This study aimed to evaluate in vitro and in vivo dietary supplementation with different levels of natural or nano-zeolite forms on rumen fermentation patterns and nutrient digestibility. In the in vitro experiment, a basal diet (50% concentrate: 50% forage) was incubated without additives (control) and with natural zeolite (10, 20, 30 g/kg DM) or nano-zeolite (0.2, 0.3, 0.4, 0.5, 1.0 g/kg DM) for 24 h to assess their effect on ruminal fermentation, feed degradability, and gas and methane production using a semi-automatic system of in vitro gas production (GP). The most effective doses obtained from the in vitro experiment were evaluated in vivo using 30 Barki goats (26 ± 0.9 SE kg body weight). Goats were allocated into three dietary treatments (n = 10/treatment) as follows: control (basal diet without any supplementations), natural zeolite (20 g/kg DM diet), and nano-zeolite (0.40 g/kg DM diet). The in vitro results revealed that only the nano-zeolite supplementation form quadratically (p= 0.004) increased GP, and the level of 0.5 g/kg DM had the highest GP value compared to the control. Both zeolite forms affected the CH₄ production, linear, and quadratic reductions (p < 0.05) in CH₄ (mL/g DM), consistent with linear increases in truly degraded organic matter (TDOM) (p = 0.09), and propionate molar proportions (p = 0.007) were observed by nano zeolite treatment, while the natural form of zeolite resulted in a linear CH₄ reduction consistent with a linear decrease (p = 0.004) in NH₃-N, linear increases in TDOM (p = 0.09), and propionate molar proportions (p = 0.004). Results of the in vivo experiment demonstrated that the nutrient digestibility was similar among all treatments. Nano zeolite enhanced (p < 0.05) the total short-chain fatty acids and butyrate concentrations, while both zeolite forms decreased (p < 0.001) NH₃-N compared to the control. These results suggested that both zeolite supplementation forms favorably modified the rumen fermentation in different patterns.

Essential oils (EOs) and their active components are attracting a lot of attention as sustainable feed additives due to their known antimicrobial properties against a variety of microorganisms, including bacteria, protozoa, and fungi. They also have biological therapeutic, antioxidant, and flavor properties. They can be used for modifying the rumen environment and improving animal productivity. The present study was designed to investigate the effect of supplementation with 2.5 and 5 g/head/day of an essential oils blend (EOB) of clove, oregano, and juniper in equal proportions on milk production and quality, and physiological status of early lactating Holstein dairy cows for 8 weeks of treatment followed by 8 weeks of posttreatment. The results revealed an improvement in milk yield (p ≤ 0.02) and feed efficiency (p ≤ 0.001) with EOB at a dose of 2.5 g/head/day. The percentages of milk protein and lactose were increased (p ≤ 0.03) with a high dose of EOB inclusion during the treatment period as compared with the control group. Milk fat percentage, fat-corrected milk, and energy-corrected milk were not significantly affected by EOB supplementation. The supplementation of EOB tended to decrease milk total bacterial and somatic cell counts when compared to the control group. The supplementation of EOB at both doses increased serum total protein (p ≤ 0.02) and globulin (p ≤ 0.05), and decreased cholesterol level (p ≤ 0.001) and creatinine (p ≤ 0.001) as compared to the control group. Furthermore, the results show that the low dose of EOB had more desirable effects on milk yield, milk total bacterial count, milk somatic cell count, and feed efficiency than the high dose, suggesting that lower doses may not inhibit rumen microbial populations. Moreover, the low doses of EOB could be used as sustainable natural alternatives to antibiotics in livestock diets.

