Changes in Carbohydrate Composition in Fermented Total Mixed Ration and Its Effects on in vitro Methane Production and Microbiome

Response of rumen methane production and microbial community to different abatement strategies in yaks

BACKGROUND

Developing region-specific dietary strategies is crucial for mitigating methane (CH4) emissions from yaks. However, there is a lack of tailored emission reduction strategies for yak production in the Qinghai-Tibet Plateau region. This study utilizes an in vitro rumen fermentation technique (Based on the ANKOMRF gas production measurement system) to investigate the effects of different dietary interventions on CH4 production from regional yaks. The selected strategies-Sodium Nitrate solution, regional Medicago sativa L., and regional Helianthus tuberosus L.-were chosen for their potential to reduce CH4 production through various mechanisms: Sodium Nitrate as a methanogenesis inhibitor, Medicago sativa L. for its high nutritional value and its ability to modulate microbial fermentation, and Helianthus tuberosus L. due to its inulin content, which promotes beneficial microbial activity. These dietary interventions aim not only to reduce CH4 production but also to support rumen health and productivity. In addition, gas chromatography and microbial sequencing techniques were employed to identify the optimal emission reduction strategy for regional yaks and to elucidate the key factors influencing the efficacy of these strategies.

RESULTS

The results indicate that supplementing the confined feeding ration (FR group) with Sodium Nitrate (12 mmol/L, FRN group), Medicago sativa L. (25%, FRM group), and Helianthus tuberosus L. (3%, FRH group) all have the effect of reducing CH4 production from yak rumen. Among these interventions, the FRM group exhibits the most significant reduction, with a decrease in rumen CH4 production by 42.76% compared to the FR group. The dry matter digestibility, total volatile fatty acids (TVFA), propionate, and butyrate levels in all groups were higher than those in the FR group. However, only the FRM group reached a significant level (P < 0.01). The pH values were significantly lower than those in the FR group (P < 0.01) across all groups. Each group exhibited distinct clustering patterns in bacterial and archaeal communities compared to the FR group (P < 0.05). The α diversity of bacterial communities was significantly lower than that of the FR group (P < 0.01), while the α diversity of archaeal communities was significantly higher than that of the FR group (P < 0.01). Taxa such as Lachnospiraceae, Clostridium, Treponema, Methanomicrobiaceae, Methanosphaera, and Methanoplanus were enriched in the FR group.

CONCLUSIONS

CH4 production from yak rumen were significantly negatively correlated with substrate crude protein (CP) levels, fermentation fluid TVFA levels, α diversity of archaeal communities, and the relative abundance of Selenomonas and Megasphaera in bacterial communities (P < 0.01). Conversely, CH4 production were significantly positively correlated with the relative abundance of Methanoplanus in archaeal communities (P < 0.01). From the perspective of CH4 gas production, the ranking of emission reduction effectiveness for different mitigation strategies is as follows: FRM group > FRH group > FRN group.

Effects of corn straw-based fermented total mixed rations supplemented with exogenous cellulase on growth performance, digestibility, and rumen fermentation in growing beef cattle

OBJECTIVE

This study aimed to assess the impact of corn straw-based unfermented and fermented total mixed rations (TMR) supplemented with exogenous cellulase on the in vitro fermentation characteristics, growth performance, feeding behavior, apparent digestibility, rumen fermentation and digestive enzyme activities of Chinese Simmental bulls.

METHODS

Unfermented (direct spraying of exogenous cellulase onto TMR, TMR) and fermented (exogenous cellulase fermentation for more than 7 d, fermented total mixed rations [FTMR]) TMR were collected, dried, powdered and used as fermentation substrates. The fermentation liquid was ruminal fluid collected from Chinese Simmental bulls. The artificial rumen culture fluid were continuously cultured in vitro for 48 h. Based on the diets they were fed, 24 healthy Chinese Simmental bulls (average weight of 495.93±10.89 kg) were randomly divided into two groups, with 12 bulls in each group, which were fed TMR or FTMR. The study lasted 56 d.

RESULTS

In in vitro experiments, the neutral detergent fiber (NDF) degradability and total volatile fatty acid, propionate, iso-butyrate, iso-valerate and valerate concentrations were greater in the FTMR group (p<0.05) than in the TMR group. However, the methane production, pH and acetate/propionate (A/P) of the FTMR group tended to be lower (p<0.05) than those of the TMR group. In the in vivo experiments, the average daily gain, eating rate, and feed efficiency of the FTMR groups were greater (p<0.05) than those of the TMR group. Similarly, the NDF degradability of the FTMR group was greater (p<0.05) than that of the TMR group. Compared to those in the TMR group, the concentrations of total volatile fatty acids, iso-butyrate, propionate and butyrate were greater in the FTMR group (p<0.05), and the A/P ratio was lower (p<0.05). Similarly, cellulase, xylanase, and β-glucosidase activities were greater (p<0.05) in the FTMR group than in the TMR group.

