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Search Results (370)

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Keywords = in vitro rumen fermentation

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20 pages, 1199 KB  
Article
Interactive Effects of Nypa fruticans Fruit Pellets and Dietary Protein Levels on Rumen Fermentation, Gas Kinetics, and Methane Production In Vitro
by Chaturaphat Rueangchuai, Chanon Suntara, Metha Wanapat, Chanadol Supapong, Pongsatorn Gunun, Nirawan Gunun, Suban Foiklang, Payungsuk Intawicha and Anusorn Cherdthong
Animals 2026, 16(9), 1313; https://doi.org/10.3390/ani16091313 - 24 Apr 2026
Abstract
This study evaluated the effects of Nypa fruticans fruit pellet supplementation combined with different CP levels on rumen fermentation characteristics and CH4 production using an in vitro gas production technique. A 3 × 4 factorial arrangement was used, consisting of three CP [...] Read more.
This study evaluated the effects of Nypa fruticans fruit pellet supplementation combined with different CP levels on rumen fermentation characteristics and CH4 production using an in vitro gas production technique. A 3 × 4 factorial arrangement was used, consisting of three CP levels (12, 14, and 16%) and four levels of Nypa fruticans fruit pellet supplementation (0, 0.5, 1.0, and 1.5% of substrate dry matter), with incubation run included as a random effect in the statistical model. Rumen fluid from Thai native beef cattle was incubated under anaerobic conditions. Gas production kinetics, ruminal pH, ammonia–nitrogen (NH3–N), protozoal populations, digestibility, volatile fatty acids (VFA), and CH4 production were determined. Significant interactions between CP level and Nypa fruticans fruit pellet supplementation were observed for gas production kinetics. Ruminal pH was influenced by CP level at 24 h, while NH3–N increased with higher CP levels but decreased with increasing supplementation. Protozoal populations were reduced by Nypa fruticans fruit pellets. Methane production was affected by CP level, Nypa fruticans fruit pellet supplementation, and their interaction. A clearer reduction was observed at 24 h, particularly at higher supplementation levels. At 24 h of incubation, total VFA, propionate, and butyrate concentrations increased with supplementation, whereas no clear effects were observed at 12 h. In vitro dry matter digestibility was affected at 24 h (p < 0.05), but no effect was observed at 48 h, while organic matter digestibility remained unchanged. In conclusion, Nypa fruticans fruit pellets, in combination with CP level, modified rumen fermentation patterns and were associated with lower CH4 production under in vitro conditions, without negatively affecting digestibility. These findings suggest potential for further in vivo evaluation. Full article
14 pages, 1538 KB  
Article
Blanching Effects of Undaria pinnatifida on Chemical Compositions, Rumen Fermentation Characteristics, Greenhouse Gas Emissions, and Rumen Microbes In Vitro
by Chang-Hyun Baeg, Seung-Min Jeong, Arrynda Rachma Dyasti Wardani, Ji-Yoon Kim, Bu-Gil Choi, Young-Ho Joo, Hye-Seong Kim, Yong-Hyun Do, Jung-Jun Park and Sam-Churl Kim
Agriculture 2026, 16(8), 912; https://doi.org/10.3390/agriculture16080912 - 21 Apr 2026
Viewed by 391
Abstract
This study aims to evaluate the blanching process of wasted Undaria pinnatifida as a ruminant feed source by assessing chemical compositions, in vitro nutrient digestibility, rumen fermentation characteristics, greenhouse gas emissions, and rumen microbes. The blanching process was conducted at different temperatures (15 [...] Read more.
This study aims to evaluate the blanching process of wasted Undaria pinnatifida as a ruminant feed source by assessing chemical compositions, in vitro nutrient digestibility, rumen fermentation characteristics, greenhouse gas emissions, and rumen microbes. The blanching process was conducted at different temperatures (15 vs. 80 vs. 90 °C) and times (2 vs. 4 min) to assess the chemical and mineral contents. Supplementation levels of U. pinnatifida (0 vs. 0.5 vs. 1 vs. 2%) were observed with the blanching process (non-blanching (NBL) vs. blanching (LOS)). Increasing blanching temperature and time decreased (p < 0.05) dry matter, crude ash, and the mineral contents, including sodium, phosphorus, and arsenic. Moreover, LOS treatment increased (p < 0.01) in vitro dry matter and neutral detergent fiber digestibility, ruminal pH, and the acetate-to-propionate ratio, but reduced (p < 0.01) CH4 (mL/g NDFD). Additionally, 2% of LOS treatment reduced the abundance of protozoa, fungi, fibrolytic microbes, methanogenic archaea, Methanobrevibacter ruminantium, Methanosarcina barkeri, and Methanosphaera stadtmanae (p < 0.01). Therefore, blanching at 80 °C for 2 min improved the nutritional profile by reducing antinutritional minerals. Subsequent in vitro fermentation suggested that supplementing the diet with 0.5–1% of LOS improved digestibility and altered fermentation, potentially reducing methane yield (per NDFD). Full article
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11 pages, 220 KB  
Article
Effects of Different Proportions of Corn Silage and Ramie Silage on In Vitro Rumen Fermentation Characteristics and Methane Production
by Honghui Qi, Cheng Gao, Zhicai Li and Duanqin Wu
Animals 2026, 16(8), 1250; https://doi.org/10.3390/ani16081250 - 18 Apr 2026
Viewed by 210
Abstract
This study investigated the interactive effects of corn silage and ramie silage on in vitro rumen fermentation characteristics, aiming to provide a scientific basis and empirical evidence for the rational incorporation of ramie into ruminant diets. Four binary substrate mixtures were formulated based [...] Read more.
