Table 5.
Effect of various EO and their compounds on rumen microbial population.
| Sources | Test system/dose | Diet | Total bacteria | Protozoa | Methanogens | F.S | R.F | R.A | B.F | References |
|---|---|---|---|---|---|---|---|---|---|---|
| Oregano essential oil | In vitro (13, 52, 91, and 130 mg/L | F:C (65.5:34.5) | = | NF | NF | ↓ | = | = | = | (239) |
| Oregano oil and carvacrol | Cannulated cows (50 mg/kg of DM) | TMR | NF | = | NF | NF | NF | NF | NF | (240) |
| Oregano essential oil |
In vivo sheep 4 g/d 7 g/d |
F:C (65.5:34.5) |
↑ = |
↓ ↓ |
NF |
↑ = |
↑ ↓ |
↑ = |
NF | (241) |
| Essential oil-cobalt | Goat 52 mg/d 91 mg/d |
Concentrate |
↓ ↓ |
NF |
= = |
↑ ↓ |
↓ = |
↓ = |
↓ = |
(233) |
| Plant-derived EO (carvacrol, eugenol and thymol) |
In vitro and vivo both Control LCP LCP 35 g/d |
TMR | NF | = = = |
NF | NF | NF | NF | NF | (242) |
| Mixture of cinnamaldehyde, thymol, and eugenol | Heifer 1 g/kg substrate 2 g/kg substrate |
F:C (60:50) 24 h | NF |
= ↑ |
NF |
= = |
= ↑ |
↑ = |
= ↑ |
(243) |
| Thymol:carvacrol |
In vitro
0:100, 20:80, 40:60, 60:40, 80:20, 100:0 |
Rumen culture of bovine |
= ↑ ↓ ↑ ↑ ↑ |
= ↑ ↓ ↑ ↑ ↑ |
NF | NF | NF | NF | NF | (244) |
| Java cardamom |
In vitro cow 25 mg/l 50 mg/l 75 mg/l 100 mg/l |
F:C (60:40) | NF |
= = = = |
NF | NF | NF | NF | NF | (245) |
| Blend of cinnamaldehyde and garlic oil | In vitro 0.0043% of DM | F:C (50:50) | NF | = | NF | NF | NF | NF | NF | (246) |
| Anise EO Anise extract |
In vitro rumen buffer 250 μL /30 ml 500 μL /30 ml 750 μL /30 ml 1,000 μL /30 ml 250 μL /30 ml 500 μL /30 ml 750 μL /30 ml 1,000 μL /30 ml |
F:C (40:60) | NF |
= = = = = = = = |
NF | NF | NF | NF | NF | (247) |
F:C., forage to concentrate ratio; TMR, total mixed ration; NF, not found; ↑, increase; ↓, decrease; =, no effect; EO, essential oils; F.S, Fibrobacter succinogenes; R.F, Ruminococcus flavefaciens; R.A, Ruminococcus albus; B.F, Butyrivibrio fibrisolvens; LCP, low CP diet.