CONCLUSION

Corn straw-based FTMR supplemented with exogenous cellulase play a vital role in decreasing the structural carbohydrate content of TMR and ruminal methane production in vitro, improving nutrient digestion and absorption, optimizing rumen fermentation, and improving the growth performance of beef cattle.

Oat Brewery Waste Decreased Methane Production and Alters Rumen Fermentation, Microbiota Composition, and CAZymes Profiles

The transformation of oat brewery waste (OBW) into livestock feed could be a potential replacement for the expensive concentrate and one of the effective approaches for avoiding health hazards due to the accumulation of oat brewery waste in the environment. To explore the potential of OBW as a methane (CH4) mitigating agent, an in vitro study was undertaken to investigate the effect of graded replacement of concentrate with OBW on CH4 production, microbiota, feed fermentation, and CAZymes. A total of five treatments with variable proportions of OBW were formulated. The results indicated a linear decrease in the total gas production and a 38-52% decrease in CH4 production with a 60 and 100% replacement of concentrate with OBW. The inclusion of OBW also affected the abundance of microbes such as Firmicutes, Euryarchaeota, Methanobrevibacter, and protozoa numbers. This study demonstrated that OBW can partially replace the concentrate and effectively mitigate CH4 production; however, the concurrent decrease in fermentation cautioned for the partial replacement of concentrate with OBW at an appropriate level at which the fermentation remains unaffected while decreasing CH4 production. Therefore, waste from oat breweries can contribute to curtailing the accumulation of greenhouse gases (GHGs) in the atmosphere.

Sustainable production of extracellular polymeric substances and iron or copper complex from glutinous rice processing wastewater

Essential trace minerals play vital roles in maintaining human and animal health. However, an overdose of the existing inorganic trace minerals is prone to induce detrimental effects that outweigh positive benefits. In this study, an extracellular polymeric substances (EPS)-producing bacterium, identified as Bacillus licheniformis CCTCC M2020298, was isolated from marine using glutinous rice processing wastewater as enrichment medium. The EPS yield of Bacillus licheniformis CCTCC M2020298 could reach 8.62 g/L by using glutinous rice-processing wastewater containing medium. Furthermore, the potential of the EPS as a carrier for synthesizing EPS-iron (Fe) and EPS-copper (Cu) complex was explored. The results showed that the optimum condition for the synthesis EPS-Fe were the reaction temperature 70°C, pH 8.5–9.0 and mass ratio of EPS to trisodium citrate 2:1. The iron content of EPS-Fe reached 77.4 mg/g. Under the same condition, the copper content of EPS-Cu reached 90.7 mg/g. The elemental composition, functional groups and valence state of the mineral elements of EPS-Fe and EPS-Cu were well characterized. The EPS-Fe and EPS-Cu exhibited antioxidant activity in scavenging ·OH, DPPH and ·O2− free radicals, thereby leading to reduced oxidative stress and apoptosis levels in human colonic epithelial cells in vitro. They also inhibited the proliferation of mouse hepatocellular carcinoma H22 and the growth of intestinal pathogens in vitro. This study provided an effective avenue for EPS production from glutinous rice processing wastewater and proved the potential of EPS-Fe and EPS-Cu complexes as a new-type comprehensive essential trace mineral supplement.

Development of an Alternative In Vitro Rumen Fermentation Prediction Model

The aim of this study is to identify an alternative approach for simulating the in vitro fermentation and quantifying the production of rumen methane and rumen acetic acid during the rumen fermentation process with different total mixed rations. In this experiment, dietary nutrient compositions (neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), and dry matter (DM)) were selected as input parameters to establish three prediction models for rumen fermentation parameters (methane and acetic acid): an artificial neural network model, a genetic algorithm-bp model, and a support vector machine model. The research findings show that the three models had similar simulation results that aligned with the measured data trends (R2 ≥ 0.83). Additionally, the root mean square errors (RMSEs) were ≤1.85 mL/g in the rumen methane model and ≤2.248 mmol/L in the rumen acetic acid model. Finally, this study also demonstrates the models' capacity for generalization through an independent verification experiment, as they effectively predicted outcomes even when significant trial factors were manipulated. These results suggest that machine learning-based in vitro rumen models can serve as a valuable tool for quantifying rumen fermentation parameters, guiding the optimization of dietary structures for dairy cows, rapidly screening methane-reducing feed options, and enhancing feeding efficiency.

