The aim of the present study was to investigate the effects of di-sodium fumarate (DSF) and thyme essential oil (TEO) solely and simultaneously on ruminal fermentation properties and microbial abundance. A dual-flow continuous culture system (DFCC) with eight 1400-mL fermenters was used in a period of 12 d that divided to 9 d for adaptation and 3 d for sampling. Fermenters were fed 100 g d-1 [dry matter (DM) basis] of a 50:50 alfalfa hay:concentrate ration. Treatments were no additive (control), 10 mM of DSF, 125 µL/L of TEO and simultaneous use of 10 mM of DSF, and 125 µL/L of TEO (SIMTF). Treatments had no effect on organic matter (OM) and neutral detergent fiber (NDF) disappearance, total and cellulolytic bacteria and protozoa abundance, large peptides and N-NH3 concentration of the effluent, N-NH3 and dietary N flow and molar proportions of acetate (C2), butyrate and isovalerate. DSF significantly increased crude protein (CP) degradation, the molar proportion of propionate (C3) and reduced C2:C3ratio (p <0.05). TEO decreased (p <0.05) DM disappearance (-14.4%) and total volatile fatty acid (-19.4%) concentration, relative to the DSF. Relative to the control, small peptide plus amino acid N concentration was higher (p <0.05) in TEO treatment and DSF. SIMTF increased (p <0.05) the acid detergent fiber (ADF) disappearance and decreased the N-NH3 concentration from zero to 4 h after feeding. Total N, non-ammonia N and bacterial N flow and efficiency of microbial CP synthesis increased with SIMTF. Findings demonstrated that feed efficiency and ruminal fermentation were improved by the simultaneous use of DSF and TEO. Manuscript profile

The objective of this study was to investigate in vitro effect of Malva sylvestris leaf extract (at 0, 25, 50 and 100 µL/30 mL of medium) on sheep ruminal cellulolytic and total viable bacteria growth, protozoa populations, methane production, neutral detergent fiber degradability (NDFD) and fermentation efficiency of oat hay. The addition of Malva sylvestris leaf extract at 25, 50 and 100 µL led to a linear increase (P<0.01) in vitro truly degraded dry matter (INTDDM), NDFD and partitioning factor (PF) of oat hay and decrease (P<0.01) methane emission after 24 hours of incubation. The addition of Malva sylvestris leaf extract resulted in a decrease (P<0.01) in potential of gas production at 25 and 50 µL and increase in lag time (0.95, 1.01 and 1.13 h relative to 0.61 h), constant rate of gas production (b)and gas produced at half-life (c)at 25, 50 and 100 µL. The addition of this extract decreased a number of total protozoa and Entodinium, Isotrichae, Diplodinium and Ophryoscolex species (P<0.01). The number of total and cellulolytic bacteria was not influenced by the addition of Malva sylvestris leaf extract. The result of this study demonstrated that Malva sylvestris extract had some potential for improving the rumen fermentation. Manuscript profile

Nine Holstein dairy cows (630±50 kg) were used in a completely randomized design with repeated measures (two 21 d periods) to investigate the effects of disodium fumarate (DSF, 160 g/d), thyme essential oil (TEO, 9 mL/d) and simultaneous use of TEO and DSF (SIMTF, 160 g/d DSF and 9 mL/d TEO) on performance, apparent digestibility, blood metabolites, rumen microbial communities and fermentation characteristics. Dry matter intake and apparent digestibility (except for TEO), milk production and composition were not affected by the treatments. Relative to the control (CON, no additive), organic matter apparent digestibility tended to decrease by TEO supplementation (578 vs. 599 g/kg). Serum urea nitrogen concentration was lower in TEO than CON (9.8 vs. 10.9 mg/dL). Also, DSF supplementation significantly increased the molar proportion of propionate and the glucogenic: non-glucogenic ratio of volatile fatty acids (VFA) and decreased the molar proportion of butyrate. Supplementation of DSF and SIMTF resulted in a significantly decrease in the acetate: propionate ratio. Relative to the CON, DSF and SIMTF supplementation significantly increased serum glucose concentration. TEO supplementation decreased rumen fluid ammonia nitrogen and increased large peptides and small peptides plus amino acid nitrogen concentration. Rumen total and cellulolytic bacteria and protozoa abundance were not affected by treatments (except for total bacteria that decreased by TEO). Results of the present study demonstrated that the simultaneous use of DSF and TEO relative to DSF alone could not have synergistic effects on performance, ruminal fermentation and serum metabolites of dairy cow. DSF can be used as a ruminal glucogenic precursor and resulted in an increase in the serum concentration of glucose in dairy cows. Manuscript profile