Search

Introduction: This study examines the optimum conversion of Wuzhishan pig manure by Black Soldier Fly Larvae (BSFL) at various phases of development, as well as the impact of gut microbiota on conversion efficiency. Method and results: In terms of conversion efficiency, BSFL outperformed the growing pig stage (GP) group, with significantly higher survival rates (96.75%), fresh weight (0.23 g), and larval conversion rate (19.96%) compared to the other groups. Notably, the GP group showed significant dry matter reductions (43.27%) and improved feed conversion rates (2.17). Nutritional composition varied, with the GP group having a lower organic carbon content. High throughput 16S rRNA sequencing revealed unique profiles, with the GP group exhibiting an excess of Lactobacillus and Clostridium. Promising cellulose-degrading bacteria in pig manure and BSFL intestines, including Bacillus cereus and Bacillus subtilis, showed superior cellulose degradation capabilities. The synergy of these thermophilic bacteria with BSFL greatly increased conversion efficiency. The BSFL1-10 group demonstrated high growth and conversion efficiency under specific conditions, with remarkable larval moisture content (71.11%), residual moisture content (63.20%), and waste reduction rate (42.28%). Discussion: This study sheds light on the optimal stages for BSFL conversion of pig manure, gut microbiota dynamics, promising thermophilic cellulosedegrading bacteria, and the significant enhancement of efficiency through synergistic interactions. These findings hold great potential for sustainable waste management and efficient biomass conversion, contributing to environmental preservation and resource recovery. [ABSTRACT FROM AUTHOR]

This study explores whether guanidinoacetic acid (GAA) addition can regulate nutrient degradability, rumen fermentation characteristics, and gas composition in two sheep-fattening diets. A 2 × 8 factorial in vitro culture was examined to determine the effects of GAA addition at the following levels of 0%, 0.03%, 0.05%, 0.07%, 0.09%, 0.11%, 0.13%, and 0.15% of two total mixed rations (T1 diet: early fattening stage diet; T2 diet: late fattening stage diet). After 72 h in vitro incubation of two diets with mixed rumen liquid obtained from six rumen-cannulated lambs, the T2 diet exhibited higher dry matter (DM) digestibility, higher cumulative gas production at 72 h (GP72), higher asymptotic gas production(A), and longer the time at which half of A is reached (C). However, it exhibited a lower acetic acid and a lower ratio of acetate to propionate than the diet of T1. A quadratic increase occurred in neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility, with a maximum point occurring at the 0.09% GAA group. The gas production kinetic result indicated that increasing the level of GAA addition resulted mainly in an increase of GP72 and A, with the maximum point occurring at 0.09% for the T1 diet and 0.07–0.09% for the T2 diet. Moreover, the levels of GAA addition did not affect pH, the proportion of any of the volatile acid, or gas composition, but when the levels of GAA addition were increased, the microbial crude protein (MCP), ammonia nitrogen (NH3-N), and total volatile fatty acid (TVFA) content exhibited a quadratic relationship. The highest MCP contents were seen in the 0.07%, 0.09%, and 0.11% groups, while NH3-N and TVFA were in the 0.07% group. In summary, the appropriate level of GAA addition in early and late fattening stage diets ranged from 0.07% to 0.11%. [ABSTRACT FROM AUTHOR]