This study investigated the interactive effects of corn silage and ramie silage on in vitro rumen fermentation characteristics, aiming to provide a scientific basis and empirical evidence for the rational incorporation of ramie into ruminant diets. Four binary substrate mixtures were formulated based on dry matter (DM) mass ratios of corn silage to ramie silage: 100:0 (CON), 60:40 (R40), 20:80 (R80), and 0:100 (R100). Rumen fluid was collected from three adult Liuyang black goats surgically fitted with permanent rumen cannulas, and a standardized 48 h in vitro batch culture assay was conducted. Results demonstrated that increasing the proportion of ramie silage significantly decreased (p < 0.05) the DM degradation rate, neutral detergent fiber (NDF) degradation rate, acid detergent fiber (ADF) degradation rate, and total gas production per gram of substrate DM. Specifically, CON and R40 exhibited significantly higher values for all four parameters than R80 and R100 (p < 0.05). Methane production was significantly reduced in all ramie-containing treatments relative to CON (p < 0.05), whereas hydrogen production increased progressively with ramie inclusion level, with CON yielding significantly less H2 than both R80 and R100 (p < 0.05). Regarding fermentation parameters, increasing ramie proportion elevated (p < 0.05) both fermentation fluid pH and the acetate-to-propionate ratio, while total volatile fatty acid (TVFA) concentration declined linearly (p < 0.05). TVFA concentrations did not differ significantly between CON and R40, yet both were significantly greater than those in R80 and R100 (p < 0.05). Collectively, these findings indicate that ramie silage is a nutritionally valuable forage with potential as a high-quality partial replacement for conventional silages in ruminant feeding systems; however, its inclusion in corn–ramie mixed silages should not exceed 40% (on a DM basis) to maintain optimal fermentative efficiency and nutrient degradability. Full article
16 pages, 2680 KB  
Article
Effects of Yeast Culture Supplementation Rate on Rumen Fermentation and the Rumen Microbial Community in Kazakh Sheep In Vitro
by Huiying Zhang, Kai Lou, Gulinizier Nueraihemaiti, Yuanyuan Chen, Yan Gao, Jun Zeng, Qing Lin and Xiangdong Huo
Fermentation 2026, 12(4), 203; https://doi.org/10.3390/fermentation12040203 - 17 Apr 2026
Viewed by 261
Abstract
To explore the appropriate supplementation rate of yeast culture (YC) in Kazakh sheep during fattening, the effects of different YC supplementation rates on rumen fermentation parameters and microbial community were studied through in vitro rumen fluid fermentation experiments. A 0.40 g high-concentrate diet [...] Read more.
To explore the appropriate supplementation rate of yeast culture (YC) in Kazakh sheep during fattening, the effects of different YC supplementation rates on rumen fermentation parameters and microbial community were studied through in vitro rumen fluid fermentation experiments. A 0.40 g high-concentrate diet was used as the fermentation substrate, and five groups were added with YC at 0% (CK), 1.25% (YC1), 2.5% (YC2), 3.75% (YC3) and 5% (YC4) of dietary dry matter, respectively. Anaerobic fermentation was carried out for 48 h in 60 mL fermentation broth. The results showed that the 48 h GP and microbial crude protein (MCP) concentration in all YC supplementation groups were significantly higher than those in the CK group (p < 0.05). The concentrations of total volatile fatty acids (TVFA) and propionate in the YC1 and YC2 groups were significantly increased and the A/P ratio in the two groups was significantly decreased (p < 0.05). The Multi-factor Comprehensive Evaluation Index (MFAEI) calculation indicated that 1.25% was appropriate. The YC1 and YC2 groups significantly increased the richness and diversity of rumen bacterial communities (Chao1 and Shannon indices, p < 0.05), and significantly increased the relative abundance of Bacteroidota and NK4A214_group (p < 0.05), while significantly decreasing the relative abundance of the potential pathogenic bacterium Campylobacter (p < 0.05). Ustilago abundance was significantly suppressed in all the YC-supplemented groups (p < 0.05). The most effective YC supplementation rate among the tested doses was 1.25% according to the MFAEI and key microbial indicators. The results suggest that dietary supplementation of 1.25% YC (dry matter basis) may beneficially modulate rumen fermentation parameters under in vitro conditions, providing a reference for further in vivo studies on its application in fattening Kazakh sheep. Full article
(This article belongs to the Special Issue Ruminal Fermentation: 2nd Edition)
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23 pages, 5630 KB  
Article
Rumen–Plasma–Milk Metabolomics Profiling Revealed Metabolic Alterations Associated with Milk Fat Synthesis in Chinese Holstein Cows
by Huimin Zhang, Sam Carie Kollie, Tianyu Xia, Zhendong Yang, Marazi Tanaka Ian, Ahmed A. Elolimy, Wanqiong Wang, Dongsheng Lu, Yi Li, Mingxun Li, Juan J. Loor, Yongjiang Mao and Zhangping Yang
Animals 2026, 16(8), 1136; https://doi.org/10.3390/ani16081136 - 8 Apr 2026
Viewed by 484
Abstract
Milk fat synthesis in dairy cows is a complex process affected by ruminal fermentation, systemic metabolism, and mammary gland activity. To explore the metabolic interplay across these systems, a multi-tissue metabolomics approach (rumen fluid, plasma, and milk) using ultra-high-performance liquid chromatography–mass spectrometry was [...] Read more.
