydrogenation (BH) intermediates in plasma and milk, including the main isomer of conjugated linoleic acid cis-9, trans-11 18:2, except trans-4 18:1 and cis-11, trans-15 18:2 in plasma lipids. In milk fat, compared with raw linseed, extruded linseed further reduced 6:0-16:0 even-chain FA, did not significantly affect the proportions of 18:0, cis-9 18:1 and cis-9, cis-12 18:2, tended to increase cis-9, cis-12, cis-15 18:3, and resulted in an additional increase in the proportions of most BH intermediates. It was concluded that linseed addition can improve the proportion of conjugated linoleic and linolenic acids, and that extrusion further increases the proportions of intermediates of ruminal BH in milk fat.

Conjugated Linoleic and Linolenic Acid Production by Bacteria: Development of Functional Foods

“…At the present, the effect of diet on CLNA concentration in milk was only reported by one work, where cows not fed with extruded linseed (control) have no CLNA in milk, but linseed supplementation in diet increased both CLA and CLNA content, reaching the latest fatty acid a value of 0.15% of total fatty acids [22]. In this study, CLNA was also present only as c9, t11, c15 isomer.…”

“…All conjugated fatty acids are absorbed by intestine cells, reason why they are further present in milk and meat fat [22][23]. [17]) and endogenous synthesis of CLA in mammary gland (dotted arrow).…”

“…In the last years, different supplements such as vegetal oils, animal fat, natural pasture and seeds were used to improve fatty acid profile of milk, to attempt higher levels of CLA [32][33] or CLNA [22,34].…”

Alimentation des vaches laitières et composition en acides gras du lait

“…L'addition de cette graine, crue ou extrudée, est souvent réalisée lorsqu'un objectif d'enrichissement des produits laitiers en n-3 est poursuivi. L'augmentation de proportion de C18:3n-3 est en moyenne de 0,5% (tableau 1), mais des augmentations allant jusqu'à 1% ont été observées (Akraim et al 2007 ;Lerch et al 2012), ces augmentations étant plus importantes avec des graines extrudées qu'avec des graines crues (Akraim et al 2007). …”

“…L'addition à la ration de graines de lin augmente sensiblement les proportions de la plupart des C18:1 ayant des double-liaisons trans en positions delta 9, 10, 11, 13+14 (très difficiles à séparer analytiquement), 15 ou 16 (Akraim et al 2007 ;Glasser et al 2008a), et l'extrusion des graines augmente cet effet (Akraim et al 2007). Au contraire, lors d'addition de sources de C18:2n-6 comme les graines de soja ou de tournesol, ce sont surtout les proportions de C18:1 trans dont la double liaison est entre les carbones 6 et 11 qui augmentent (Glasser et al 2008a).…”