Direct-fed microbial products (DFM) are probiotics that can be used advantageously in ruminant production. The in vitro gas production technique (IVGPT) is a method to simulate rumen fermentation and can be used to measure degradation, gas production, and products of fermentation of such additives. However, inter-laboratory differences have been reported. Therefore, tests using the same material were used to validate laboratory reproducibility. The objective of this study was to assess the effect of adding two DFM formulations on fermentation kinetics, methane (CH4) production, and feed degradation in two different basal feeds while validating a newly established IVGPT laboratory. Six treatments, with three replicates each, were tested simultaneously at the established IVGPT lab at the University of Copenhagen, and the new IVGPT lab at Chr. Hansen Laboratories. Maize silage (MS) and grass silage (GS) were fermented with and without the following DFM: P1: Ligilactobacillus animalis and Propionibacterium freudenreichii (total 1.5 × 107 CFU/mL), P2: P1 with added Bacillus subtilis and B. licheniformis (total 5.9 × 107 CFU/mL). The DFM were anaerobically incubated in rumen fluid and buffer with freeze-dried silage samples for 48 h. Total gas production (TGP: mL at Standard Temperature and Pressure/gram of organic matter), pH, organic matter degradability (dOM), CH4concentration (MC) and yield (MY), and volatile fatty acid (VFA) production and profiles were measured after fermentation. No significant differences between the laboratories were detected for any response variables. The dOM of MS (78.3%) was significantly less than GS (81.4%), regardless of the DFM added (P1 and P2). There were no significant differences between the effects of the DFM within the feed type. MS produced significantly more gas than GS after 48 h, but GS with DFM produced significantly more gas at 3 and 9 h and a similar gas volume at 12 h. Both DFM increased TGP significantly in GS at 48 h. There was no difference in total VFA production. However, GS with and without probiotics produced significantly more propionic acid and less butyric acid than MS with and without probiotics. Adding P2 numerically reduced the total methane yield by 4–6% in both MS and GS. The fermentation duration of 48 h, used to determine maximum potential dOM, may give misleading results. This study showed that it is possible to standardize the methodology to achieve reproducibility of IVGPT results. Furthermore, the results suggest that the P2 DFM may have the potential to reduce CH4 production without affecting organic matter degradation. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced polymer composites (CFRPs) exhibit additional hazards during and after burning due to respirable fragments of thermo-oxidatively decomposed carbon fibers. In this study, various phosphasilazanes are incorporated into the RTM 6 epoxy matrix of a CFRP to investigate their flame-retarding and fiber-protective properties via cone calorimetry. Residual carbon fibers are analyzed using SEM and EDX regarding their diameter and elemental composition of deposits. The decomposition process of phosphasilazanes is characterized by DIP-MS and infrared spectroscopy of char. Flame-retardant efficiency and mode of action are correlated with the chemical structure of the individual phosphasilazane and compared for neat resin and composite samples. Phosphasilazanes mainly acting in the condensed phase show beneficial fiber-protective and flame-retardant properties. Those with additional gas phase activity are less efficient. The phosphasilazanes degrade thermally via scission of the Si-N bond. The distribution and agglomeration of deposited particles, formed during the fire, influence the residual fiber diameters. Continuous layers show the best combination of flame retardancy and fiber protection, as observed for N-dimethylvinylsilyl-amidophosphorus diphenylester. [ABSTRACT FROM AUTHOR]

ABSTRACT Fibrobacter succinogenes is a cellulolytic bacterium that plays an essential role in the degradation of plant fibers in the rumen ecosystem. It converts cellulose polymers into intracellular glycogen and the fermentation metabolites succinate, acetate, and formate. We developed dynamic models of F. succinogenes S85 metabolism on glucose, cellobiose, and cellulose on the basis of a network reconstruction done with the automatic reconstruction of metabolic model workspace. The reconstruction was based on genome annotation, five template-based orthology methods, gap filling, and manual curation. The metabolic network of F. succinogenes S85 comprises 1,565 reactions with 77% linked to 1,317 genes, 1,586 unique metabolites, and 931 pathways. The network was reduced using the NetRed algorithm and analyzed for the computation of elementary flux modes. A yield analysis was further performed to select a minimal set of macroscopic reactions for each substrate. The accuracy of the models was acceptable in simulating F. succinogenes carbohydrate metabolism with an average coefficient of variation of the root mean squared error of 19%. The resulting models are useful resources for investigating the metabolic capabilities of F. succinogenes S85, including the dynamics of metabolite production. Such an approach is a key step toward the integration of omics microbial information into predictive models of rumen metabolism. IMPORTANCE F. succinogenes S85 is a cellulose-degrading and succinate-producing bacterium. Such functions are central for the rumen ecosystem and are of special interest for several industrial applications. This work illustrates how information of the genome of F. succinogenes can be translated to develop predictive dynamic models of rumen fermentation processes. We expect this approach can be applied to other rumen microbes for producing a model of rumen microbiome that can be used for studying microbial manipulation strategies aimed at enhancing feed utilization and mitigating enteric emissions.

