Sklan D, Arieli A, Chalupa W, Kronfeld D S
J Dairy Sci. 1985 Jul;68(7):1667-75. doi: 10.3168/jds.S0022-0302(85)81012-2.
Sheep were fed diets containing 7.5% added stearic acid, oleic acid, or tristearin for 21 days. In addition, 50 microCi/kg cerium-141 was included for the last 10 days on experimental diets as an unabsorbed reference substance. In the rumen dietary triglycerides were approximately 50% hydrolyzed, and hydrogenation resulted in saturation of the free fatty acid fraction. Some net synthesis of phospholipids, presumably microbial phospholipids, occurred in the rumen. In the intestine immediately distal to the pylorus, extensive secretion of bile acids, cholesterol, phospholipids, triglycerides, free fatty acids, and lipase occurred. This resulted in doubling of fatty acid fluxes through the duodenum. These endogenous secretions were reabsorbed rapidly however, with the major site of lipid and bile acid absorption in the region .6 to 4 m distal to the pylorus. Additional but less absorption occurred in the more distal segments of the small intestine. Overall absorption of stearic acid, oleic acid, and tristearin supplements was in the range 60 to 70%, and no differences were apparent between fats. Unsaturated fatty acids were over 90% absorbed as compared with 55 to 65% for saturated fatty acids. No significant effect of any of the supplements was observed on ruminal total volatile fatty acids, ratios of volatile fatty acids, or on overall cellulose or caloric digestion.
给绵羊喂食添加了7.5%硬脂酸、油酸或三硬脂酸甘油酯的日粮，持续21天。此外，在实验日粮的最后10天添加50微居里/千克的铈-141作为未吸收的参考物质。瘤胃中日粮甘油三酯约50%被水解，氢化作用导致游离脂肪酸部分饱和。瘤胃中发生了一些磷脂的净合成，推测是微生物磷脂。在紧靠幽门的十二指肠，胆汁酸、胆固醇、磷脂、甘油三酯、游离脂肪酸和脂肪酶大量分泌。这导致通过十二指肠的脂肪酸通量增加了一倍。然而，这些内源性分泌物很快被重新吸收，脂质和胆汁酸的主要吸收部位在距幽门0.6至4米的区域。在小肠更远端的部分也有额外但较少的吸收。硬脂酸、油酸和三硬脂酸甘油酯补充剂的总体吸收率在60%至70%之间，不同脂肪之间没有明显差异。与饱和脂肪酸55%至65%的吸收率相比，不饱和脂肪酸的吸收率超过90%。未观察到任何补充剂对瘤胃总挥发性脂肪酸、挥发性脂肪酸比例或总体纤维素或热量消化有显著影响。