Milk fat synthesis in dairy cows is a complex process affected by ruminal fermentation, systemic metabolism, and mammary gland activity. To explore the metabolic interplay across these systems, a multi-tissue metabolomics approach (rumen fluid, plasma, and milk) using ultra-high-performance liquid chromatography–mass spectrometry was used to identify metabolic differences between Chinese Holstein cows with high (H-MF, 5.82 ± 0.41%) and low (L-MF, 3.60 ± 0.12%) milk fat content under the same diet. The bovine mammary epithelial cells (BMECs) were also cultured to evaluate the impact of a key metabolite, malic acid (MA), on lipid metabolism. Our findings reveal distinct metabolic profiles across rumen fluid, plasma, and milk, with 96, 109, and 79 differential metabolites, respectively, between the L-MF and H-MF groups. In rumen fluid, H-MF cows showed higher levels of lauric acid and succinic acid, linked to fatty acid biosynthesis, while the L-MF cows had elevated citraconic and orotic acids, associated with amino acid metabolism and liver stress. Plasma from the H-MF cows contained higher β-hydroxybutyric acid, methionine sulfoxide, and phosphatidylcholine, supporting lipogenesis, whereas L-MF plasma showed increased 3-hydroxy-L-proline, indicating tissue catabolism. In milk, the L-MF cows had higher MA, while the H-MF cows exhibited elevated L-carnitine, linked to fatty acid β-oxidation. Metabolite trend analysis during rumen fluid–plasma–milk showed that 211 metabolites were classified into 8 profiles. Profile 1 had the largest number of metabolites whose levels were down-regulated from rumen to plasma and enriched in lipid metabolism. Profile 3 (mainly related to amino acid metabolism) and profile 4 (mainly related to energy metabolism) exhibited opposite trends from plasma to milk. In vitro, 200 μM of MA reduced the triglyceride content in BMECs and down-regulated lipogenic genes and their protein expression levels (fatty acid synthase, stearoyl-CoA desaturase and sterol regulatory element binding protein 1). These results highlight how rumen fluid, plasma, and milk metabolites collectively influence milk fat synthesis, with MA acting as a key regulator of lipid metabolism in mammary epithelial cells. Full article
(This article belongs to the Special Issue Nutrition and Metabolism of Cows and Stress Responses)
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13 pages, 251 KB  
Article
In Vitro Ruminal Fermentation and Gas and Methane Production of Eragrostis curvula Supplemented with Searsia lancea Leaf or Silage Meal
by Morokolo J. Molele, Khanyisile R. Mbatha, Sanele T. Jiyana, Francuois L. Müller and Thamsanqa D. E. Mpanza
Methane 2026, 5(2), 12; https://doi.org/10.3390/methane5020012 - 8 Apr 2026
Viewed by 375
Abstract
Livestock represent a key asset in the livelihood of smallholder farmers and play a critical role in the social dynamics and nutritional security of resource-poor communities. However, within these resource-poor communities, livestock productivity remains low. This is often due to seasonal changes in [...] Read more.
