State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Adisseo Animal Nutrition, Dubai 00000, United Arab Emirates.
Poult Sci. 2022 Jul;101(7):101932. doi: 10.1016/j.psj.2022.101932. Epub 2022 Apr 27.
Fasting is typically used to empty the gastrointestinal tract (GIT) and assess feed metabolizable energy (ME). However, the effects of fasting on energy and nutrient utilization are not well understood. This study aimed to explore the difference in GIT emptying, energy and nutrient utilization of broilers and adult roosters fed corn-soybean meal-based diet upon fasting. In experiment 1, 7 cages of broilers/adult roosters were selected and fasted for 72 h, and excreta were collected from 12 h of fasting and analyzed every 12 h to explore GIT emptying. Results indicated the GIT emptying time of free-feeding broilers or adult roosters is 12 or 24 h, respectively. In experiment 2, 4 treatments were used that consisted of 2 ages of birds (25 d broilers and 30 wk adult roosters) and 2 feeding forms (fed ad libitum or fasted for 36 h before formal feeding). Excreta was collected during refeeding, and the total collection method (TCM) and the index method (IM) were used for data analysis. Compared to non-fasted group, fasting increased the total tract digestibility of ME, gross energy (GE), and ether extract (EE) (by 1.80, 3.50 and 18.56%, respectively, all P < 0.05) in broilers, but decreased the total tract digestibility of nitrogen by 8.10% (P < 0.05). Conversely, fasting increased total tract digestibility of nitrogen in adult roosters (-0.37% vs. 11.65%, P < 0.05). The comparative analysis found that total tract digestibility of nitrogen obtained by TCM was greater than the result calculated by IM (17.76 % vs. -0.37). Similarly, total tract digestibility of GE calculated by TCM was significantly higher than the value observed by IM (P < 0.05). However, the results of total tract digestibility of GE and nitrogen in broilers calculated by TCM were consistent with those obtained by IM. Overall, fasting increases total tract digestibility in broilers and total tract digestibility of nitrogen in adult roosters, respectively. Additionally, total tract digestibility calculated by TCM may be overestimated.
禁食通常用于排空胃肠道 (GIT) 并评估饲料可代谢能 (ME)。然而，禁食对能量和营养素利用的影响尚不清楚。本研究旨在探讨饲喂玉米-豆粕基础日粮时，肉鸡和成年公鸡禁食对 GIT 排空、能量和营养素利用的差异。在试验 1 中，选择 7 个鸡笼/成年公鸡笼进行禁食 72 h，从禁食 12 h 开始收集粪便，每隔 12 h 分析一次，以探索 GIT 排空情况。结果表明，自由采食的肉鸡或成年公鸡的 GIT 排空时间分别为 12 或 24 h。在试验 2 中，采用 2 种鸟类（25 日龄肉鸡和 30 周龄成年公鸡）和 2 种饲养方式（自由采食或禁食 36 h 后正式采食）进行 4 种处理。在重新采食期间收集粪便，并采用全肠道消化率法（TCM）和指数法（IM）进行数据分析。与非禁食组相比，禁食使肉鸡的 ME、总能 (GE) 和乙醚提取物 (EE) 的全肠道消化率分别增加了 1.80%、3.50%和 18.56%（均 P < 0.05），但使氮的全肠道消化率降低了 8.10%（P < 0.05）。相反，禁食使成年公鸡的氮的全肠道消化率增加了 0.37%（与 11.65%相比，P < 0.05）。比较分析发现，TCM 法测定的氮的全肠道消化率大于 IM 法计算的结果（17.76%与-0.37%）。同样，TCM 法测定的 GE 的全肠道消化率显著高于 IM 法观察到的结果（P < 0.05）。然而，TCM 法计算的肉鸡 GE 和氮的全肠道消化率与 IM 法的结果一致。总体而言，禁食分别增加了肉鸡的全肠道消化率和成年公鸡的氮的全肠道消化率。此外，TCM 法计算的全肠道消化率可能被高估。
