The effect of whole linseed or xylose treated whole linseed on dairy cow performance and level of the fatty acids C_18:3, C_20:5and C_22:6in milk fat

Abstract

The Committee on Medical Aspects of Food Policy report Nutritional Aspects of Cardiovascular Disease recommended increased dietary intakes of the long chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid to help protect against cardiovascular disease. There is some evidence that a-linolenic acid can be elongated and desaturated by mammalian enzyme systems to produce small amounts of eicosapentaenoic and docosahexaenoic acids. Whole linseeds are rich in a–linolenic acid, and it has been suggested that feeding this oilseed to dairy cows may result in higher levels of the long chain polyunsaturated fatty acids in bovine milk. To examine this hypothesis, the effect of feeding whole ground linseed and xylose treated whole ground linseed on the performance and milk composition of dairy cows was investigated.Either form of whole linseed reduced dry matter intakes and milk protein concentration. The xylose treated whole linseed increased milk yield, but neither linseed source changed milk fat concentration. Levels of milk a-linolenic acid increased to 1.2 g/100 g fatty acid when whole ground linseed was fed, and to 1.5 g/100 g fatty acid with the xylose treated linseed compared with 0.7 g/100 g fatty acid for cows fed the control diet. The efficiency of incorporation of additional dietary a-linolenic acid into milk fat was estimated to be 1.6 and 3.4% for the whole ground and xylose treated whole ground linseed respectively. Feeding whole ground linseed increased the proportion of a-linolenic acid in milk fat, but there was no evidence of eicosapentaenoic and docosahexaenoic acids in milk fat, suggesting that if any elongation and desaturation of a-linolenic acid occurs in dairy cows, none is transferred to milk.

Long-Chain Fatty Acid Metabolism in Dairy Cows: A Meta-Analysis of Milk Fatty Acid Yield in Relation to Duodenal Flows and De Novo Synthesis

“…[1]), under this hypothesis, could be partly explained by the decrease in C4 to C16 yield. Indeed, when lipid supplementation does not induce a decrease in de novo synthesis (e.g., protected lipid sources), there are high increases in milk C18 yield (Bartsch et al, 1976;Goering et al, 1977;Mansbridge et al, 1999;Goodridge et al, 2001).…”

Lipid fraction of creams collected in the Parmigiano‐Reggiano cheese production area in response to extruded linseed supplementation of dairy cows’ diets: GC‐FID and FT‐MIR evaluation

“…Results in this study also showed that the concentration of C18:3n3 in creams from the linseed group increased significantly (P < 0.01), and this may be attributed to the FA composition of linseed because a rich source of C18:3n3. Previous studies about the effect of fat-supplemented rations on FA profile found that linseeds increased the proportion of C18:3n3 up to 1.5% of total FA (Kennelly 1996;Mansbridge et al 1999) and the C18:3n3 content was maximised SFA, sum of all saturated fatty acids; SC-SFA, total short-chain saturated fatty acids (C4-C10); MC-SFA, total medium-chain saturated fatty acids (C12-C16); LC-SFA, total long-chain saturated fatty acids (>C17); UFA, sum of all unsaturated fatty acid; MUFA, sum of all monounsaturated fatty acids; PUFA, sum of all polyunsaturated fatty acids; TFA, sum of total trans-fatty acids; CLA, sum of cis-9, trans-11C18:2 and other CLA isomers; n3-PUFA, sum of all n3 polyunsaturated fatty acids; n6-PUFA, sum of all n6 polyunsaturated fatty acids. Index of D9-desaturase was calculated according to Malau-Aduli et al (1997).…”

“…Previous studies about the effect of fat‐supplemented rations on FA profile found that linseeds increased the proportion of C18:3 n 3 up to 1.5% of total FA (Kennelly ; Mansbridge et al . ) and the C18:3 n 3 content was maximised when cows were fed with full fat linseeds (Secchiari et al . ).…”