Livestock represent a key asset in the livelihood of smallholder farmers and play a critical role in the social dynamics and nutritional security of resource-poor communities. However, within these resource-poor communities, livestock productivity remains low. This is often due to seasonal changes in the quantity and quality of available feed from the natural veld, which in turn also contributes to methane production. This study aimed to evaluate the effects of supplementing Eragrostis curvula hay with Searsia lancea leaf or silage meal on in vitro fermentation efficiency and gas and methane production. Therefore, an in vitro study using a semi-automated pressure transducer technique was conducted on grass hay alone (control) and grass hay supplemented with 15% or 30% of either S. lancea leaf or silage meal. The dietary treatments were arranged in a complete randomized design, with each treatment replicated four times. Total gas and methane production was recorded at 3, 6, 12, 24 and 48 h using a pressure transducer attached to a data logger. After incubation, samples were collected to determine volatile fatty acids. Supplementing grass hay with 15% S. lancea leaf meal increased gas production by 76%, 52%, 32% and 12% in the first 24 h of incubation. Similarly, increasing the supplementation level to 30% increased gas production by 75%, 63%, 45% and 14%. However, supplementing grass hay with silage meal at 15% significantly reduced gas production by 37% during the first 3 h of incubation, whereas supplementation at 30% had no effect. Supplementing grass hay with S. lancea meals effectively reduced methane production at 24 and 48 h. Grass hay supplemented with 15% or 30% silage meal reduced methane by 46% and 39% at 24 h, while at 48 h, methane was reduced by 39% and 49%, respectively. Supplementing grass hay with S. lancea meals, however, did not affect volatile fatty acids. In conclusion, S. lancea can be strategically used as a supplementary feed source to modulate the rumen ecosystem by attenuating enteric methane production. Further studies are required to determine the effect of S. lancea on rumen microbial composition and its metabolic function. Full article
14 pages, 330 KB  
Article
Characterization of Nigella sativa Meal (NSM) and the Effects on In Vitro Rumen Fermentation and Degradability
by Karina Natasya Juandita, Diky Ramdani, Iman Hernaman, Abdul Shakoor Chaudhry, Sukarman and Ki Ageng Sarwono
Animals 2026, 16(7), 1091; https://doi.org/10.3390/ani16071091 - 2 Apr 2026
Viewed by 428
Abstract
Nigella sativa meal (NSM) is a by-product of the oil extraction process with potential use as a functional feed ingredient in ruminant nutrition due to its rich bioactive compounds and nutrient content. Therefore, this replicated (n = 6) completely randomized design (CRD) [...] Read more.
Nigella sativa meal (NSM) is a by-product of the oil extraction process with potential use as a functional feed ingredient in ruminant nutrition due to its rich bioactive compounds and nutrient content. Therefore, this replicated (n = 6) completely randomized design (CRD) study aimed to firstly characterize NSM for its the bioactive compounds by chromatography–mass spectrometry (GC–MS) and liquid chromatography–MS (LC–MS). The effects of its dietary inclusion at 0%, 5%, 7.5%, and 10% NSM on in vitro rumen fermentation, gas production, CH4 production, and rumen degradability were analyzed. Rumen fluid was collected orally from five sheep (body weight 20 ± 2 kg/head) and incubated with basal diets supplemented with pre-determined levels of NSM. The identified bioactive compounds identified included palmitic acid, oleic acid, linoleic acid, phenolic, flavonoid, thymoquinone, and saponin. The results showed that the dietary NSM supplementation in the diet significantly increased (p < 0.05) gas production at 18 and 48 h, NH3–N concentration, IVDMD (In vitro dry matter degradability), and IVOMD (In vitro organic matter degradability). However, there was no significant effect (p > 0.05) on gas production at 12 and 24 h, and CH4 production, pH, acetate, propionate, iso-butyrate, butyrate, iso-valerate, valerate, the acetate-to-propionate ratio (A:P), or total VFA concentration. Rumen fermentation was optimally modulated up to 10% without adverse effects on digestibility or CH4 production. In this context, NSM acted as a functional feed ingredient in vitro. Therefore, in vivo analyses are required to confirm the efficacy under practical feeding conditions. Full article
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12 pages, 264 KB  
Article
Effect of Variations in the Gas Outlet Location on an In Vitro Rumen Simulation Technique (RUSITEC®) System
by Luiza N. C. Silva, Isabela F. Carrari, Ícaro R. R. Castro, Giulia B. C. Leite, Amanda M. Cezar, Eduardo M. Paula and Marcos I. Marcondes
Fermentation 2026, 12(4), 180; https://doi.org/10.3390/fermentation12040180 - 1 Apr 2026
Viewed by 548
Abstract
The rumen simulation technique (RUSITEC®) is a known model for research in rumen microbiology and fermentation. However, our research group observed inconsistencies in gas production across trials. This study investigated the effects of different gas outlet locations on digestibility, ruminal fermentation, [...] Read more.
