Table 1.

The effect of HGT on digestive enzyme activity in duodenum of broilers.¹

Items	HGT, mg/kg				SEM	P value
	0	150	300	450		ANOVA	Linear	Quadratic
21 d of age
α-Amylase, U/g prot	79.88	78.07	60.34	74.37	4.365	0.388	0.466	0.303
Lipase, U/g prot	0.554b	1.955a	0.629b	0.677b	0.198	0.023	0.299	0.102
63 d of age
α-Amylase, U/g prot	48.98	56.67	55.90	56.76	3.616	0.870	0.522	0.664
Lipase, U/g prot	1.088	1.243	1.193	1.821	0.161	0.390	0.154	0.463

¹Values are means of 6 replicates per treatment with 1 bird each.

^a–bMeans in the same row without the same superscript differ significantly (P < 0.05).