Supplementary Figure S1 - Timeline experimental protocol - JDS19932

Supplementary Figure S1. Timeline of the experimental protocol per batch of calves (2 batches, 24 calves each). For each treatment (6 calves per treatment), the adaptation period ranged from 6 to 9 weeks for pair 1 to 3 (i.e., paired according to BW). The second batch of calves had a higher BW from the start, therefore having a shorter adaptation period ranging from 5 to 8 weeks. The adaptation period was followed by 7 days in climate respiration chambers (pair-housed) to measure the recovery of 13C tracers in breath after intravenous administration of [13C]sodium bicarbonate and oral administration of [1-13C]octanoate and bacterial protein, as detailed for pair 1. Subsequently, calves were fitted with harnesses to which plastic bags were attached and housed individually in a pen for 7 days, to determine the fecal excretion curves of 3 orally administrated indigestible markers (i.e., Cr-NDF, Yb2O3, and Co-EDTA), as detailed for pair 3.

补充图S1：每批犊牛的实验方案时间线（共设2批，每批24头犊牛）。针对第1至3配对组（即按体重（Body Weight）进行配对的组），每个处理组（每组6头犊牛）的适应期为6至9周。第二批犊牛初始体重更高，因此适应期更短，为5至8周。适应期结束后，犊牛于成对饲养的气候呼吸代谢舱中安置7天，以测定经静脉注射[13C]碳酸氢钠（[13C]sodium bicarbonate）、口服[1-13C]辛酸（[1-13C]octanoate）与菌体蛋白后，呼出气中13C示踪剂的回收率，具体操作细节如第1配对组所述。随后，为犊牛佩戴附有塑料袋的背带，并将其单栏饲养于圈舍中7天，以测定3种口服不可消化标记物（即Cr-NDF、三氧化二镱（Yb₂O₃）、Co-EDTA）的粪便排泄曲线，具体操作细节如第3配对组所述。