Feeding with a suitable level of milk replacer (MR) can improve the survival rate and stimulate the growth potential of early lambs. However, feeding excessive MR might be detrimental to rumen development and microbial colonization. Herein, we investigated the effects of feeding different levels of MR on rumen digestive function and ruminal microorganisms. Fourteen healthy male Hu lambs with similar birth weights and detailed pedigree records were divided into two groups to receive low (2% of average body weight per day) and high (4% of average body weight per day) levels of MR. We analyzed the effects of the MR feeding level on growth performance, fiber degradation rates, rumen fermentation parameters, enzyme activities and rumen histomorphology. We found that feeding with a high level of MR improved the average daily gain of early lambs, but decreased the starter intake, rumen weight and papillae length. We also analyzed the effects of the MR feeding level on the rumen microbiota using 16S-rRNA amplicon sequencing data. The results showed that high a MR feeding level increased the rumen microbial diversity but decreased the abundance of many carbohydrate degrading bacteria. Several bacterial genera with significant differences correlated positively with rumen cellulase activity and the acid detergent fiber degradation rate. Our results suggested that a high level of MR could improve the growth performance of early lambs in the short term; however, in the long term, it would be detrimental to rumen development and have adverse effects on the adaptation process of the microbiota to solid feed. [ABSTRACT FROM AUTHOR]

Background: Digestibility of fiber in the rumen is not due to enzymatic activity of individual bacteria, but rather to their interaction, which complements their enzymatic functioning. Thus, efficiency of fiber digestion depends on the diversity and density of cellulolytic bacteria. Objective: To estimate in vitro production of biogas, methane, and fermentative characteristics of cobra grass (Brachiaria hibrido) inoculated with ruminal bacteria (RB) in coculture with isolated cellulolytic bacteria (ICB) from bovine (ICBbov) or water buffalo (ICBbuf). Methods: ICBbov and ICBbuf were isolated from ruminal cellulolytic bacteria consortia using specific culture media for cellulolytic bacteria. Both were morphologically characterized and a Gram stain was performed. In the in vitro gas production test, the substrate was cobra grass and the inocula were ruminal bacteria (RB), ICBbov, ICBbuf, Coculturebov (RB + ICBbov) and Coculturebuf (RB + ICBbuf). Biogas and methane (CH4) production, as well as dry matter degradation (DMD) and neutral detergent fiber degradation (NDFD) were measured. A completely randomized design was used. Results: The ICB obtained were Gram positive cocci. Accumulated biogas production at 72 h from ICBbov and ICBbuf was on average 42.11% of that produced by RB. The Coculturebov produced 14.24% more biogas than RB. The CH4 production was lower in ICBbov and ICBbuf than in RB, Coculturebov and Coculturebuf. The DMD and NDFD were not different among RB, Coculturebov and Coculturebuf. The ICBbov degraded 37.10 and 96.34% more DMD and NDFD than ICBbuf (p<0.05). Conclusion: The use of ICB from bovine or water buffalo in coculture with RB does not improve in vitro production of biogas, DMD or NDFD with respect to RB alone. [ABSTRACT FROM AUTHOR]

Fiber digestibility is a key-point of forage usage in ruminant production systems. The present study aimed to evaluate the effect of fibrolytic enzyme blend on whole-plant sorghum silage fermentation profile, fermentative losses, chemical composition, in vitro degradation, and aerobic stability. It used fifty experimental silos (plastic bucket, 28 cm i.d. and 25 cm in height) in a blocked randomized design to evaluate the following fibrolytic enzyme levels: 0, 150, 300, 450, and 600 mL per ton of dry matter (DM). Enzymes had 300 U/mL of xylanase and 300 U/mL of cellulase. Enzymes linearly increased acetic acid, branched-chain organic acids, and ethanol concentration of silage. Although there was no treatment effect on silage DM recovery over the ensiling process, enzyme levels linearly increased gas, effluent, and total losses. Intermediary levels of enzymes (from 312 to 342 mL/ton DM) decreased fiber content (NDF and ADF), whereas improved NFC silage content. Besides, enzymes did not affect DM and NDF degradation and tended to linearly reduce acid detergent fiber in vitro degradation. The enzymes addition linearly decreased silage temperature after aerobic exposure. However, there was no treatment effect on silage pH after aerobic exposure also during the time that silage remained with a temperature lower than 2°C above environmental temperature. Thus, fibrolytic enzymes reduce fiber content, promote a heterolactic fermentation, and reduce silage temperature after aerobic exposure. However, this increases fermentative losses and has no positive effect on in vitro degradation and the time of aerobic stability. [ABSTRACT FROM AUTHOR]

