Food withdrawal is usually used for accurate feed metabolizable energy (ME) assessment in poultry, but its effects on intestinal structure and the absorption of nutrients are unclear. In this study, broilers were fed ad libitum (CT) or withdrew food for 12 (FH12), 24 (FH24), 36 (FH36), or 48 hours (FH48). We showed that food withdrawal increased the energy assimilation when compared with the CT. Food withdrawal improved the digestibility of ether extract and the level of lipid substances and fatty acid‐derived β‐hydroxybutyrate in serum. Compared to the CT, food withdrawal did not influence the digestibility of starch. Due to 12 hours or longer food withdrawal duration increased glutamate oxidation and uric acid excretion, the analyzed digestibility of crude protein was underestimated, although the upregulated amino acid transporter genes. In addition, histological analysis showed that short‐term food withdrawal (12 hours) increased intestinal villus height, crypt depth, and proliferative cell, whereas prolonged food withdrawal (more than 24 hours) impaired villus structure due to the decreased cell proliferation. Moreover, proteomics analysis revealed upregulated pathways in birds withdrawn food for 36 hours involved in nutrient absorption and amino acid oxidation. In conclusion, food withdrawal changes nutrient absorption and utilization, especially for amino acid and ether extract, and results in increased ME. Both glutamate oxidation and fatty acid incomplete oxidation are involved in energy supply after refeeding. In contrast to short‐term food withdrawal, prolonged food withdrawal impairs the intestinal structure and villus renewal. Our findings deserve attention from nutritionists who are analyzing food digestibility.

中文翻译：

---

停食时间影响肉鸡肠道结构、营养吸收和利用

断食通常用于准确评估家禽的饲料代谢能 (ME)，但其对肠道结构和营养吸收的影响尚不清楚。在本研究中，肉鸡在 12 小时 (FH12)、24 小时 (FH24)、36 小时 (FH36) 或 48 小时 (FH48) 期间随意饲喂 (CT) 或断食。我们发现与 CT 相比，食物戒断增加了能量同化。禁食提高了乙醚提取物的消化率以及血清中脂质物质和脂肪酸衍生的 β-羟基丁酸的水平。与 CT 相比，食物戒断不影响淀粉的消化率。由于 12 小时或更长时间的食物戒断持续时间增加谷氨酸氧化和尿酸排泄，粗蛋白的分析消化率被低估，尽管氨基酸转运蛋白基因上调。此外，组织学分析表明，短期禁食（12 小时）会增加肠绒毛高度、隐窝深度和增殖细胞，而长期禁食（超过 24 小时）会由于细胞增殖减少而损害绒毛结构。此外，蛋白质组学分析显示鸟类在 36 小时内撤回食物中涉及营养吸收和氨基酸氧化的通路上调。总之，食物戒断会改变营养吸收和利用，尤其是氨基酸和醚提取物，并导致 ME 增加。谷氨酸氧化和脂肪酸不完全氧化都参与了再喂养后的能量供应。与短期断食相反，长期断食会损害肠道结构和绒毛更新。