Table 4.

Effects of heat stress on the immune organ indexes and the guanidinoacetic acid (GAA) intervention effects in broilers.

	Treatment1				P value2
Items	NC	HS	PF	HG	ANOVA	T test
Heat exposure for 7 d
Spleen (g/100 g)	0.13 ± 0.01	0.10 ± 0.01	0.14 ± 0.03	0.10 ± 0.01	0.292	0.195
Thymus (g/100 g)	0.34 ± 0.04a	0.14 ± 0.01b	0.16 ± 0.02b	0.12 ± 0.01	<0.001	0.951
Bursa of Fabricius (g/100 g)	0.08 ± 0.01	0.07 ± 0.01	0.09 ± 0.01	0.07 ± 0.01	0.114	0.306
Heat exposure for 14 d
Spleen (g/100 g)	0.12 ± 0.02	0.10 ± 0.02	0.13 ± 0.01	0.09 ± 0.01	0.579	0.636
Thymus (g/100 g)	0.30 ± 0.04a	0.14 ± 0.02b	0.28 ± 0.03a	0.11 ± 0.03	0.001	0.841
Bursa of Fabricius (g/100 g)	0.06 ± 0.01a	0.04 ± 0.01b	0.06 ± 0.01a	0.06 ± 0.01	0.027	0.084

¹NC, normal control group; HS, heat stress group; PF, pair-fed group; HG, GAA group. Values are mean ± SE of 6 replicates.

²One-way ANOVA and Tukey's test were conducted for the NC, HS, and HG groups; T test was conducted for the HS and HG groups.

^abMeans with different superscripts within each row are significantly different among the NC, HS and PF groups (P < 0.05).