Static quantification measures of chemical components are commonly used to make certain assumptions about forage or feed nutritive value and quality. In order for modern nutrient requirement models to estimate intake and digestibility more accurately, kinetic measures of ruminal fiber degradation are necessary. Compared to in vivo experiments, in vitro (IV) and in situ (IS) experimental techniques are relatively simple and inexpensive methods to determine the extent and rate of ruminal fiber degradation. This paper summarizes limitations of these techniques and statistical analyses of the resulting data, highlights key updates to these techniques in the last 30 yr, and presents opportunities for further improvements to these techniques regarding ruminal fiber degradation. The principle biological component of these techniques, ruminal fluid, is still highly variable because it is influenced by ruminally fistulated animal diet type and timing of feeding, and in the case of the IV technique by collection and transport procedures. Commercialization has contributed to the standardization, mechanization, and automation of the IV true digestibility technique, for example, the well-known DaisyII Incubator. There has been limited commercialization of supplies for the IS technique and several review papers focused on standardization in the last 30 yr; however, the IS experimental technique is not standardized and there remains variation within and among laboratories. Regardless of improved precision resulting from enhancements of these techniques, the accuracy and precision of determining the indigestible fraction are fundamental to modeling digestion kinetics and the use of these estimates in more complex dynamic nutritional modeling. Opportunities for focused research and development are additional commercialization and standardization, methods to improve the precision and accuracy of indigestible fiber fraction, data science applications, and statistical analyses of results, especially for IS data. In situ data is typically fitted to one of a few first-order kinetic models, and parameters are estimated without determining if the selected model has the best fit. Animal experimentation will be fundamental to the future of ruminant nutrition and IV and IS techniques will remain vital to bring together nutritive value with forage quality. It is feasible and important to focus efforts on improving the precision and accuracy of IV and IS results. [ABSTRACT FROM AUTHOR]

Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to obtain a rumen native yeast isolate and investigate its effects on growth performance, nutrient digestibility, rumen fermentation and microbiota in Hu sheep. Yeasts were isolated by picking up colonies from agar plates, and identified by sequencing the ITS sequences. One isolate belonging to Pichia kudriavzevii had the highest optical density among these isolates obtained. This isolate was prepared to perform an animal feeding trial. A randomized block design was used for the animal trial. Sixteen Hu sheep were randomly assigned to the control (CON, fed basal diet, n = 8) and treatment group (LPK, fed basal diet plus P. kudriavzevii, CFU = 8 × 109 head/d, n = 8). Sheep were housed individually and treated for 4 weeks. Compared to CON, LPK increased final body weight, nutrient digestibility and rumen acetate concentration and acetate-to-propionate ratio in sheep. The results of Illumina MiSeq PE 300 sequencing showed that LPK increased the relative abundance of lipolytic bacteria (Anaerovibrio spp. and Pseudomonas spp.) and probiotic bacteria (Faecalibacterium spp. and Bifidobacterium spp.). For rumen eukaryotes, LPK increased the genera associated with fiber degradation, including protozoan Polyplastron and fungus Pichia. Our results discovered that rumen native yeast isolate P. kudriavzevii might promote the digestion of fibers and lipids by modulating specific microbial populations with enhancing acetate-type fermentation. [ABSTRACT FROM AUTHOR]

Background: Digestibility of fiber in the rumen is not due to enzymatic activity of individual bacteria, but rather to their interaction, which complements their enzymatic functioning. Thus, efficiency of fiber digestion depends on the diversity and density of cellulolytic bacteria. Objective: To estimate in vitro production of biogas, methane, and fermentative characteristics of cobra grass (Brachiaria hibrido) inoculated with ruminal bacteria (RB) in coculture with isolated cellulolytic bacteria (ICB) from bovine (ICBbov) or water buffalo (ICBbuf). Methods: ICBbov and ICBbuf were isolated from ruminal cellulolytic bacteria consortia using specific culture media for cellulolytic bacteria. Both were morphologically characterized and a Gram stain was performed. In the in vitro gas production test, the substrate was cobra grass and the inocula were ruminal bacteria (RB), ICBbov, ICBbuf, Coculturebov (RB + ICBbov) and Coculturebuf (RB + ICBbuf). Biogas and methane (CH4) production, as well as dry matter degradation (DMD) and neutral detergent fiber degradation (NDFD) were measured. A completely randomized design was used. Results: The ICB obtained were Gram positive cocci. Accumulated biogas production at 72 h from ICBbov and ICBbuf was on average 42.11% of that produced by RB. The Coculturebov produced 14.24% more biogas than RB. The CH4 production was lower in ICBbov and ICBbuf than in RB, Coculturebov and Coculturebuf. The DMD and NDFD were not different among RB, Coculturebov and Coculturebuf. The ICBbov degraded 37.10 and 96.34% more DMD and NDFD than ICBbuf (p

