Australian Research Council, Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, 4072, Australia.
Food Funct. 2019 Dec 11;10(12):8298-8308. doi: 10.1039/c8fo02496k.
Undigested nutrients and fermentable fibre in the distal ileum and colon stimulate intestinal brakes, which reduce gastric-emptying and digesta-passage-rate, and subsequently limit feed/food-intake. Fibre can also stimulate passage rate potentially increasing feed intake (FI). In order to experimentally determine the relationships between these two hypothesised actions of fibre, five levels of wheat-bran (WB) or oat-hulls (OH) were added to a highly digestible starch-based diet fed to pigs ad-libitum for three weeks. Average-daily-feed-intake (ADFI), faecal short-chain-fatty-acids (SCFA) and related parameters were determined at 7, 14 and 21d. A linear mixed model was fitted to FI and fermentation parameters. Overall, WB diets showed 8-11% lower ADFI (7-14d: p < 0.05; 7-21 & 0-21d: p = 0.053) than OH diets. WB diets produced over 20% more (21d: p < 0.01) SCFA than OH or Control diets. WB at 25% produced 22% more (7d: p < 0.05) SCFA than any other diet. Diets with WB at 25 and 35%, showed higher hydration capacity than any other diet (p < 0.001). OH at 10% had an unusually low FI and a markedly higher hydration capacity. With increasing levels of OH, intake of base diet was 7% more than control at 5% OH, but 8% less than control at 20% OH. With increasing WB content, intake of base diet decreased. From these results, we propose that three mechanisms control the effects of fibre on FI: initial increase in passage rate and feed intake at low concentrations of non-swelling fibres; a depression in FI from high fibre bulk; and reduced feed intake from stimulation of ileal and colonic brakes.
未消化的营养物质和可发酵纤维在回肠末端和结肠中刺激肠道制动，从而减缓胃排空和食糜通过速度，进而限制采食量。纤维还可以刺激通过速度，从而潜在增加采食量（FI）。为了在实验中确定纤维的这两种假设作用之间的关系，将 5 个水平的麦麸（WB）或燕麦壳（OH）添加到自由采食的猪高易消化淀粉基础日粮中，持续 3 周。在第 7、14 和 21 天测定平均日采食量（ADFI）、粪便短链脂肪酸（SCFA）和相关参数。采用线性混合模型拟合 FI 和发酵参数。总的来说，WB 日粮的 ADFI 比 OH 日粮低 8-11%（第 7-14 天：p<0.05；第 7-21 天和第 0-21 天：p=0.053）。WB 日粮比 OH 或对照日粮产生超过 20%的更多 SCFA（第 21 天：p<0.01）。25%的 WB 日粮比任何其他日粮产生多 22%（第 7 天：p<0.05）的 SCFA。含有 25%和 35%WB 的日粮比任何其他日粮具有更高的水合能力（p<0.001）。10%的 OH 日粮具有异常低的 FI 和明显更高的水合能力。随着 OH 水平的增加，与对照日粮相比，5%OH 组的基础日粮采食量增加了 7%，而 20%OH 组的基础日粮采食量减少了 8%。随着 WB 含量的增加，基础日粮的采食量减少。根据这些结果，我们提出三个机制来控制纤维对 FI 的影响：低浓度非膨胀纤维初始增加通过速度和饲料摄入量；高纤维容积引起的 FI 降低；以及回肠和结肠制动刺激导致采食量减少。
