Vanderghinste Paulien, Bautil An, Bedford Michael R, González-Ortiz Gemma, Lamberigts Chris, Aslam Imran, Roeffaers Maarten, Courtin Christophe M
Laboratory of Food Chemistry and Biochemistry & Leuven Food Science and Nutrition Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), KU Leuven, 3001, Leuven, Belgium.
AB Vista, Marlborough, Wiltshire, SN8 4AN, United Kingdom.
Anim Nutr. 2025 Jan 16;21:37-48. doi: 10.1016/j.aninu.2024.12.004. eCollection 2025 Jun.
A promising strategy to support broiler health and performance in a sustainable way is the enhancement of microbial fibre fermentation in broilers. This fermentation mainly occurs in the caeca, but the actual particle size range that allows caecal influx has not yet been described. This study aimed to understand the physical limitations of caecal influx as a function of broiler age by using both solid and soluble markers. In the first trial, the caecal filter mechanism was studied by microscopically visualising the caecal entrance and measuring caecal lobe development and digesta particle size as a function of age (d 8-36) for 44 broilers (Ross 308) receiving a conventional wheat-based diet. In two consecutive trials, microcrystalline cellulose beads (100-700 μm) and a combination of fluorescent polystyrene beads (5-30 μm) and chromium-ethylenediamine tetraacetic acid (Cr-EDTA) were administered to 176 and 189 broilers, respectively, at different ages (d 8-36). Results showed that the actual caecal entrance diameter is significantly reduced due to a dense villi network acting as a filter for digesta inflow. This explains the size gap between the average digesta particle size (D50) of the ileum (451-322 μm) and caeca (5-19 μm), and the outer diameter of the caecal entrance (2000-4000 μm) on d 8 to 36. In contrast to the caecal D50, cellulose beads of 700 μm already entered the caeca at 8 d of age, even though the general caecal influx of digesta particles larger than 100 μm seemed very limited. The caecal influx of the markers further exhibited large individual variation among birds. A maximum of 13.2% (d 9) and 4.3% (d 29) of the total administered soluble marker (Cr-EDTA) was detected in the caeca, 5 h after bolus administration. Both solid and soluble markers showed a larger concentration in the caeca at a young age compared to older ages ( < 0.01), possibly related to the limited caecal functioning early in life. These findings highlight the importance of carefully selecting the physical properties of fibres to be added as a function of age to further improve caecal fibre fermentation in broilers.
以可持续方式支持肉鸡健康和性能的一种有前景的策略是增强肉鸡体内的微生物纤维发酵。这种发酵主要发生在盲肠，但尚未描述允许盲肠吸收的实际颗粒大小范围。本研究旨在通过使用固体和可溶性标记物来了解盲肠吸收的物理限制与肉鸡年龄的关系。在第一个试验中，通过显微镜观察盲肠入口、测量盲肠叶发育以及作为年龄（8 - 36日龄）函数的消化物颗粒大小，对44只接受传统小麦型日粮的罗斯308肉鸡的盲肠过滤机制进行了研究。在两个连续的试验中，分别给176只和189只不同年龄（8 - 36日龄）的肉鸡投喂微晶纤维素珠（100 - 700μm）以及荧光聚苯乙烯珠（5 - 30μm）和铬 - 乙二胺四乙酸（Cr - EDTA）的组合。结果表明，由于密集的绒毛网络对消化物流入起到过滤作用，实际盲肠入口直径显著减小。这解释了回肠平均消化物颗粒大小（D50）（451 - 322μm）与盲肠（5 - 19μm）以及8至36日龄时盲肠入口外径（2000 - 4000μm）之间的大小差距。与盲肠D50不同，700μm的纤维素珠在8日龄时就已进入盲肠，尽管大于100μm的消化物颗粒的总体盲肠吸收似乎非常有限。标记物的盲肠吸收在鸡只之间还表现出很大的个体差异。在推注给药5小时后，盲肠中检测到的可溶性标记物（Cr - EDTA）总量最多为13.2%（9日龄）和4.3%（29日龄）。与老龄相比，固体和可溶性标记物在幼龄时在盲肠中的浓度更高（P < 0.01），这可能与生命早期盲肠功能有限有关。这些发现突出了根据年龄仔细选择添加纤维的物理性质以进一步改善肉鸡盲肠纤维发酵的重要性。