Twelve Liuyang black goats were selected and divided into three groups in a randomized design and they were provided one of the three treatment diets with different chop lengths of ramie silage [1 cm (RS1), 2 cm (RS2), and 3 cm (RS3)]. The length had no effect on pH or the content of acetic acid, butyric acid, and valeric acid. In contrast, NH3-N decreased (P = 0.024) and the ratio of acetate to propionate (P = 0.083) and total volatile fatty acid (TVFA) content (P = 0.087) tended to decrease, and the proportion of propionic acid tended to increase (P = 0.096) with an increase in the chop length of ramie. The increasing lengths of ramie silage decreased the content of total essential amino acids (AA) (P = 0.001), total non-essential AA (P = 0.003), and total AA (P = 0.001), and decreased the concentration of aspartic acid (P = 0.076) in the ruminal fluid. Ramie silage affected xylanase activity (P = 0.043), with greater activity in RS1 than in RS2 and RS3. The recommended chop length of ramie silage is 1 cm because of increasing TVFA, amino acid concentration, and xylanase activity in the ruminal fluid of goats.

This study explores whether guanidinoacetic acid (GAA) addition can regulate nutrient degradability, rumen fermentation characteristics, and gas composition in two sheep-fattening diets. A 2 × 8 factorial in vitro culture was examined to determine the effects of GAA addition at the following levels of 0%, 0.03%, 0.05%, 0.07%, 0.09%, 0.11%, 0.13%, and 0.15% of two total mixed rations (T1 diet: early fattening stage diet; T2 diet: late fattening stage diet). After 72 h in vitro incubation of two diets with mixed rumen liquid obtained from six rumen-cannulated lambs, the T2 diet exhibited higher dry matter (DM) digestibility, higher cumulative gas production at 72 h (GP72), higher asymptotic gas production(A), and longer the time at which half of A is reached (C). However, it exhibited a lower acetic acid and a lower ratio of acetate to propionate than the diet of T1. A quadratic increase occurred in neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility, with a maximum point occurring at the 0.09% GAA group. The gas production kinetic result indicated that increasing the level of GAA addition resulted mainly in an increase of GP72 and A, with the maximum point occurring at 0.09% for the T1 diet and 0.07–0.09% for the T2 diet. Moreover, the levels of GAA addition did not affect pH, the proportion of any of the volatile acid, or gas composition, but when the levels of GAA addition were increased, the microbial crude protein (MCP), ammonia nitrogen (NH3-N), and total volatile fatty acid (TVFA) content exhibited a quadratic relationship. The highest MCP contents were seen in the 0.07%, 0.09%, and 0.11% groups, while NH3-N and TVFA were in the 0.07% group. In summary, the appropriate level of GAA addition in early and late fattening stage diets ranged from 0.07% to 0.11%.

The main objective of this study is to better understand the performance changes of naturally aged glass fiber-reinforced concrete (GFRC) and polypropylene fiber-reinforced concrete (PPFRC), especially the degradation of fibers, which is of great significance for evaluating the durability of structures using these two types of composite materials. The mechanical properties, water absorption, and microstructures of GFRC and PPFRC at a curing age of three years, including their compressive strength, full curves of water absorption, fiber-matrix interaction, and fiber degradation, were systematically studied, and the related properties were compared with those at the curing age of 28 days. The degradation of fibers after freeze-thaw cycles was also studied. The results revealed the following. The water/binder ratio (w/b) affects the rate of increase of the long-term compressive strength of naturally aged concrete. In general, the water absorption of fiber-reinforced concrete (FRC) at the curing age of three years was found to be significantly reduced, but with the increases of w/b and the fiber content to the maximum values, the water absorption of the specimens cured for three years was higher than that of the specimens cured for 28 days. Moreover, with the increase of the curing age, the optimal glass fiber (GF) contents for reducing the water absorption decreased from 1.35% to 0.90% (w/b = 0.30), and from 0.90% to 0.45% (w/b = 0.35), respectively. The GF surface was degraded into continuous pits with diameters of about 200 to 600 nm, and the surface of the pits was attached with spherical granular C-S-H gel products with diameters of about 30 to 44 nm. The freeze-thaw cycles were found to have no significant effect on the pits on the GF surface and the granular C-S-H gel products attached to the pits, but caused a portion of the cement matrix covering the GF to fall off. The interfacial bonding between the polypropylene fiber (PPF) and the cement matrix exhibited almost no change in the PPFRC after three years of curing as compared with that after 28 days of curing. Furthermore, the cement hydration gel on the PPF surface was not significantly damaged by 150 freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced polymer composites (CFRPs) exhibit additional hazards during and after burning due to respirable fragments of thermo-oxidatively decomposed carbon fibers. In this study, various phosphasilazanes are incorporated into the RTM 6 epoxy matrix of a CFRP to investigate their flame-retarding and fiber-protective properties via cone calorimetry. Residual carbon fibers are analyzed using SEM and EDX regarding their diameter and elemental composition of deposits. The decomposition process of phosphasilazanes is characterized by DIP-MS and infrared spectroscopy of char. Flame-retardant efficiency and mode of action are correlated with the chemical structure of the individual phosphasilazane and compared for neat resin and composite samples. Phosphasilazanes mainly acting in the condensed phase show beneficial fiber-protective and flame-retardant properties. Those with additional gas phase activity are less efficient. The phosphasilazanes degrade thermally via scission of the Si-N bond. The distribution and agglomeration of deposited particles, formed during the fire, influence the residual fiber diameters. Continuous layers show the best combination of flame retardancy and fiber protection, as observed for N-dimethylvinylsilyl-amidophosphorus diphenylester.

