Table 6.
Effect of essential oils on cecal bacterial populations of broilers on day 21
| Item a | Total bacteria | Lactobacillus | Escherichia | C. perfringens |
|---|---|---|---|---|
| Treatment | ||||
| Basal diet, unchallenged | 11.16 | 8.52 | 9.77 | 3.05 |
| 60 mg/kg EO, unchallenged | 11.50 | 8.86 | 9.53 | 2.38 |
| 120 mg/kg EO, unchallenged | 11.41 | 9.16 | 9.51 | 2.83 |
| 240 mg/kg EO, unchallenged | 11.42 | 8.69 | 9.41 | 2.41 |
| Basal diet, challenged | 11.28 | 8.60 | 9.28 | 3.68 |
| 60 mg/kg EO, challenged | 11.43 | 9.02 | 9.42 | 3.63 |
| 120 mg/kg EO, challenged | 11.40 | 9.06 | 9.46 | 3.30 |
| 240 mg/kg EO, challenged | 11.37 | 8.70 | 9.34 | 3.39 |
| SEM | 0.041 | 0.068 | 0.085 | 0.110 |
| P-value | ||||
| Challenge | 0.973 | 0.785 | 0.316 | <0.001 |
| EO | 0.190 | 0.022 | 0.952 | 0.327 |
| Challenge × EO | 0.842 | 0.916 | 0.783 | 0.466 |
| Linear b | 0.299 | 0.673 | 0.566 | 0.270 |
| Quadratic b | 0.129 | 0.002 | 0.927 | 0.606 |
a Values are means of eight replicates per treatment, and expressed as log10 (copy/g digesta). EO, essential oils; unchallenged, birds without challenge of C. perfringens; challenged, birds challenged with C. perfringens from day 14 to 20; SEM, pooled standard error of the mean; Challenge × EO, interaction between C. perfringens challenge and EO supplementation
b When interaction between C. perfringens challenge and EO supplementation was not significant, linear and quadratic polynomial contrasts were performed on the main-effect means to EO dosages