The rumen simulation technique (RUSITEC®) is a known model for research in rumen microbiology and fermentation. However, our research group observed inconsistencies in gas production across trials. This study investigated the effects of different gas outlet locations on digestibility, ruminal fermentation, gas production, and microbial protein synthesis. Fifteen fermenters tested three different gas outlet locations within the RUSITEC® equipment: (1) gas outlet directly on the effluent vessel for output liquid (EV); (2) gas outlet directly on fermenter cap (F); and (3) gas outlet on both effluent vessel and fermenter cap (EVF). Data were analyzed using a completely randomized design in SAS (v. 9.4) with the MIXED procedure, and significance was set at p < 0.10. Results showed that altering the gas outlet location did not affect nutrient digestibility (p > 0.10), microbial protein synthesis (p > 0.10), and volatile fatty acid (VFA) production when expressed on a molar basis (p > 0.10). However, total gas production (p = 0.108) was higher in the EVF group and ammonia nitrogen produced in the fermenter was higher in group F (p = 0.081). Furthermore, methane (CH4) production was underestimated when the gas outlet location was in just one of the locations when compared to the EVF group (p = 0.006). VFA proportion was also affected, with lower acetate (p = 0.005) and higher butyrate (p = 0.014) for group EV. These results indicate that the location of the gas outlet is an important methodological factor affecting fermentation measurements in the RUSITEC system, with outlets positioned in both the effluent and fermenter vessels enhancing gas recovery. Full article
13 pages, 502 KB  
Article
Effects of Inoculating Lignin-Degrading Bacteria Isolated from Ruminant Rectum on In Vitro Rumen Diet Degradation
by Chatchai Kaewpila, Pongsatorn Gunun, Nikom Srikacha, Chanon Suntara and Waroon Khota
Fermentation 2026, 12(4), 179; https://doi.org/10.3390/fermentation12040179 - 1 Apr 2026
Viewed by 548
Abstract
In ruminant nutrition, the lignocellulosic complex is a primary constraint limiting the utilization of dietary fiber. The objective of this study was to evaluate the effects of inoculating lignin-degrading bacteria (LDB) isolated from the ruminant rectum on in vitro rumen fermentation characteristics. Rectal [...] Read more.
In ruminant nutrition, the lignocellulosic complex is a primary constraint limiting the utilization of dietary fiber. The objective of this study was to evaluate the effects of inoculating lignin-degrading bacteria (LDB) isolated from the ruminant rectum on in vitro rumen fermentation characteristics. Rectal fecal samples were collected from healthy beef cattle, dairy cattle, buffaloes, and goats (n = 4 per species) using the grab sampling technique. Twenty-eight bacterial colonies were isolated through enrichment and screening on media containing sodium lignosulfonate. Lignin degradation efficiency was assessed spectrophotometrically, while laccase activity was determined using a 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) oxidation assay. Seven isolates exhibiting ligninolytic activity (1.4–5.6% degradation efficiency) were selected to evaluate their effects on in vitro rumen fermentation using a completely randomized design with four replicates. LDB treatments were standardized to a concentration of 2.4 × 105 colony-forming units/mL of rumen fluid medium, while the control received an equal volume of a 0.85% sterile NaCl solution. A rice straw-based total mixed ration served as the substrate, with rumen fluid collected from beef cattle. All treatments were incubated for 48 h. Notably, isolate BC3 consistently enhanced in vitro dry matter digestibility (23.1%), total gas production (18.6%), and total volatile fatty acid concentrations (13.2%) relative to the control and other LDB isolates (p < 0.01). All seven LDB isolates were identified as Gram-negative, rod-shaped, facultative anaerobic bacteria that exhibit catalase activity and tolerate moderately acidic conditions. Phylogenetic tree analysis based on 16S rRNA gene sequencing identified isolate BC3 as being closely related to Escherichia coli strains. These findings demonstrate that the ruminant hindgut is a promising source of LDB with the functional potential to enhance feed digestibility and fermentation end-products in the rumen. Future research should prioritize in vivo trials to evaluate the safety and efficacy of LDB as a direct-fed microbial, specifically focusing on its impact on animal performance and health. Full article
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11 pages, 226 KB  
Article
Effects of Codium fragile Extract Additive on In Vitro and In Vivo Methane Production and Fermentation Characteristics of Korean Native Steers (Hanwoo)
by Seong-Shin Lee, Seong-Uk Jo, Hyun Sang Kim, Ma-Ro Lee, Su-Hyun An and Hwan-Ku Kang
Fermentation 2026, 12(4), 175; https://doi.org/10.3390/fermentation12040175 - 31 Mar 2026
Viewed by 561
Abstract
The present study was conducted to demonstrate the effects of Codium fragile extract on methane production using in vitro and in vivo experiments. An in vitro batch experiment was conducted to evaluate different inclusion levels of Codium fragile extract (0, 0.25, and 0.5% [...] Read more.