The co-digestion of swine manure with vegetable waste is an alternative that can increase the production of biogas and methane generated by the isolated digestion of manure. However, recommendations that are based on the best ratio between manure and forage, as well as the age of harvest, are still scarce in the literature. This study was conducted to evaluate inclusions (0, 25, 50, 75 and 100%) of the total solids (TS) of Elephant grass (Pennisetum purpureum Schum) harvested at two ages medium age (MA) at 45 days of growth and advanced age (AA) at 90 days in co-digestion with swine manure, using an entirely randomized design in a 5x2 factorial scheme. Batch digesters were used and biogas production was monitored for 12 weeks. There was influence of forage age (P <0.05) on the degradation of solids and neutral detergent fiber, with higher values for the substrates containing MA forage. The highest CH4 yields were obtained by the substrates containing MA forage in the inclusion of 27.7 and 31.6%, being 253.7 and 222.2 L of CH4 per Kg of total or volatile solids. The age of the forages influenced the onset and persistence of biogas production, being advantageous only in the inclusion of 25% of MA forage. The AA forage inclusion is not recommended for co-digestion with swine manure. [ABSTRACT FROM AUTHOR]

Bio-fermentation technology has been successfully developed for ensiling rice straw; however, its effects on the particle-attached microbial community remains unknown. Therefore, rice straw (RS) and bio-fermented rice straw (BFRS) were used as substrates for in vitro rumen fermentation to investigate the effect of bio-fermentation on particle-attached microbial community, as well as their effects on gas and methane production, fermentation products, and fiber degradation. Our results have shown that total gas production, fiber degradation, and in vitro fermentation products were significantly higher (p < 0.05) for the BFRS than the RS, while methane concentration in total gas volume was significantly lower (p < 0.05) for the BFRS than RS. Linear discriminant effect size (LefSe) analysis revealed that the relative abundance of the phyla Bacteroidetes, Fibrobacteres, Proteobacteria, and Lantisphaerae, as well as the genera Fibrobacter, Saccharofermentans, and [Eubacterium] ruminantium groups in the tightly attached bacterial community, was significantly higher (p < 0.05) for the BFRS than the RS, whereas other microbial communities did not change. Thus, bio-fermentation altered the tightly attached bacterial community, thereby improving gas production, fiber degradation, and fermentation products. Furthermore, bio-fermentation reduced methane concentration in total gas volume without affecting the archaeal community. [ABSTRACT FROM AUTHOR]

