اثر ‌اسانس گونه‌های مختلف‌ آویشن بر فراسنجه های تولید گاز‌، قابلیت هضم و فراسنجه‌های ‌تخمیری شکمبه ‌ای در شرایط آزمایشگاهی

Two experiments were conducted to evaluate the effect of essence of various species of Thymus on in vitro gas production parameters and digestibility of dry matter and organic matter. Various species of Thymus medicinal plant was collected from different area: Shriaz (Zatari‌‌a m‌ultiflora‌‌), Esfarayen (Thymus transcaspicus lamiaceae), Shahrood (Thymus fallax), Golestan forestry (Thymus transcauasicus) and Gorgan (Thymus vulgaris). Essence of collected samples was taken by macro wave at 110 0C and 450 nm for 45 minutes. Treatments were including: 1) control containing basal diet with forage: concentrate ratio 50:50 (without essence) and treatment 2 till 6 containing basal diet and essence of various species. Results showed that adding essences from various species had significant effects on potential gas production and gas production rate (p<­0.05) as treatment of control had highest potential gas production (396.6 ml per g dry matter) compared to other treatments. It was also observed that there were significant differences among essence containing treatments compared with control treatment on estimated parameters (p<0.05). The use of essence caused significant decrease in pH of culture medium compared to control treatment (p<0.05). In this experiment, there were no significant differences among various treatments in DM and OM digestibility (p<‌0.05). However, treatments that containing essence had higher microbial biomass production and microbial biomass production efficiency. It can be concluded that essence of different thymus varieties has the potential to affect ruminal fermentation efficiency and further researches is needed to determine the optimal doses of different thymus varieties essence.