Biological activities of Juniperus phoenicea essential oil and impact on in vitro ruminal fermentation in sheep
Juniperus phoenicea L. is a medicinal plant belonging to the Cupressaceae family. The present study was conducted to evaluate the in vitro antioxidant and antimicrobial activities of Juniperus phoenicea essential oils (JPEO) and its effects on fermentation kinetics in sheeps. Our result firstly indicated that the use of GC-MS allowed to the identification of 48 compounds in JPEO and the principal compound is α-pinene. JPEO is characterized by an excellent antioxidant (IC50 = 93.23 µg/mL) against the DPPH radical, but still lower when compared to that of ascorbic acid (IC50 = 61.30 µg/mL), used as reference antioxidant molecule. Importantly, the JPEO showed a significant effect against the entire tested bacterial flora and the highest zone of inhibition was found against Bacillus subtilis (zone of inhibition 2.85 ± 0.02 mm). A variation in the antimicrobial properties of JPEO according to the microorganism species was observed. Indeed, the zone of inhibition showed a great effect against Gram+ strains compared to the Gram-. Interestingly, the different doses of JPEO with sheep ruminal fluid exert a significant effect, but in a way that results in inhibiting ruminal gas production (GP) after 24 h incubation. More importantly, we found that volatile fatty acids (AGV), organic matter digestibility (OMD), and metabolizable energy (ME) significantly decreased with increasing essential oil level. We concluded that the incorporation of essential oils in the ration did not improve the digestibility parameters of the sheep, but it did decrease the production of greenhouse gases.