Table 4 Effects of dietary essential oils or forages containing essential oils on nitrogen metabolism and N2O emissions from excreta in ruminants
Reference | Essential oil source (plant/extract) | Animal species | DMI, production performance, or N metabolism related indicators | N excretion or N retention | N2O emissions |
|---|---|---|---|---|---|
Wanapat et al. [154] | Garlic powder | Steers | –DMI; –CP digestibility; ↓Ruminal NH3-N; ↓BUN | ↓UN; –FN; ↑N retention | NR |
Wanapat et al. [157] | Peppermint powder/garlic powder | Beef cattle | –DMI; –Ruminal NH3-N; –BUN; ↓CP digestibility (peppermint powder) | –UN; –FN; ↑N retention (garlic powder); ↓N retention (peppermint powder) | NR |
Tekippe et al. [158] | Cinnamaldehyde and eugenol | Dairy cows | –DMI; –Milk yield; –Milk composition; ↑Feed efficiency; ↑MUN; –CP digestibility | ↑UN; –FN; –Milk N; –NUE | NR |
Oh et al. [159] | Carvacrol, eugenol and thymol | Dairy cows | –DMI; –Milk yield; –Milk composition; –CP digestibility; –MUN ↑Milk lactose percentage; ↓MUN | –UN; –FN; –Milk N; –NUE | NR |
Ribeiro et al. [155] | Thyme (Thymus vulgaris) | Sheep | –DMI; –ADG; –CP digestibility; –Ruminal NH3-N | ↓UN; –FN; –N retention | NR |
Benchaar [160] | Thymol | Dairy cows | –DMI; –CP digestibility; –Ruminal NH3-N; –Milk yield; –Milk composition | –UN; –FN; –Milk N; –NUE | NR |
Muñoz-Cuautle et al. [161] | Oregano (Lippia graveolens) | Lamb | –DMI; –ADG; –FCR; –Meat quality; –Ruminal NH3-N | –UN; –FN; –N retention; –NUE | NR |