Herbal Plant Case Study

Herbal plants were investigated for possible use as a modifiers of rumen fermentation.
In the present study, considerable differences were observed between treatments in levels of in vitro gas production. All levels of HP, with the exception of the P15 treatment, significantly increased gas production compared to control. This is similar to the observations of Menke and Steingass (15), who also reported an effect of herbal plant on total gas production, and gas production parameters (b and c). It has been strongly suggested that the amount of gas production is positively correlated with diet digestibility. Therefore, increasing the amount of gas production at increased concentrations of medicinal plants may represent improved digestibility

Similar to our study, Joch et al. (6) observed that in vitro GP increased significantly with herbal and plant extracts supplementation. They noted that the increase of gas volume might be due to the inclusion of soluble sugars in the reaction mixture. In this case, the gas production decline could be due to the anti-microbial effect of HP at the high concentrations. Compared with control, addition of HP into the basal diet resulted in a decrease of Methane production (P < 0.05). These findings are consistent with prior results of different types of herbal plant supplementation to diets that showed addition of herbal plant and its component into the basal diet resulted in a decrease of Methane production (P < 0.05). Decreasing ruminal methane output could improve animal efficiency due to reduced losses of feed energy. The reduction in methane may be due to the inhibition of fiber degradation and decline in methanogenic archaea. The trace compounds in the herbal plant may inhibition of methanogenic archaea bacteria and or microbial fermentation, subsequently decreasing methanogenesis. Additionally, a decrease in methane

(21) noted that a mix of essential oil, including thymol reduced the rate of amino acid deamination and prevented the growth of a specific group of ammonia producing- bacteria. The prevention of amino acid deamination has practical implications, like potentially altering site of protein digestion from the rumen to the intestine. Castillejos et al. (22) showed that supplementation of thymol to rumen liquid caused a reduction in the NH3-N and an accumulation of amino acids nitrogen. Wallace et al. (20) expressed that amount of ammonia-nitrogen production from amino acids in rumen liquid was by dietary herbals. Feeding herbal plants reduced the numbers of protozoa, which appears to be mediated by the active compounds in these plants (23). The results showed that ruminal pH were not affected by herb alone or in combination supplement. Similarly, Castillejos et al. (22) also reported that plant essential oil mixtures did not affect rumen pH or organic matter digestibility. Although previous studies have offered mixed reports, it seems that these differing results may be partially explained by the experimental conditions, including the type of diets used in the experiments, plant species and/or their active composition used, and as well as the rumen pH. Calsamiglia et al. (24) observed that effects of plant essential oils are associated with pH and diet, and their use could be beneficial under specific conditions. Plants contain one or more predominant active