The present study was conducted to demonstrate the effects of Codium fragile extract on methane production using in vitro and in vivo experiments. An in vitro batch experiment was conducted to evaluate different inclusion levels of Codium fragile extract (0, 0.25, and 0.5% of substrate dry matter). Methane production significantly decreased in the 0.5% treatment (p < 0.05), whereas dry matter digestibility and total volatile fatty acid concentration were not significantly affected (p > 0.05). Based on the in vitro results, an in vivo feeding experiment was conducted using a 0.5% inclusion level of Codium fragile extract on Hanwoo steers. Methane emissions were significantly decreased by approximately 10% in steers fed Codium fragile extract (p < 0.05). In contrast, rumen fermentation characteristics, feed intake, average daily gain, and blood parameters were not significantly different between the treatments (p > 0.05). These results demonstrate that a dietary additive with 0.5% Codium fragile extract effectively reduced methane emissions without negatively affecting rumen fermentation and growth performance in Hanwoo steers. Full article
(This article belongs to the Special Issue Research Progress of Rumen Fermentation, 2nd Edition)
17 pages, 517 KB  
Article
Effects of L-Valine Supplementation in Low-Nitrogen Diets on Rumen Fermentation Parameters, Predicted Methane Emissions Production, and Microbial Communities In Vitro
by Chuang Li, Yang Liu, Tianao Yang, Zhanyuan Chen, Guotuo Jiang, Kailun Yang and Mengzhi Wang
Animals 2026, 16(7), 1049; https://doi.org/10.3390/ani16071049 - 30 Mar 2026
Viewed by 388
Abstract
Few studies have investigated the effects of L-valine (L-Val) supplementation on in vitro rumen fermentation parameters and methane (CH4) production in low-nitrogen diets for ruminants. Therefore, we examined the impact of L-Val supplementation in low-protein diets on in vitro rumen fermentation [...] Read more.
Few studies have investigated the effects of L-valine (L-Val) supplementation on in vitro rumen fermentation parameters and methane (CH4) production in low-nitrogen diets for ruminants. Therefore, we examined the impact of L-Val supplementation in low-protein diets on in vitro rumen fermentation parameters, CH4 production, and microbial community structure. Two crude protein (CP) levels and 4 L-Val levels were tested as follows: CON group (Control group with 14.05% CP), LD group (low-nitrogen diets with 11.26% CP), LVA group (LD group + 0.25% L-Val), LVB group (LD group + 0.5% L-Val), LVC group (LD group + 0.75% L-Val), and LVD group (LD group + 1% L-Val). The experiment was conducted at five time points (2 h, 4 h, 8 h, 12 h, 24 h), with three replicates per treatment at each time point. Results indicated the following: (1) Fermentation pH decreased overall with time; at each time point, the LVB group exhibited the highest pH, significantly higher than the LD, LVC, and LVD groups (p < 0.05). (2) Ammonia nitrogen (NH3-N) concentration increased over time, with LVA~LVD groups showing higher levels than the LD group at 24 h, while showing no difference compared to the CON group (p > 0.05). (3) Microbial protein (MCP) trends aligned with NH3-N, with the LVB group exhibiting higher MCP than the LD group, while showing no difference compared to the CON group (p > 0.05). (4) Compared to the LD group, adding 0.5~1% L-Val increased acetic acid, total VFA (TVFA), and isobutyric acid concentrations at 4 h, 8 h, and 24 h fermentation (p < 0.05). (5) The LVB group exhibited higher proportions of protozoa and Fibrobacter succinogenes (F. succinogenes) compared to the LD group (p < 0.05). The proportion of F. succinogenes showed no significant difference from the CON group (p > 0.05), while the proportion of Butyrivibrio fibrisolvens (B. fibrisolvens) decreased when L-Val addition exceeded 0.5%. (6) Correlation analysis revealed positive correlation between protozoa and TVFA (R = 0.512, p = 0.030). Isobutyric acid showed positive correlations with protozoa, B. fibrisolvens, and F. succinogenes (p < 0.05). In summary, under the present experimental conditions, the addition of 0.5% L-Val to a low-nitrogen diet did not affect predicted CH4 production, but improved other in vitro rumen fermentation parameters, including acetate, isobutyrate and MCP. Meanwhile, it favored the growth and proliferation of the fibrolytic bacteria (B. fibrisolvens and F. succinogenes). This provides a theoretical basis for the rational formulation of low-nitrogen diets for sheep. Full article
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20 pages, 1730 KB  
Article
In Vitro Evaluation of Spearmint Essential Oil (Mentha spicata L.) Supplementation on Gas Production, Rumen Fermentation, and Microbial Community Structure
by Chengzhen Huang, Jiamin Chen, Lin Wang, Lei Wang, Jiayi Li and Lifeng Dong
Animals 2026, 16(7), 1007; https://doi.org/10.3390/ani16071007 - 25 Mar 2026
Viewed by 454
Abstract
Reducing enteric methane emissions from ruminants has emerged as a critical environmental priority in the face of global climate change, given the substantial contribution of methane to agricultural greenhouse gas outputs. This study evaluated the potential of spearmint essential oil (SEO) to reduce [...] Read more.
