An experiment was conducted to 1) compare the regression and fat-free diet methods for estimating total or basal endogenous losses of fat (ELF) and fatty acids (ELFA) and true digestibility (TD) or standardized digestibility (SD) of fat and fatty acids in growing pigs and 2) compare these estimated values at the end of the ileum and over the entire intestinal tract. Ten barrows (initial body weight: 45.1 ± 2.8 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to one of five experimental diets in a three-period Youden Square design. A fat-free diet was formulated using cornstarch, soy protein isolate, and sucrose. Four oil-added diets were formulated by adding four levels of soybean oil (2%, 4%, 6%, and 8%) to the fat-free basal diet at the expense of cornstarch. All diets contained 26% sugar beet pulp and 0.40% chromic oxide. Results indicated that there were no differences between true ileal digestibility (TID) of fat and true total tract digestibility (TTTD) of fat when pigs were fed soybean oil. The TID of C18:0 and total saturated fatty acids (TSFA) was greater than TTTD (P < 0.05). The total ELF at the end of the ileum were not different from that over the entire intestinal tract. In addition, total endogenous losses of C18:0 and TSFA were greater for the entire intestinal tract than at the end of the ileum, whereas total endogenous losses of C18:2 and total unsaturated fatty acids were just the opposite. Similar results were observed for basal ELF and ELFA. As the inclusion level of soybean oil increased, apparent digestibility (AD) of fat and fatty acids increased linearly (P < 0.05) except for apparent ileal digestibility of C18:0. However, SD of fat and fatty acids was not influenced by the inclusion level of soybean oil. Estimation of ELF and ELFA observed by the regression and fat-free diet methods did not differ when measured at the end of the ileal or total tract. There were no differences between the estimations of TD and SD of fat and fatty acids for soybean oil. Collectively, the estimation of TD or SD of fat can be measured over the entire intestinal tract, whereas the ileal analysis method should be used to determine the ELF, ELFA, and TD or SD of fatty acids. Correcting AD for basal ELF and ELFA can accurately estimate SD values of fat and fatty acids.

中文翻译：

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比较回归和无脂肪饮食方法，用于估计生长猪的回肠和全道内源性损失以及脂肪和脂肪酸的消化率

进行了一项实验，以 1) 比较回归和无脂饮食方法，以估计脂肪 ( ELF ) 和脂肪酸 ( ELFA ) 的总或基础内源性损失以及真实消化率 ( TD ) 或标准化消化率 ( SD)。) 生长猪的脂肪和脂肪酸，以及 2) 比较回肠末端和整个肠道的这些估计值。十只手推车（初始体重：45.1 ± 2.8 公斤）在回肠远端通过外科手术安装了 T 型套管，并在三期 Youden Square 设计中分配到五种实验饮食中的一种。使用玉米淀粉、大豆分离蛋白和蔗糖配制无脂肪饮食。通过在无脂基​​础日粮中添加四种水平的大豆油（2%、4%、6% 和 8%），以玉米淀粉为代价，配制了四种添加油的日粮。所有日粮都含有 26% 的甜菜浆和 0.40% 的氧化铬。结果表明，脂肪的真回肠消化率（TID）与真全消化道消化率（TTTD）之间没有差异。) 猪饲喂大豆油时的脂肪含量。C18:0 和总饱和脂肪酸 ( TSFA )的 TID大于 TTTD ( P < 0.05)。回肠末端的总 ELF 与整个肠道的总 ELF 没有区别。此外，整个肠道的 C18:0 和 TSFA 的总内源性损失大于回肠末端，而 C18:2 和总不饱和脂肪酸的总内源性损失正好相反。对于基础 ELF 和 ELFA，观察到类似的结果。随着豆油添加量的增加，脂肪和脂肪酸的表观消化率（AD）线性增加（P< 0.05) 除了 C18:0 的表观回肠消化率。然而，脂肪和脂肪酸的 SD 不受大豆油含量的影响。当在回肠末端或总道末端测量时，通过回归和无脂饮食方法观察到的 ELF 和 ELFA 的估计没有差异。大豆油的脂肪和脂肪酸的 TD 和 SD 估计值之间没有差异。总的来说，可以在整个肠道内测量脂肪的 TD 或 SD，而回肠分析方法应用于确定脂肪酸的 ELF、ELFA 和 TD 或 SD。校正基础 ELF 和 ELFA 的 AD 可以准确估计脂肪和脂肪酸的 SD 值。