ABSTRACT This study was designed to determine the rumen outflow of fatty acids (FA) and biohydrogenation (BH) extent using alternative sampling sites (reticulum and omasum) to abomasum in dry cows fed different sources of FA. Four Holstein non-pregnant dry cows (≥3 parturitions, and 712 ± 125 kg BW), cannulated in the rumen and abomasum, were randomly assigned to a 4 × 4 Latin square design experiment, containing the following treatments: 1) control (CON); 2) soya bean oil (SO), dietary inclusion at 30 g/kg; 3) whole raw soya beans (WS), dietary inclusion at 160 g/kg; and 4) calcium salts of FA (CSFA), dietary inclusion at 32 g/kg. Rumen outflow of nutrients was estimated using the three markers reconstitution system (cobalt-EDTA, ytterbium chloride, and indigestible neutral detergent fibre [NDF]). Diets with FA sources decreased feed intake and increased FA intake. No differences in nutrient intake and digestibility were detected among cows fed diets supplemented with different FA sources. Diets with FA sources reduced the rumen outflow of DM and NDF, hence decreasing their passage rates. In addition, SO diet reduced the ruminal outflow of DM and NDF in comparison with WS and CSFA. Omasal sampling yielded the highest values of rumen outflow of NDF and potentially degradable NDF (pdNDF), whereas the reticular and abomasal samplings yielded intermediate and least values, respectively. The interaction effect between diet and sampling site was observed for rumen outflow of majority FA (except for C16:0, C18:0, and C18:2 trans-10, cis-12) and BH extension of C18:1 cis, C18:2, and C18:3. Calculations derived from abomasal sampling revealed that WS and CSFA diets had lower BH extent of C18:1 cis and C18:2 in comparison with SO, whereas cows fed CSFA had greater BH extent of C18:3 and lower BH extent of C18:1 cis compared to those fed WS. However, the latter results were not similar when calculations were performed based on the reticular and omasal samplings. Thus, there is evidence that neither reticular nor omasal samplings are suitable for estimating rumen outflow of FA in dry cows. In addition, WS and CSFA diets can increase the abomasal flow of polyunsaturated FA in dry cows.

中文翻译：

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饲喂不同亚油酸来源的干奶牛的瘤胃脂肪酸流出：网状和胃作为真胃的替代采样点

摘要 本研究旨在确定饲喂不同 FA 来源的干奶牛的真胃的替代采样点（网状和瓣口），以确定瘤胃中脂肪酸 (FA) 的流出和生物氢化 (BH) 的程度。四头荷斯坦奶牛（≥ 3 次分娩，712 ± 125 kg BW），在瘤胃和真胃中插管，随机分配到 4 × 4 拉丁方设计实验，包含以下处理：1）对照（CON ); 2) 大豆油 (SO)，膳食添加量为 30 g/kg；3) 整个生大豆 (WS)，膳食添加量为 160 g/kg；和 4) FA 的钙盐 (CSFA)，饮食中包含 32 g/kg。使用三种标记物重建系统（钴-EDTA、氯化镱和难消化的中性洗涤纤维 [NDF]）估计瘤胃营养物质的流出。含 FA 来源的日粮减少了采食量并增加了 FA 摄入量。在饲喂添加不同 FA 来源的日粮的奶牛中，未检测到营养摄入和消化率存在差异。含 FA 来源的日粮减少了瘤胃中 DM 和 NDF 的流出，从而降低了它们的通过率。此外，与 WS 和 CSFA 相比，SO 饮食减少了瘤胃中 DM 和 NDF 的流出。Omasal 采样产生了瘤胃流出的 NDF 和潜在可降解 NDF (pdNDF) 的最高值，而网状和皱胃采样分别产生了中间值和最小值。对于大多数 FA（C16:0、C18:0 和 C18:2 trans-10、cis-12 除外）的瘤胃流出和 C18:1 cis、C18 的 BH 延伸，观察到饮食和采样部位之间的相互作用： 2 和 C18:3。来自皱胃取样的计算表明，与 SO 相比，WS 和 CSFA 日粮的 C18:1 顺式和 C18:2 的 BH 范围较低，而饲喂 CSFA 的奶牛的 C18:3 的 BH 范围更大，而 C18:1 顺式的 BH 范围较低与那些喂食 WS 的人相比。然而，当基于网状和 omasal 采样进行计算时，后者的结果并不相似。因此，有证据表明网状取样和团样取样都不适合估计干奶牛瘤胃 FA 的流出量。此外，WS 和CSFA 日粮可以增加干奶牛多不饱和脂肪酸的皱胃流量。当基于网状和团状采样进行计算时，后者的结果并不相似。因此，有证据表明网状取样和团样取样都不适合估计干奶牛瘤胃 FA 的流出量。此外，WS 和CSFA 日粮可以增加干奶牛多不饱和脂肪酸的皱胃流量。当基于网状和团状采样进行计算时，后者的结果并不相似。因此，有证据表明网状取样和团样取样都不适合估计干奶牛瘤胃 FA 的流出量。此外，WS 和CSFA 日粮可以增加干奶牛多不饱和脂肪酸的皱胃流量。