Reducing enteric methane emissions from ruminants has emerged as a critical environmental priority in the face of global climate change, given the substantial contribution of methane to agricultural greenhouse gas outputs. This study evaluated the potential of spearmint essential oil (SEO) to reduce methane production and enhance energy utilization efficiency using an in vitro rumen fermentation system. The experiment comprised a control (CON, no additive), three SEO doses (L-SEO: 100 mg/L; M-SEO: 200 mg/L; H-SEO: 400 mg/L), and a commercial essential oil blend (AGL: 150 mg/L). Results indicated that M-SEO and H-SEO significantly reduced methane production at 24 h from 58.11 mL/g DM in CON to 47.93 and 46.58 mL/g DM, respectively (p < 0.001), corresponding to reductions of 17.5% and 19.8%. Furthermore, M-SEO increased total volatile fatty acid concentration from 48.41 to 58.10 mmol/L and elevated the molar proportion of propionate, while significantly enhancing microbial crude protein production (p < 0.001). Microbial community analysis revealed that M-SEO increased bacterial alpha-diversity (Shannon index) (p = 0.001) and significantly enriched specific functional guilds, particularly the propionate-producing genus Succiniclasticum and the butyrate-producing genus Butyrivibrio. Interestingly, the abundance of dominant methanogens (Methanobrevibacter) was not reduced, suggesting a metabolic inhibition mechanism rather than a biocidal effect. Functional prediction analysis further supported this, indicating a downregulation of pathways associated with methanogenesis, including key enzymes such as methyl-coenzyme M reductase. In conclusion, SEO supplementation at 200 mg/L effectively reduced methane production by redirecting metabolic hydrogen toward propionate formation, without affecting overall fermentation. Therefore, the current study indicated that SEO could serve as a sustainable feed additive for mitigating enteric methane emissions in ruminants. Full article
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16 pages, 275 KB  
Article
The Mitigation of Methane Emissions from Ruminants: Evaluating the Efficacy of Selected Additives and Feed Replacements in an In Vitro Trial
by Ana Maria da Costa Goncalves Noronha, Eslam Ahmed, Ahmed O. Matti-Alapafuja, Belgutei Batbekh, Masaaki Hanada, Naoki Fukuma and Takehiro Nishida
Dairy 2026, 7(2), 25; https://doi.org/10.3390/dairy7020025 - 23 Mar 2026
Viewed by 568
Abstract
The need for new feed ingredients that could reduce methane (CH4) emissions from dairy cattle while maintaining rumen function is essential for sustainable milk production. This study aimed to evaluate the CH4 mitigation potential of selected microalgae and macroalgae, along [...] Read more.
The need for new feed ingredients that could reduce methane (CH4) emissions from dairy cattle while maintaining rumen function is essential for sustainable milk production. This study aimed to evaluate the CH4 mitigation potential of selected microalgae and macroalgae, along with an agro-industrial by-product, using two feeding strategies, and hypothesized that lipid- and polyphenol-rich materials would reduce CH4 production in an inclusion-dependent manner. An in vitro batch culture study (24 h) was conducted to evaluate microalgae (Euglena gracilis and Aurantiochytrium spp.), macroalgae (Undaria pinnatifida), and an agro-industrial by-product (grape marc) either as feed additives (5%) or as a partial replacement of the concentrate mixture (30%, 50%, and 70%) in a basal diet consisting of 50% Klein grass hay and 50% concentrate mixture. As a feed additive, grape marc stands out for its potential to reduce CH4 yield by about 43.3% without adversely affecting digestibility, pH, or total volatile fatty acid concentrations. When used as feed replacements, Euglena-, Aurantiochytrium-, and grape marc-based feeds reduced CH4 yield at the highest replacement levels (50 and 70%); however, these effects were accompanied by decreased total gas production and volatile fatty acid concentrations, indicating reduced fermentation activity. Meanwhile, at a 30% replacement level, they showed promising efficiency as alternative feeds. Overall, CH4 mitigation depends more strongly on inclusion strategy rather than feed type. Lipid-rich microalgae showed potential as concentrate replacements up to 30%, whereas grape marc was most effective as a feed additive for reducing CH4 emissions. Full article
(This article belongs to the Section Dairy Animal Nutrition and Welfare)
15 pages, 1951 KB  
Article
Effects of Isoacid Supplementation on In Vitro Rumen Fermentation, Nutrient Degradability and Bacterial Community Diversity Using Corn Silage–Highland Barley Straw as Substrates in Yaks
by Can Luo, Fei Jiang, Anyi Zhong, Xinjue He, Xi Liu, Yanling Huang and Yanhua Gao
Microorganisms 2026, 14(3), 692; https://doi.org/10.3390/microorganisms14030692 - 19 Mar 2026
Viewed by 437
Abstract
This study investigated the effects of isoacid supplementation on in vitro rumen fermentation characteristics, nutrient degradability, and bacterial community diversity in yaks using corn silage–highland barley straw-based substrates. An in vitro fermentation experiment was conducted with a substrate consisting of 80% whole-plant corn [...] Read more.
