Table 4.
Effects of heat stress on the relative length and weight of the small intestine of broilers and guanidinoacetic acid (GAA) intervention effect
| Items | Treatment1 | P-value | ||||
|---|---|---|---|---|---|---|
| NC | HS | PF | HG | ANOVA | HS vs. HG | |
| Heat exposure for 7 d | ||||||
| Relative length, cm/kg·BW | ||||||
| Duodenum | 15.4 ± 0.6 | 15.4 ± 0.7 | 14.4 ± 0.3 | 15.0 ± 0.4 | 0.330 | 0.545 |
| Jejunum | 34.7 ± 1.3b | 43.7 ± 2.0a | 34.5 ± 1.9b | 36.9 ± 1.5* | 0.003 | 0.023 |
| Ileum | 33.9 ± 1.1b | 45.5 ± 2.3a | 33.2 ± 2.2b | 37.7 ± 0.8* | 0.001 | 0.010 |
| Relative weight, g/kg·BW | ||||||
| Duodenum | 5.7 ± 0.3 | 5.1 ± 0.2 | 5.1 ± 0.3 | 5.3 ± 0.2 | 0.135 | 0.502 |
| Jejunum | 14.1 ± 0.5a | 12.7 ± 0.4a,b | 11.8 ± 0.6b | 12.4 ± 0.2 | 0.016 | 0.578 |
| Ileum | 11.6 ± 0.5a | 10.1 ± 0.2b | 8.7 ± 0.6c | 9.1 ± 0.2* | 0.001 | 0.005 |
| Relative weight/relative length, g/cm | ||||||
| Duodenum | 0.38 ± 0.02 | 0.33 ± 0.02 | 0.36 ± 0.02 | 0.36 ± 0.01 | 0.384 | 0.342 |
| Jejunum | 0.39 ± 0.01a | 0.30 ± 0.02b | 0.35 ± 0.02a,b | 0.34 ± 0.02 | 0.012 | 0.141 |
| Ileum | 0.32 ± 0.01a | 0.22 ± 0.01b | 0.27 ± 0.02b | 0.24 ± 0.01 | 0.001 | 0.173 |
| Heat exposure for 14 d | ||||||
| Relative length, cm/kg·BW | ||||||
| Duodenum | 11.9 ± 0.4 | 12.4 ± 0.3 | 11.8 ± 0.1 | 12.1 ± 0.4 | 0.342 | 0.492 |
| Jejunum | 32.6 ± 1.1a | 32.8 ± 0.8a | 28.5 ± 0.9b | 32.4 ± 1.7 | 0.009 | 0.867 |
| Ileum | 32.4 ± 1.4a | 33.8 ± 1.4a | 28.0 ± 1.0b | 30.6 ± 0.8 | 0.014 | 0.072 |
| Relative weight, g/kg·BW | ||||||
| Duodenum | 5.2 ± 0.4 | 4.7 ± 0.3 | 4.5 ± 0.3 | 4.4 ± 0.2 | 0.291 | 0.446 |
| Jejunum | 12.4 ± 0.4a | 9.2 ± 0.4b | 8.5 ± 0.3b | 9.5 ± 0.2 | <0.001 | 0.518 |
| Ileum | 9.6 ± 0.3a | 7.9 ± 0.4b | 7.6 ± 0.4b | 8.2 ± 0.2 | 0.001 | 0.545 |
| Relative weight/relative length, g/cm | ||||||
| Duodenum | 0.42 ± 0.02 | 0.39 ± 0.02 | 0.38 ± 0.01 | 0.36 ± 0.02 | 0.202 | 0.257 |
| Jejunum | 0.36 ± 0.01a | 0.29 ± 0.01b | 0.31 ± 0.01b | 0.30 ± 0.02 | 0.001 | 0.451 |
| Ileum | 0.30 ± 0.01a | 0.24 ± 0.01b | 0.28 ± 0.02a,b | 0.27 ± 0.02 | 0.017 | 0.216 |
1NC, normal control group, 22 °C, ad libitum feed basal diet; HS, heat stress group, 32 °C, ad libitum feed basal diet; PF, pair-fed group, 22 °C, received food equivalent to that consumed by the HS group on the previous day; HG, guanidinoacetic acid group, 32 °C, ad libitum feed basal diet with 0.6 g/kg guanidinoacetic acid.
a,bMeans within a row without a common superscript differ significantly among the NC, HS, and PF groups (P < 0.05).
*Indicates a significant difference between HS vs. HG (P < 0.05). The results were expressed as the means ± SE.