Effects of different forage proportions in fermented total mixed ration on muscle fatty acid profile and rumen microbiota in lambs

Objective

The objectives of this study were to evaluate the effects of different forage proportions in the fermented total mixed ration (FTMR) on growth performance, muscle fatty acid profile, and rumen microbiota of lambs.

Methods

Thirty 6-month-old small tail Han sheep × Ujumqin lambs with initial body weight (BW) of 27.8 ± 0.90 kg were selected for the test and divided into two groups of 15 sheep in each treatment (three pens per treatment and five lambs per pen) according to the principle of homogeneity. Two isoenergetic and isonitrogenous diets were formulated according to the NRC. The diet treatments were designed as (1) OH treatment containing 25% alfalfa hay and 35% oat hay, and (2) AH treatment containing 35% alfalfa hay with 25% oat hay. The forage-to-concentrate ratio for both diets was 65: 35 (DM basis). Three replicates were randomly selected from each treatment to determine growth performance, fatty acid profile and rumen bacterial communities in lambs.

Results

Results revealed no statistically significant (p > 0.05) differences in dry matter intake and average daily gain between the two diet groups. Cholesterol and intramuscular fat were significantly (p > 0.05) higher in the AH group, while no statistically significant difference (p > 0.05) was found in pH24 value. The muscle fatty acid compositions of lambs were obviously (p < 0.05) influenced by the diet treatments. Compared with the OH group, the C16:1, C17:0, and C20:3n6 contents were higher (p < 0.05) in the AH group, whereas the content of C18:1n9c, C20:1, C18:3n3, and C22:6n3 was obviously (p < 0.05) increased in the OH group. The monounsaturated fatty acid (MUFA) contents were significantly higher in the OH group, whereas no significant differences (p > 0.05) were detected in saturated fatty acid (SFA) and polyunsaturated fatty acid (PUFA) contents among the two diet treatments. Bacterial composition was generally separated into two clusters based on principal coordinate analysis, and the OH group had a higher Shannon index. The relative abundance at the genes level of the Rikenellaceae_RC9_gut_group was obviously (p < 0.05) increased in the AH group and the relative abundances of Prevotella_1, Fibrobacter, and Bacteroidales_UCG_001_unclassified were obviously (p < 0.05) enriched in the OH group. Integrated correlation analysis also underscored a possible link between the muscle fatty acid compositions and significantly altered rumen microbiota.

Conclusion

Overall, oat-based roughage in FTMR could promote a beneficial lipid pattern in the Longissimus lumborum muscles of lambs. These findings provide a potential insight into diet effects on fatty acid profile and the rumen microbiome of lambs, which may help make decisions regarding feeding.

Effect of waste mango silage on the in vitro gas production, in situ digestibility, intake, apparent digestibility, and ruminal characteristics in calf diets

Background and Aim: Mexico is the fifth largest producer of mangoes in the world. For the conservation of agro-industrial waste and crop residues, the ensiling technique has shown good results. This study aimed to evaluate the effect of increasing the level of mango silage (86% waste mango and 14% pangola grass hay) in calf diets on in vitro gas production, in situ digestibility, intake, apparent digestibility, and ruminal characteristics. Materials and Methods: The diets contained 0 (T0), 30 (T1), 45 (T2), and 60% (T3) mango silage. The partial (24, 48, and 72 h) and cumulative (72 h) biogas, CH4 production, and degradation were determined in the in vitro evaluation. In situ digestibility and estimators of fermentation kinetics of dry matter (DM) and organic matter (OM) were determined. Intake, apparent nutrient digestibility, and rumen parameters of calves (200 kg) were evaluated in a 4 × 4 Latin square design. Response to increased mango silage was calculated by linear and quadratic orthogonal contrasts. Results: In vitro partial and cumulative biogas production decreased linearly (p < 0.05), and the partial and cumulative CH4 production did not show linear or quadratic contrast (p > 0.05); in vitro DM degradation, in vitro neutral detergent fiber degradation, and in vitro acid detergent fiber degradation showed a linear increase (p < 0.05). In situ dry matter digestibility (DMDis), in situ organic matter digestibility (OMDis), b, a + b, c, and effective digestibility (ED) of DMDis, a, a + b, c, and ED of OMDis increased linearly (p < 0.05). Dry matter intake, OM intake, and crude protein intake showed a linear increase (p < 0.05); NDF intake and ADF intake presented a quadratic behavior (p < 0.05). Apparent digestibility of DM, OM, CP, and hemicellulose, pH, N-NH3, total bacterial count, acetate, propionate, butyrate, volatile fatty acids, acetate: propionate ratio, cellulolytic bacteria, and protozoa did not present a linear or quadratic orthogonal effect (p > 0.05). Conclusion: The in vitro, in situ, and in vivo variables demonstrated that up to 60% mango silage can be used for the intensive fattening of calves in confinement. Keywords: alternative feed, alternative feeding, cattle, silage, tropics.