Two types of modified nano-montmorillonite (MNM) were developed by ion-exchange reactions using two different surfactants; sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CETAB), to prepare MNM_SDS and MNM_CETAB, respectively. Both MNM types were on the nano-scale and had higher cation-exchange capacity values than NM clay. The MNM_CETAB had the highest zeta potential (−27 mV) compared with the other clays. Effects of MNM types on in vitro ruminal batch culture fermentation, nutrient degradability, and methane (CH₄) emission compared with monensin were evaluated in vitro using a semi-automatic gas production system. The experimental treatments were the control (0 supplementations), monensin (40 mg/kg DM), and NM (5 g NM/kg DM), and two levels of MNM_SDS and MNM_CETAB were supplemented at 0.05 (low) and 0.5 (high) g/kg DM to the control basal feed substrate. Among the experimental treatments, the high dose of both MNM types reduced (p < 0.01) CH₄ production and ammonia concentrations compared with the control, while only MNM_CETAB treatment tended to increase (p = 0.08) the truly degraded organic matter compared with monensin. All MNM treatments increased (p < 0.01) acetate molar proportions compared with monensin. The high MNM_CETAB increased (p < 0.01) the in vitro ruminal batch culture pH compared with the control and monensin. The MNM_CETAB supplemented at 0.5 g/kg DM is the most efficient additive to reduce CH₄ emission with the advantage of enhancing the in vitro nutrient degradability of the experimental feed substrate. These results indicated that MNM could modulate the in vitro ruminal fermentation pattern in a dose- and type-dependent manner.

The objectives of this study were to characterise four essential oils (EO) chemically and to evaluate their effect on ruminal fermentation and methane emission in vitro. The investigated EO were isolated from Achillea santolina, Artemisia judaica, Schinus terebinthifolius and Mentha microphylla, and supplemented at four levels (0, 25, 50 and 75 μl) to 75 ml of buffered rumen fluid plus 0.5 g of substrate. The main components of the EO were piperitone (49.1%) and camphor (34.5%) in A. judaica, 16-dimethyl 15-cyclooactdaiene (60.5%) in A. santolina, piperitone oxide (46.7%) and cis-piperitone oxide (28%) in M. microphylla, and γ-muurolene (45.3%) and α-thujene (16.0%) in S. terebinthifolius. The EO from A. santolina (at 25 and 50 μl), and all levels of A. judaica increased the gas production significantly, but S. terebinthifolius (at 50 and 75 μl), A. santolina (at 75 μl) and all levels of M. microphylla decreased the gas production significantly in comparison with the control. The highest levels of A. santolina and A. judaica, and all doses from M. microphylla EO inhibited the methane production along with a significant reduction in true degradation of dry matter and organic matter, protozoa count and NH₃-N concentration. It is concluded that the evaluated EO have the potential to affect ruminal fermentation efficiency and the EO from M. microphylla could be a promising methane mitigating agent.

The present study aimed to evaluate the potential of improving the feeding value of Egyptian clover (EC), ryegrass (R), triticale (T), barley (B), and oats (O) monoculture, or Egyptian clover mixed with ryegrass (EC+R), oats (EC+O), barely (EC+B), and triticale (EC+T) at 75:25% seeding rate, respectively, during two successive winter seasons of 2018/19 and 2019/20. Harvesting of plots was carried out at 5 cm stubble height after 60, 100, and 140 days from sowing. The in vitro nutritive value and ruminal fermentation of the monoculture and intercropping containing EC were evaluated. Green forage yield of EC was higher than other plants with about 160% of fresh forage compared with T, O, or EC+T intercropping. The highest crude protein (CP) concentration was noted in EC, while the lowest (p < 0.001) concentration was observed in T, which had the highest fiber fractions content. Ryegrass had the highest net in vitro gas production (GP), while EC+R had the lowest GP (p < 0.05). The EC increased dry matter and organic matter degradability. EC and R reduced protozoal count, while total volatile fatty acids (VFA), acetate, and propionate were increased with B and EC+T intercropping (p < 0.05). Overall, intercropping of EC with grass of triticale or ryegrass at mixing rates of 75:25% resulted in improving fresh and dry forage yields. The legume–grass intercropping improved the protozoa count partitioning factor as an index of microbial protein synthesis and total VFA concentration.