This study investigated the effects of isoacid supplementation on in vitro rumen fermentation characteristics, nutrient degradability, and bacterial community diversity in yaks using corn silage–highland barley straw-based substrates. An in vitro fermentation experiment was conducted with a substrate consisting of 80% whole-plant corn silage and 20% highland barley straw. Treatments included a control (without isoacids) and four isoacid supplemental levels (0.1%, 0.2%, 0.3%, and 0.4% of substrate dry matter, DM), each with six replicates. A 72 h in vitro gas production experiment was performed to measure cumulative gas production, fermentation parameters, nutrient degradability, and bacterial community diversity. Cumulative gas production increased by 12.96% with 0.2% isoacid supplementation compared to the control (p < 0.05). The contents of microbial protein (MCP), acetate, propionate, and total volatile fatty acids (TVFA) exhibited quadratic responses to the increasing isoacid dosage (p < 0.05). Specifically, MCP content reached a maximum of 0.76 mg/mL with 0.2% isoacids, representing a 31.03% increase compared to the control (p < 0.05). TVFA content was highest (146.85 mmoL/L) at 0.2% isoacid supplementation, with a 16.40% increase compared to the control (p < 0.05). Acetate content increased by 17.99% (p < 0.05), while propionate tended to increase with 0.2% isoacid supplementation (p = 0.08). Supplementation with 0.2% and 0.4% isoacids did not alter the bacterial composition and diversity (p > 0.05). However, at the genus level, g_Ruminococcus, g__Elusimicrobium, g_norank_f_Atopobiaceae, g_norank_o_Coriobacteriales, and g_Romboutsia were identified as differential biomarkers showing significant responses to isoacid supplementation (p < 0.05). Mantel-test analysis revealed positive correlation between g_Ruminococcus abundance and NH3-N content (r < 0.4, p < 0.05); g_Romboutsia abundance and acetate content (r < 0.40, p < 0.05); g_Defluviitaleaceae_UCG-011 abundance and both NH3-N content and the pH of rumen fluid (r < 0.40, p < 0.05); g_norank_o_Coriobacteriales abundance and rumen pH (r < 0.40, p < 0.01). Supplementation with 0.2% isoacids to corn silage–barley straw substrates improved in vitro rumen fermentation characteristics in yaks, which was associated with altered abundances of key bacterial genera including g_Ruminococcus, g__Elusimicrobium, g_norank_f_Atopobiaceae, g_norank_o_Coriobacteriales. Full article
(This article belongs to the Section Veterinary Microbiology)
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27 pages, 942 KB  
Article
Effects of Protein Supplementation and Microbial Inoculation on Fermentation Quality, Aerobic Stability, and In Vitro Digestibility of Maize Silage
by Michael Vuma, Moses M. Ratsaka, Julius T. Tjelele, Thomas Langa, Bhutikini D. Nkosi and Ingrid M. M. Malebana
Fermentation 2026, 12(3), 155; https://doi.org/10.3390/fermentation12030155 - 16 Mar 2026
Viewed by 706
Abstract
The study evaluated the effects of replacing soybean meal (SBM) with marula oilcake (MOC) at equal inclusion (10% fresh weight) levels in whole-crop maize silage treated with or without lactic acid bacteria inoculants on fermentation characteristics, nutritive value, aerobic stability, and in vitro [...] Read more.
The study evaluated the effects of replacing soybean meal (SBM) with marula oilcake (MOC) at equal inclusion (10% fresh weight) levels in whole-crop maize silage treated with or without lactic acid bacteria inoculants on fermentation characteristics, nutritive value, aerobic stability, and in vitro nutrient degradability. Maize was ensiled with SBM or MOC in a non-iso-nitrogenous 2 × 3 factorial design and either inoculated or uninoculated with Lalsil Fresh or Sil-All 4×4 for 90 days. Protein sources differed significantly (p < 0.05). The MOC showed high DM, EE, GE, and ADL, whereas SBM had high CP, ash, and IVOMD. Fibre fractions (aNDF and ADF) were similar (p > 0.05). The SBM control showed significantly high (p < 0.05) LA, NH3-N, CP, IVOMD, propionic acid, and early gas production, indicating efficient fermentation. The SBM + Lalsil maintained low pH, and early OM, CP, and GE degradability. The SBM + Sil-All achieved the highest (p < 0.05) OM, NDF, and ADF degradability and acetic acid production than other treatments. The MOC control showed low (p < 0.05) pH, high fibre and GE, reduced butyric acid, and low 48 h gas production, indicating slower fermentation but improved stability. The MOC + Lalsil had high (p < 0.05) DM, low CO2 and yeasts and moulds, and the highest (p < 0.05) CP degradability, propionic acid, and peak gas production at 12 h. The MOC + Sil-All showed high (p < 0.05) GE and WSC with peak GE degradation at 12 h, but low NDF degradability and reduced gas production. Overall, SBM improved degradability and fermentation efficiency, particularly with Sil-All, whereas MOC enhanced energy density and aerobic stability, with Lalsil optimising protein utilisation. Matching inoculant type to protein source is essential to optimise silage quality and rumen fermentation. Further research should assess different inoculant inclusion rates and include a maize-only control, and evaluate protein source inclusion under iso-nitrogenous conditions to allow more accurate comparisons. Full article
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