Rumen Fermentation Parameters Prediction Model for Dairy Cows Using a Stacking Ensemble Learning Method

Volatile fatty acids (VFAs) and methane are the main products of rumen fermentation. Quantitative studies of rumen fermentation parameters can be performed using in vitro techniques and machine learning methods. The currently proposed models suffer from poor generalization ability due to the small number of samples. In this study, a prediction model for rumen fermentation parameters (methane, acetic acid (AA), and propionic acid (PA)) of dairy cows is established using the stacking ensemble learning method and in vitro techniques. Four factors related to the nutrient level of total mixed rations (TMRs) are selected as inputs to the model: neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), and dry matter (DM). The comparison of the prediction results of the stacking model and base learners shows that the stacking ensemble learning method has better prediction results for rumen methane (coefficient of determination (R2) = 0.928, root mean square error (RMSE) = 0.968 mL/g), AA (R2 = 0.888, RMSE = 1.975 mmol/L) and PA (R2 = 0.924, RMSE = 0.74 mmol/L). And the stacking model simulates the variation of methane and VFAs in relation to the dietary fiber content. To demonstrate the robustness of the model in the case of small samples, an independent validation experiment was conducted. The stacking model successfully simulated the transition of rumen fermentation type and the change of methane content under different concentrate-to-forage (C:F) ratios of TMR. These results suggest that the rumen fermentation parameter prediction model can be used as a decision-making basis for the optimization of dairy cow diet compositions, rapid screening of methane emission reduction, feed beneficial to dairy cow health, and improvement of feed utilization.

Effects of Replacing Alfalfa Hay with Oat Hay in Fermented Total Mixed Ration on Growth Performance and Rumen Microbiota in Lambs

The use of the fermented total mixed ration (FTMR) is a promising approach for the preservation of feedstuff, but the effect of FTMR on the between growth performance and ruminal microflora of lambs are still limited. This study aimed to assess the effects of different roughage types in the FTMR on growth performance and rumen microbiota of lambs. Forty-five six-month-old Small tail Han sheep × Ujumqin male lambs were randomly allocated into three groups (three pens per treatment and five lambs per pen) with the initial body weight (BW) of 28.50 ± 1.50 kg. The three treatments were as follows: the low oat percentages group (LO) contained 200 g/kg oat hay + 400 g/kg alfalfa hay, the medium oat percentages group (MO) contained 300 g/kg oat hay + 300 g/kg alfalfa hay, and the high oat percentages group (HO) contained 400 g/kg oat hay + 200 g/kg alfalfa hay. The result revealed that the dry matter intake and average daily gain were markedly (p < 0.05) higher in the MO treatment than in the LO and HO treatments, whereas no significant difference (p > 0.05) was found in the final body weight. There were no significant (p > 0.05) differences on the Shannon and Simpson index among the three treatments. The PCoA score plot illustrated the individual separation in the LO, MO, and HO treatments. At the phylum level, the presence of Bacteroidetes and Firmicutes belonging to the dominant phyla is widely described in rumen communities among the three treatments. The relative abundances of Prevotella, Fibrobacter, and Succinivibrio in the level of the genes were remarkably higher (p < 0.05) in MO treatment than that in LO and HO treatments, while the relative abundance of Sediminispirochaeta was remarkably higher (p < 0.05) in LO treatment than that in MO and HO treatments. These results indicated that the MO treatments could more effectively improve growth performance than the LO and HO treatments, and also revealed that the different forage types in diets reshaped the compositions and function of the rumen microbiota. Consequently, the findings presented in this study provide a reference for the application of FTMR in animal production and the understanding of the interaction between diet, animal performance, and ruminal microbiota.