Chikunya S, Demirel G, Enser M, Wood J D, Wilkinson R G, Sinclair L A
ASRC, Harper Adams University College, School of Agriculture, Edgmond, Newport, Shropshire TF10 8NB, UK.
Br J Nutr. 2004 Apr;91(4):539-50. doi: 10.1079/BJN20031078.
The present study investigated the susceptibility of dietary n-3 PUFA to ruminal biohydrogenation, the stability of ingested vitamin E in the rumen and the subsequent uptake of PUFA and vitamin E into plasma. Six cannulated sheep were assigned to six diets over five 33 d periods, in an incomplete 6x5 Latin square. The diets, based on dried grass, were formulated to supply 50 g fatty acids/kg DM using three lipid sources: Megalac (calcium soap of palm fatty acid distillate; Volac Ltd, Royston, Herts., UK), linseed (formaldehyde-treated; Trouw Nutrition, Northwich, Ches., UK) and linseed-fish oil (formaldehyde-treated linseed+fish oil). The diets were supplemented with 100 or 500 mg alpha-tocopheryl acetate/kg DM. Fat source or level of vitamin E in the diet did not alter microbial activity in the rumen. Biohydrogenation of linoleic acid (18 : 3n-6; 85-90 %), linolenic acid (18 : 3n-3; 88-93 %), docosahexaenoic acid (22 : 6n-3; 91 %) and EPA (20 : 5n-3; 92 %) was extensive. Feeding formaldehyde-treated linseed elevated concentrations of 18 : 3n-3 in plasma, whilst 22 : 6n-3 and 20 : 5n-3 were only increased by feeding the linseed-fish oil blend. Duodenal recovery of ingested vitamin E was high (range 0.79-0.92 mg/mg fed). High dietary vitamin E was associated with increased plasma alpha-tocopherol (2.57 v. 1.46 microg/ml for 500 and 100 mg alpha-tocopheryl acetate/kg DM respectively), although all concentrations were low. Plasma vitamin E levels, however, tended to decrease as the type and quantity of PUFA in the diet increased. The present study illustrates that nutritionally beneficial PUFA in both fish and linseed oils are highly susceptible to biohydrogenation in the rumen. Although alpha-tocopheryl acetate resisted degradation in the rumen, plasma vitamin E status remained deficient to borderline, suggesting either that uptake may have been impaired or metabolism post-absorption increased.
本研究调查了日粮中n-3多不饱和脂肪酸（PUFA）对瘤胃生物氢化作用的敏感性、摄入的维生素E在瘤胃中的稳定性以及随后PUFA和维生素E在血浆中的摄取情况。在五个33天的时间段内，将六只安装了瘤胃瘘管的绵羊按照不完全6×5拉丁方设计分配到六种日粮中。日粮以干草为基础，使用三种脂质来源配制，以提供50克脂肪酸/千克干物质：Megalac（棕榈脂肪酸蒸馏物的钙皂；英国赫特福德郡罗伊斯顿的Volac有限公司）、亚麻籽（经甲醛处理；英国柴郡诺斯维奇的特鲁威营养公司）和亚麻籽-鱼油（经甲醛处理的亚麻籽+鱼油）。日粮中添加了100或500毫克醋酸α-生育酚/千克干物质。日粮中的脂肪来源或维生素E水平并未改变瘤胃中的微生物活性。亚油酸（18:3n-6；85-90%）、亚麻酸（18:3n-3；88-93%）、二十二碳六烯酸（22:6n-3；91%）和二十碳五烯酸（20:5n-3；92%）的生物氢化作用广泛。饲喂经甲醛处理的亚麻籽可提高血浆中18:3n-3的浓度，而只有饲喂亚麻籽-鱼油混合物才能提高22:6n-3和20:5n-3的浓度。摄入的维生素E在十二指肠中的回收率很高（范围为0.79-0.92毫克/毫克摄入量）。高日粮维生素E与血浆α-生育酚增加有关（分别为500和100毫克醋酸α-生育酚/千克干物质时，血浆α-生育酚浓度为2.57微克/毫升和1.46微克/毫升），尽管所有浓度都很低。然而，随着日粮中PUFA的类型和数量增加，血浆维生素E水平趋于下降。本研究表明，鱼油和亚麻籽油中具有营养益处的PUFA在瘤胃中极易发生生物氢化作用。尽管醋酸α-生育酚在瘤胃中抵抗降解，但血浆维生素E状态仍处于缺乏至临界水平，这表明要么摄取可能受损，要么吸收后代谢增加。
