Departamento de Zootecnia, Universidade Estadual de Maringa, 87020-900 Maringa, PR, Brazil.
J Dairy Sci. 2010 Oct;93(10):4781-90. doi: 10.3168/jds.2010-3219.
Four ruminally fistulated primiparous lactating Holstein cows were assigned to a 4 × 4 Latin square design to determine the effects of the site of administration (rumen or abomasum) of flax oil and flax hulls on diet digestibility and milk fatty acid profile of dairy cows. The treatments were 1) oil and hulls administered in the rumen and abomasal infusion of water (RUM/RUM), 2) oil and hulls infused in the abomasum (ABO/ABO), 3) oil administered in the rumen and hulls infused in the abomasum (RUM/ABO), and 4) oil infused in the abomasum and hulls placed in the rumen (ABO/RUM). Cows on the ABO/ABO and RUM/RUM treatments had the highest and lowest amounts of basal dry matter eaten, respectively. Higher dry matter digestibility was obtained when flax oil bypassed the rumen (ABO/ABO and ABO/RUM) compared with when flax oil was administered directly in the rumen (RUM/ABO and RUM/RUM). Apparent digestibility of ether extract was higher when flax hulls were administered in the rumen (RUM/RUM and ABO/RUM) compared with when flax hulls were infused in the abomasum (ABO/ABO and RUM/ABO). The lowest digestibility of acid detergent fiber and neutral detergent fiber was obtained when both flax products were added in the rumen, which may be attributed to the high amount of oil present in the rumen (7.8% of total dry matter input). The lowest yield of 4% fat-corrected milk was obtained for cows on the RUM/RUM treatment, probably as a result of lower dry matter intake and digestibility of fiber. Milk concentrations of protein, fat, total solids, and lactose were similar among treatments. Administration of oil and hulls in the rumen resulted in the highest concentrations of intermediate products of biohydrogenation and total trans fatty acids in milk fat compared with the other treatments. All ratios of n-6 to n-3 fatty acids in milk fat were lower than the 4 to 1 ratio recommended to improve human health. These results suggest that the presence of both flax oil and flax hulls in the rumen decreases 4% fat-corrected milk yield and digestibility but provides a desirable fatty acid profile of milk to enhance consumers' health.
四头荷斯坦泌乳初产奶牛通过瘤胃四叉瘘管被分配到一个 4×4 拉丁方试验中，以确定亚麻籽油和亚麻壳在瘤胃和皱胃中不同投药部位对奶牛日粮消化率和乳脂肪酸组成的影响。处理方法为 1）油和壳在瘤胃中给药，皱胃中输注水（RUM/RUM）；2）油和壳在皱胃中输注（ABO/ABO）；3）油在瘤胃中给药，壳在皱胃中输注（RUM/ABO）；4）油在皱胃中输注，壳在瘤胃中放置（ABO/RUM）。ABO/ABO 和 RUM/RUM 处理组的奶牛基础干物质采食量最高和最低。与在瘤胃中直接给予亚麻油（RUM/ABO 和 RUM/RUM）相比，当亚麻油绕过瘤胃（ABO/ABO 和 ABO/RUM）时，获得了更高的干物质消化率。当在瘤胃中给予亚麻壳（RUM/RUM 和 ABO/RUM）时，乙醚提取物的表观消化率更高，而当在皱胃中输注亚麻壳（ABO/ABO 和 RUM/ABO）时，消化率较低。当两种亚麻产品都添加到瘤胃中时，酸性洗涤剂纤维和中性洗涤剂纤维的消化率最低，这可能归因于瘤胃中存在大量的油（占总干物质输入量的 7.8%）。RUM/RUM 处理组的奶牛获得的 4%脂肪校正奶产量最低，可能是由于干物质采食量和纤维消化率较低所致。处理组之间的牛奶中蛋白质、脂肪、总固体和乳糖的浓度相似。与其他处理相比，油和壳在瘤胃中给药导致牛奶脂肪中生物氢化的中间产物和总反式脂肪酸的浓度最高。牛奶脂肪中 n-6 与 n-3 脂肪酸的所有比值均低于推荐改善人类健康的 4 比 1 比值。这些结果表明，亚麻油和亚麻壳同时存在于瘤胃中会降低 4%脂肪校正奶产量和消化率，但提供了一种理想的牛奶脂肪酸组成，以提高消费者的健康水平。
