This study was conducted to evaluate the effects of dietary free fatty acid (FFA) content and degree of fat saturation on production performance, lipid and calcium digestibility, and intestinal function of laying hens. For a 15-week period, a total of 144 laying hens (19 weeks old) were randomly assigned to 8 dietary treatments, which were obtained by gradually replacing crude soybean oil with soybean acid oil (AO), or crude palm oil with palm fatty acid distillate (FAD). Thus, there were 4 soybean and 4 palm diets with 6% added fat varying in their FFA percentage (10%, 20%, 30%, and 45%), following a 2 × 4 factorial design. Each treatment included 6 replicates with 3 birds per replicate. Average daily feed intake and final body weight were significantly higher in palm diets (P < 0.001), while no differences were found in egg mass and feed conversion ratio. Higher levels of FFA in soybean diets resulted in lower egg production and higher egg weight (linear, P < 0.01). Regarding the degree of fat saturation, hens fed soybean diets presented higher digestibility of ether extract (EE), fatty acids, and calcium than palm diets (P < 0.001). The dietary FFA percentage negatively affected the digestibility of EE and calcium (P < 0.01), while having little effect on FA digestibility. There was a significant interaction in the AME; lower values were reported in soybean diets as the dietary FFA percentage increased (linear, P < 0.01), whereas palm diets remained unaffected. The experimental diets had little effect on gastrointestinal weight and length. However, the jejunum of soybean diets showed higher villus height and higher villus height-to-crypt depth ratio than palm diets (P < 0.05), and the dietary FFA percentage increased the crypt depth and decreased the villus height-to-crypt depth ratio (linear, P < 0.05). It was concluded that varying dietary FFA content did not affect fat utilization as much as the degree of saturation did, supporting the use of AO and FAD as alternative fat ingredients.

本研究旨在评估日粮游离脂肪酸 (FFA) 含量和脂肪饱和度对蛋鸡生产性能、脂质和钙消化率以及肠道功能的影响。在为期 15 周的时间里，共有 144 只蛋鸡（19 周龄）被随机分配到 8 个日粮处理组，这些日粮处理是通过逐渐用大豆酸油 (AO) 代替毛豆油，或用棕榈脂肪逐渐代替毛棕榈油而获得的酸馏出物 (FAD)。因此，按照 2 × 4 析因设计，有 4 种大豆和 4 种棕榈日粮添加了 6% 的脂肪，FFA 百分比不同（10%、20%、30% 和 45%）。每个处理包括 6 个重复，每个重复 3 只鸡。棕榈日粮的平均每日采食量和最终体重显着更高（P < 0.001)，而蛋重和饲料转化率没有差异。大豆日粮中较高水平的游离脂肪酸会导致较低的产蛋量和较高的蛋重（线性，P  < 0.01）。关于脂肪饱和度，饲喂大豆日粮的母鸡对醚提取物 (EE)、脂肪酸和钙的消化率高于棕榈日粮 ( P  < 0.001)。日粮 FFA 百分比对 EE 和钙的消化率有负面影响（P  < 0.01），而对 FA 消化率的影响很小。AME 中有显着的交互作用；随着膳食 FFA 百分比的增加，大豆膳食中报告的值较低（线性，P < 0.01)，而棕榈饮食不受影响。实验饮食对胃肠重量和长度几乎没有影响。然而，大豆日粮的空肠绒毛高度和绒毛高度与隐窝深度比值均高于棕榈日粮（P  < 0.05），日粮FFA百分比增加了隐窝深度并降低了绒毛高度与隐窝深度比（线性，P  < 0.05）。得出的结论是，不同的日粮 FFA 含量对脂肪利用的影响不如饱和度那么大，这支持使用 AO 和 FAD 作为替代脂肪成分。