Comparing Chemical Composition and Phenolic Compounds of Some Herbals as Potential Feed Additives in Ruminant Nutrition

The chemical composition and phenolic compounds of eight herbals (Alpinia officinarum, Artemisia absinthium, Cuminumcyminum, Dittrichia viscosa, Mentha rotundifolia L., Nigella sativa, Rosmarinus officinalis L., and Zingiber officinale) were evaluated. Feed components were determined by proximate analysis, whereas phenolic and tannin compounds were analyzed by colorimetric procedures. The crude protein content of the herbal samples varied widely, being particularly high for Nigella sativa and low for Alpinia officinarum and Rosmarinus officinalis. The highest contents of total extractable phenols (TEP) and total extractable tannins (TET) were observed in the Cuminumcyminum and Dittrichiaviscose whereas herbals, Nigella sativa and Zingiber officinale showed lower concentrations. The tannin concentration varied considerably between species, but in general, the plants investigated in this study had low tannin contents (except for Alpinia officinarum). Based on the results above, it could be concluded that a large reserve of herbal species in the local flora is available that could be potentially used as additives for livestock feeding. These herbs appear to be promising alternatives to antibiotics in altering rumen fermentation and reducing methane production in ruminants.