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
Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, Lacombe, AB, T4L 1W1, Canada.
Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, T1J 4B1, Canada.
Lipids. 2017 Jul;52(7):641-649. doi: 10.1007/s11745-017-4259-9. Epub 2017 May 25.
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.
本研究旨在确定，将亚麻籽和干草按25%和75%（干物质基础）的比例混合作为全混合日粮（TMR）喂给育肥牛，或者按顺序投喂（非TMR），是否会导致牛肉脂肪组织（皮下脂肪与肾周脂肪）中多不饱和脂肪酸（PUFA）及其生物氢化中间体（BHI）的富集情况有所不同。48头安格斯杂交育肥牛（体重325±16千克）按体重分层，分为6个栏圈，并将栏圈随机分为TMR组或非TMR组，自由采食，平均饲喂242天。与TMR组育肥牛相比，非TMR组育肥牛皮下脂肪和肾周脂肪中的α-亚麻酸浓度均增加了18摩尔%（P<0.01）。反式18:1异构体在肾周脂肪中的浓度高于皮下脂肪（14.4对9.5摩尔%；P<0.01），且非TMR组的两个脂肪库中该异构体浓度均增加了10摩尔%（P<0.01）。其他BHI，包括非亚甲基中断的18:2（非典型二烯）、共轭亚油酸和共轭亚麻酸（CLnA），受日粮×组织相互作用的影响（P<0.01）。饲喂非TMR时，两个脂肪库中的CLnA和CLA含量均较高，但日粮对肾周脂肪的影响比对皮下脂肪更显著（P<0.01）。非典型二烯在非TMR组的肾周脂肪中含量最高，在TMR组育肥牛中最低（4.3和3.6摩尔%），皮下脂肪中的含量居中。因此，脂质补充剂的顺序投喂会深刻影响牛肉脂肪中PUFA及其BHI的富集，且其差异富集也取决于脂肪库。