In order to study the potential for efficient fiber degradation by intestinal microorganisms in Diqing Tibetan pigs, we first investigated the dietary structure of Diqing Tibetan pigs in their original habitat, then 60 healthy adult Diqing Tibetan pigs were randomly divided into 2 groups with 6 replicates each and 5 pigs in each replicate. The content of neutral detergent fiber in treatment 1 and 2 were adjusted to 20% and 40%, respectively. The total tract digestibility of nutrients and the degradation efficiency of fecal microorganisms to different types of fiber were determined. Results showed that the composition and nutritional level of Diqing Tibetan pig original diet differed greatly in different seasons. The content of crude fiber in the original diet was as high as 12.3% and the neutral detergent fiber was 32.5% in April, while the content of crude fiber was 4.9% and the neutral detergent fiber was 13.3% in October. With the increase of dietary fiber level, the total tract apparent digestibility of dry matter, crude fiber, crude protein, acid detergent fiber, neutral detergent fiber, ether extract, and organic matter decreased significantly (p < 0.05), and the contents of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid in the feces were also significantly (p < 0.05) reduced. The ability of Diqing Tibetan pig fecal microorganisms to degrade neutral detergent fiber was significantly higher (p < 0.05) than "Duroc × Landrace × Yorkshire" pig. In addition, there was no significant difference (p > 0.05) in the degradation efficiency of the same type of fiber between NDF-20 and NDF-40 groups. Our results strongly suggested that Diqing Tibetan pigs have the potential to efficiently utilize fiber, and their unique intestinal microbial composition is the main reason for their efficient utilization of dietary fiber. [ABSTRACT FROM AUTHOR]

Background: Coffee hulls obtained from dry processing, have the potential to be used in ruminant diets. Objective: To evaluate the chemical composition and in situ degradability of dry matter (DM) and neutral detergent fiber (NDF) of coffee hulls treated with calcium oxide (CaO) in different environmental conditions (EC). Methods: Coffee hulls were subjected to treatments distributed in a 2 × 2 factorial arrangement, consisting of two levels of CaO (0 and 5%, on a DM basis) and two environmental conditions (aerobiosis and anaerobiosis) in a completely randomized design with four replicates, totaling sixteen experimental units. Five-gram samples were incubated in the rumen of two male cattle for 0, 3, 6, 9, 12, 24, 48, 72, 96, and 120 h. Results: Regarding dry matter degradation kinetic parameters, except for fraction b, the potential and effective degradability was affected (p

Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to obtain a rumen native yeast isolate and investigate its effects on growth performance, nutrient digestibility, rumen fermentation and microbiota in Hu sheep. Yeasts were isolated by picking up colonies from agar plates, and identified by sequencing the ITS sequences. One isolate belonging to Pichia kudriavzevii had the highest optical density among these isolates obtained. This isolate was prepared to perform an animal feeding trial. A randomized block design was used for the animal trial. Sixteen Hu sheep were randomly assigned to the control (CON, fed basal diet, n = 8) and treatment group (LPK, fed basal diet plus P. kudriavzevii, CFU = 8 × 109 head/d, n = 8). Sheep were housed individually and treated for 4 weeks. Compared to CON, LPK increased final body weight, nutrient digestibility and rumen acetate concentration and acetate-to-propionate ratio in sheep. The results of Illumina MiSeq PE 300 sequencing showed that LPK increased the relative abundance of lipolytic bacteria (Anaerovibrio spp. and Pseudomonas spp.) and probiotic bacteria (Faecalibacterium spp. and Bifidobacterium spp.). For rumen eukaryotes, LPK increased the genera associated with fiber degradation, including protozoan Polyplastron and fungus Pichia. Our results discovered that rumen native yeast isolate P. kudriavzevii might promote the digestion of fibers and lipids by modulating specific microbial populations with enhancing acetate-type fermentation.

To support improving genetic potential for increased milk production, intake of digestible carbohydrate must also increase to provide digestible energy and microbial protein synthesis. We hypothesized that the provision of exogenous branched-chain volatile fatty acids (BCVFA) would improve both neutral detergent fiber (NDF) degradability and efficiency of microbial protein synthesis. However, BCVFA should be more beneficial with increasing efficiency of bacterial protein synthesis associated with increasing passage rate (k p). We also hypothesized that decreasing pH would increase the need for isobutyrate over 2-methylbutyrate. To study these effects independent from other sources of variation in vivo, we evaluated continuous cultures without (control) versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate), low versus high k p of the particulate phase (2.5 vs. 5.0%/h), and high versus low pH (ranging from 6.3 to 6.8 diurnally vs. 5.7 to 6.2) in a 2 × 2 × 2 factorial arrangement of treatments. Diets were 50% forage pellets and 50% grain pellets administered twice daily. Without an interaction, NDF degradability tended to increase from 29.7 to 35.0% for main effects of control compared with BCVFA treatments. Provision of BCVFA increased methanogenesis, presumably resulting from improved NDF degradability. Decreasing pH decreased methane production. Total volatile fatty acid (VFA) and acetate production were decreased with increasing k p , even though true organic matter degradability and bacterial nitrogen flow were not affected by treatments. Decreasing pH decreased acetate but increased propionate and valerate production, probably resulting from a shift in bacterial taxa and associated VFA stoichiometry. Decreasing pH decreased isobutyrate and isovalerate production while increasing 2-methylbutyrate production on a net basis (subtracting doses). Supplementing BCVFA improved NDF degradability in continuous cultures administered moderate (15.4%) crude protein diets (excluding urea in buffer) without major interactions with culture pH and k p. [ABSTRACT FROM AUTHOR]

