Comparison of ferric oxide and ytterbium chloride as digesta markers in broiler chicks

The capacity of Fe2O3 to mimic initial and 5-hr postdose digesta flow rate was evaluated by comparison with Yb-labeled soybean meal in 5-week-old chicks. First visually apparent Fe2O3 corresponded identically with first chemically detectable Fe and Yb. Five-hr marker excretions as a percent of that originally dosed were similar (P greater than .4) for the two markers. Data indicate that first visual appearance of Fe2O3 is sufficient to estimate initial digesta passage rate and that Fe2O3 and Yb-labeled soybean meal have similar flow rates. Because Yb-labeled soybean meal flows with the digesta particulate phase, data also indicate that either Fe2O3 flows with the particulate phase or that broiler digesta liquid and particulate passage rates are similar.