Table 3.
Effects of heat stress on the level of hypothalamus-pituitary-adrenal (HPA) axis and the guanidinoacetic acid (GAA) intervention effects in broilers.
| Treatment1 |
P value3 |
|||||
|---|---|---|---|---|---|---|
| Items2 | NC | HS | PF | HG | ANOVA | T test |
| Heat exposure for 7 d | ||||||
| CRF (ng/mL) | 63.30 ± 6.42b | 101.77 ± 8.26a | 117.27 ± 7.38a | 114.82 ± 8.28 | <0.001 | 0.661 |
| ACTH (ng/L) | 63.60 ± 10.67 | 43.21 ± 5.05 | 49.00 ± 7.91 | 44.21 ± 10.82 | 0.103 | 0.336 |
| CORT (ng/mL) | 8.19 ± 0.14b | 9.35 ± 0.31a | 8.58 ± 0.24b | 7.83 ± 0.31⁎⁎ | 0.015 | 0.009 |
| Heat exposure for 14 d | ||||||
| CRF (ng/mL) | 107.16 ± 10.83 | 132.32 ± 9.71 | 127.75 ± 11.96 | 167.33 ± 17.30 | 0.139 | 0.456 |
| ACTH (ng/L) | 42.68 ± 1.25 | 37.60 ± 4.91 | 36.87 ± 4.25 | 49.05 ± 4.70 | 0.322 | 0.381 |
| CORT (ng/mL) | 8.52 ± 0.21b | 9.92 ± 0.21a | 8.96 ± 0.32b | 8.01 ± 0.32⁎⁎ | 0.047 | 0.007 |
1
NC, normal control group; HS, heat stress group; PF, pair-fed group; HG, GAA group. Values are mean ± SE of 6 replicates.
2
CRF, corticotropin-releasing factor; ACTH, adrenocorticotropic hormone; CORT, corticosterone.
3
One-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.
ab
Means with different superscripts within each row are significantly different among the NC, HS, and PF groups (P < 0.05).
⁎⁎
Means with asterisks indicate a significant difference between HS and HG group (P < 0.01).