The aim of this study was to evaluate the effect of pulp and leaves of Glycyrrhiza glabra to reduce the ruminal biogas production in sheep. Five experimental diets of two levels of Glycyrrhiza glabra pulp (GGP) and Glycyrrhiza glabra leaves (GGL) at 150 and 300 g/kg dry matter (DM) were assessed for biogas production and fermentation parameters. Diets were control (diet without GGP or GGL), GGP15 (diet contains GGP at 150 g/kg DM), GGP30 (diet contains GGP at 300 g/kg DM), GGL15 (diet contains GGL at 150 g/kg DM), and GGL30 (diet contains GGL at 300 g/kg DM). Inclusion of 150 and 300 g/kg GGP and 300 g/kg GGL decreased (P < 0.0001) asymptotic biogas production (A), fermentation rate (μ), biogas production at 24 h of incubation (GP₂₄), apparent degraded substrate (ADS), in vitro organic matter disappearance (OMD), and metabolizable energy (ME). Microbial protein biomass (MP) was improved (P = 0.003) by GGP15, GGL15, and GGL30 versus control. Total VFAs (P = 0.003), acetate (P = 0.009), and butyrate (P = 0.002), CH₄ (mmol and mL/g OMD), CO₂ (mmol and mL/g OMD) (P = 0.0003 and P = 0.0002, respectively), were decreased in GGP15, GGP30, and GGL30 diets versus control. Acetate to propionate ratio (Ac/Pr) was decreased (P = 0.038) in GGL30 diet compared to other diets. Replacing GGP and GGL with alfalfa reduced NH₃-N concentration (P = 0.022), total protozoa (P < 0.0001), Isotricha spp. (P = 0.047), Dasytricha spp. (P = 0.067), subfamilies of Entodiniinae (P < 0.0001), and Diplodiniinae (P = 0.06). Results suggested that inclusion of dietary GGL at 150 g/kg dry matter positively modified some rumen parameters such as microbial protein production, protozoa population, and NH₃-N concentration, which may be useful economically in ruminant animals and decreasing of environmental pollution.

The effects of patchouli essential oil (PEO) as an alternative to antibiotics on ruminal methanogenesis, feed degradability, and enzyme activities were evaluated. The basal substrate was incubated without additives (control, CTL) and with monensin (MON, 6 μM/g DM) or patchouli essential oil (PEO, 90 μg/g DM) for 24 h. In three different runs, the gas production (GP) was recorded at 2, 4, 8, 12, and 24 h of incubation using a semi-automatic system. The results revealed that MON had decreased (P < 0.05) the net GP and CH₄ production and digestible and metabolizable energy relative to PEO supplementation. The in vitro truly degraded organic matter was not influenced by PEO application, while was reduced (P = 0.027) with MON. Both PEO and MON had similar reducing effect on the activity of carboxymethylcellulase (P = 0.030), in vitro truly degraded neutral detergent fiber (P = 0.010), NH₃-N concentrations (P = 0.012), acetate proportion (C2, P = 0.046), C2 to C3 ratio (P = 0.023), and total protozoal count (P = 0.017). Both additives recorded similar elevating potential on the α-amylase activity (P = 0.012), propionate (C3) proportion (P = 0.011), and microbial protein (P = 0.034) compared with CTL. Effects of MON and PEO on ruminal feed degradability, microbial enzyme activities, and total protozoa counts may be responsible for modifying rumen fermentation ecology. Addition of PEO may act as a desirable alternative rumen modifier for MON in ruminant diets.

Two experiments were conducted to investigate the effect of supplemental bentonite on performance, blood, and fermentation characteristics in Zandi lambs. In experiment 1, 20 Zandi male lambs (initial BW, 17.5 ± 1.6 kg and 110 ± 5 days old) were randomly assigned into four groups of five animals in each. The experimental treatments were (1) control (no Pb and bentonite), (2) 15 mg/kg DM Pb as Pb acetate and no bentonite, (3) 15 mg/kg DM Pb as Pb acetate and 1.5% bentonite, and (4) 15 mg/kg DM Pb as Pb acetate and 3% bentonite. The dietary treatments had no significant effect on dry matter intake of experimental lambs. Feed required per unit of weight gain was more (P < 0.05) in lead-exposed lambs in group 2 compared to the control and bentonite supplemented groups. Serum glucose, urea nitrogen, cholesterol, HDL, and LDL concentrations was similar among the treatments. In experiment 2, an in vitro gas production technique was used to evaluate the effects of bentonite supplementation on the gas production parameters of lead-polluted diets. The rate and amount of gas production was higher for bentonite supplemented groups (P < 0.01). Asymptotic gas production (b), metabolizable energy, and concentration of short chain fatty acids were lower (P < 0.05) for lead-polluted non-supplemented diet (group 2) as compared to the bentonite supplemented and control groups. It was concluded that bentonite supplementation favorably modified ruminal fermentation pattern and improved feed conversion ratio in growing lead-exposed lambs.