Sequential Feeding of Lipid Supplement Enriches Beef Adipose Tissues with 18:3n-3 Biohydrogenation Intermediates
Vahmani, P., Aalhus, J.L., Rolland, D.C., McAllister, T.A., Prieto, N., Block, H.C., Proctor, S.D., Guan, L.L., Dugan, M.E.R. (2017). Sequential Feeding of Lipid Supplement Enriches Beef Adipose Tissues with 18:3n-3 Biohydrogenation Intermediates. Lipids, [online] 52(7), 641-649. http://dx.doi.org/10.1007/s11745-017-4259-9
Plain language summary
The present study was designed to determine if feeding steers extruded flaxseed and hay mixed together or feeding flaxseed before hay would result in different enrichments of polyunsaturated fatty acids and their biohydrogenation intermediates in beef adipose tissues. Forty-eight Angus cross steers were housed in 6 pens, with 3 pens fed per diet for 242 days. The concentrations of α-linolenic acid increased by 18% in adipose tissues when feeding flaxseed before hay. Trans fatty acids increased by 10% in adipose tissues when feeding flaxseed before hay. The conjugated linolenic and conjugated linoleic acids were also higher when feeding flaxseed before hay, but the effect of diet was more pronounced in kidney fat than backfat. Feeding flaxseed before hay can, therefore, profoundly affect the enrichment of polyunsaturated fatty acids and their biohydrogenation intermediates, and their enrichments are also dependant on fat location.
The present study was designed to determine if feeding steers extruded flaxseed and hay (25 and 75%; DM basis) together as a total mixed ration (TMR), or sequentially (non-TMR) would result in different enrichments of polyunsaturated fatty acids (PUFA) and their biohydrogenation intermediates (BHI) in beef adipose tissues [subcutaneous (SC) vs perirenal (PR) fat]. Forty-eight Angus cross steers (325 ± 16 kg) were stratified by weight to six pens, and pens were randomized to either TMR or non-TMR and fed ad libitum for an average of 242 days. The concentrations of α-linolenic acid increased by 18 mol% in both SC and PR in non-TMR steers compared to TMR steers (P < 0.01). trans 18:1 isomers were more concentrated in PR than SC (14.4 vs 9.5 mol%; P < 0.01) and increased by 10 mol% in both fat depots for non-TMR (P < 0.01). Other BHI including non-methylene-interrupted 18:2 (atypical dienes), conjugated linoleic acids and conjugated linolenic acids (CLnA) were affected by diet × tissue interactions (P < 0.01). The CLnA and CLA contents were higher in both fat depots when feeding the non-TMR, but the effect of diet was more pronounced in PR than in SC (P < 0.01). Atypical dienes were highest in PR from non-TMR and lowest in TMR fed steers (4.3 and 3.6 mol%) with SC contents being intermediate. The sequential feeding of lipid supplement can thus profoundly affect the enrichment of PUFA and their BHI in beef fat and their differentially enrichment is also fat depot dependant.