Table 8. Effect of combined supplementation of catechin and vitamin C supplementation on rectal temperature (°C) and respiration rate (breaths/min) of broilers during high temperature (days 21-35)

Vitamin C (mg/kg)	0			250			SEM	P-value¹
Catechin (mg/kg)	0	600	1,200	0	600	1,200	SEM	C	V	C × V
Rectal temperature (°C)
d 21	40.63	40.52	40.48	40.50	40.33	40.73	0.04	0.262	0.849	0.125
d 24	41.69	41.63	41.75	41.78	41.68	41.43	0.04	0.166	0.493	0.155
d 28	42.31^a	41.66^b	42.10^ab	41.89^ab	41.98^ab	42.15^ab	0.05	0.018	0.345	0.116
d 35	42.17	42.15	42.21	42.11	42.15	42.18	0.04	0.940	0.397	0.959
Respiration rate (breaths/min)
d 21	61.83	62.25	61.17	60.83	59.95	62.67	0.61	0.853	0.621	0.313
d 24	137.00	129.92	121.00	128.58	126.50	128.40	2.74	0.503	0.792	0.510
d 28	232.83^a	202.17^b	218.50^ab	201.17^b	217.00^ab	221.33^a	2.72	0.007	0.373	0.015
d 35	254.50^a	234.33^b	235.67^b	225.33^b	229.17^b	234.60^b	2.56	0.030	0.004	0.178

Means in same rows with different superscripts are significantly different (P<0.05).
C, catechin; V, vitamin C; C × V, catechin × vitamin C.
SEM, standard error of means.