Influence of oilseed supplement ranging in n-6/n-3 ratio on fatty acid composition and δ5-, δ6-desaturase protein expression in steer muscles

Pickova, J.; Turner, T. D.; Mitchell, A.; Duynisveld, J.; Pickiva, J; Doran, O.; McNiven, M. A.

Abstract

This study investigated effects of roasted or extruded oilseed supplementation ranging in n-6/n-3 ratios from 0.3 to 5.0 on the fatty acid composition and expression of delta-5 desaturase (δ5d) and δ6-desaturase (δ6d) protein in commercial steer cheek (m. masseter) and diaphragm (pars costalis diaphragmatis) muscles. In general, the n-6/n-3 ratio of the diet had a subsequent effect on the muscle n-6/n-3 ratio (P < 0.05), with muscle 18:2n-6 and 18:3n-3 content relating to proportion of dietary soya bean and linseed (P < 0.01). Compared with canola, pure linseed and soya bean diets reduced 14:1c-9 and 16:1c-9 (P < 0.05) but increased 18:1t-11 and c-9,t-11 conjugated linoleic acid (CLA) content (P < 0.01). Oilseed processing had a minor influence but extruded oilseeds increase 18:1t-11 and c-9,t-11 CLA compared with roasted (P < 0.05). Polar lipid 18:3n-3 and n-3 long-chain polyunsaturated fatty acid (LC, >20 carbons PUFA) derivative content increased in relation to dietary linseed supplementation in the diaphragm (P < 0.01), whereas only 18:3n-3 was increased in the cheek (P < 0.01). Protein expression did not differ between diets; however, in each muscle the Δ5d protein expression had a stronger association with the desaturase products rather than the precursors. The relationship between δd protein expression and the muscle LC n-6/n-3 ratio was negative in both muscles (P < 0.05). The relationship between δd protein expression and the LC n-6/n-3 ratio was positive in the cheek (P < 0.001) and negative in the diaphragm (P < 0.05). In conclusion, diet n-6/n-3 ratio affected muscle 18:2n-6 and 18:3n-3 deposition, whereas the Δ5d and δd protein expression had some influence on the polar lipid LC-PUFA profile. Results reaffirm that processed oilseeds can be used to increase the proportion of fatty acids potentially beneficial for human health, by influencing the formation of LC-PUFA and reducing the n-6/n-3 ratio. © Copyright © The Animal Consortium 2012.

• Journal Article Type: Article
• Publication Date: Dec 1, 2012
• Journal: Animal
• Print ISSN: 1751-7311
• Electronic ISSN: 1751-732X
• Publisher: Cambridge University Press (CUP)
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Issue: 12
• Pages: 1973-1984
• DOI: https://doi.org/10.1017/S1751731112000985
• Keywords: cattle, muscle, fatty acid composition, lipogenic enzyme, diet
• Public URL: https://uwe-repository.worktribe.com/output/941657
• Publisher URL: http://dx.doi.org/10.1017/S1751731112000985