Table 4.

Digestive lactase activity (U/mg protein) in male Holstein calves fed milk and a starter supplemented with leucine and phenylalanine

Sampling Site (%)	Treatments1				SEM	P-value
	C	P	L	PL		P	L	P × L
0	357.26	400.36	290.15	425.42	54.289	0.425	0.849	0.678
20	343.13	282.20	520.50	669.35	72.513	0.766	0.692	0.480
40	452.93	354.98	448.43	565.68	52.261	0.936	0.399	0.379
60	503.54	637.13	521.53	440.03	83.298	0.878	0.599	0.529
80	301.83	412.11	633.86	368.19	58.658	0.519	0.240	0.131
100	589.58	339.46	458.28	397.50	62.978	0.235	0.775	0.463
Site effect					P=0.728
Interaction between Site and Treatment					P=0.604

¹C, control; P, phenylalanine; L, leucine; PL, leucine plus phenylalanine. The total length of the small intestine from the distal region of the pylorus to the ileal–cecal junction was defined as 100%. The digesta samples at the 0, 20, 40, 60, 80, and 100% relative sites were collected to determine enzyme activities.