ABSTRACT: The co-digestion of swine manure with vegetable waste is an alternative that can increase the production of biogas and methane generated by the isolated digestion of manure. However, recommendations that are based on the best ratio between manure and forage, as well as the age of harvest, are still scarce in the literature. This study was conducted to evaluate inclusions (0, 25, 50, 75 and 100%) of the total solids (TS) of Elephant grass (Pennisetum purpureum Schum) harvested at two ages medium age (MA) at 45 days of growth and advanced age (AA) at 90 days in co-digestion with swine manure, using an entirely randomized design in a 5x2 factorial scheme. Batch digesters were used and biogas production was monitored for 12 weeks. There was influence of forage age (P

Three experiments assessed branched-chain volatile fatty acid (BCVFA) stimulation of neutral detergent fiber (NDF) disappearance after 24 h of incubation in batch cultures derived from ruminal fluid inocula that were enriched with particulate-phase bacteria. In experiment 1, a control was compared with 3 treatments with isomolar doses of all 3 BCVFA (plus valerate), all 3 branched-chain AA (BCAA), or half of each BCVFA and BCAA mix with either alfalfa or grass hays (50%) and ground corn grain (50%). A portion of the BCAA and BCVFA doses were enriched with 13C, and valerate (also enriched with 13C) was added with BCVFA. Although BCAA yielded a similar production of BCVFA compared with dosing BCVFA, equimolar substitution of BCVFA for BCAA decreased the percentage of N in bacterial pellets when alfalfa hay was fed but increased N when grass hay was fed. Substituting BCVFA for BCAA increased total fatty acid (FA) concentration with alfalfa hay. Dosing of BCAA or BCVFA did not affect total branched-chain FA, iso -FA, or anteiso -FA percentages in bacterial total FA, whereas numerous individual FA isomers and their 13C enrichments were affected by these treatments. Increasing recovery of the 13C dose from respective labeled BCVFA primers indicated facilitated BCVFA uptake and incorporation into FA compared with BCAA, whereas increased recovery of 13C from labeled BCAA in the bacteria pellet but not in the FA fraction suggested direct assimilation into bacterial protein. The BCVFA and valerate were dosed in varying combinations that either summed to 4 m M (experiment 2) or had only 1 m M no matter what combination (experiment 3). In general, grass hay was more responsive to stimulation in NDF digestibility by BCVFA than was alfalfa hay, which was attributed to the higher degradable protein in the latter. The net production of the BCVFA (after subtracting dose) was affected by source and combination of BCVFA. Isovalerate dosing tended to increase its own net production; in contrast, isobutyrate seemed to be used more when it was added alone, but 2-methylbutyrate seemed to be preferred over isobutyrate when 2-methylbutyrate was added. Results supported potential interactions, including potential feedback in production from feed BCAA or increased concentration-dependent competition for dosed BCVFA into cellular products. Under our conditions, the BCVFA appear to be more readily available than BCAA, probably because of regulated BCAA transport and metabolism. Valerate consistently provided no benefit. Using nonparametric ranking, all 3 BCVFA or either isovalerate or isobutyrate (both yielding iso -FA) should be combined with 2-methylbutyrate (yielding anteiso -FA) as a potential opportunity to improve NDF digestibility when rumen-degraded BCAA are limited in diets to decrease environmental impact from N in waste. [ABSTRACT FROM AUTHOR]

• A novel time-dependent micromechanics model is proposed for dissolvable composites. • The performance of composite is linked to dissolution and diffusion rates. • A comprehensive parametric study revealing the impact of key factors is presented. • The model is successfully applied to literature data on single polymer composites. This paper proposes a novel micromechanics model tailored for dissolvable composites, where the inclusion undergoes dissolution and diffusion within the matrix, with the aim of analytically predicting the time-dependent properties of composites. The dissolution of inclusion leads to a reduction of its volume fraction and the formation of a growing interphase layer around the inclusion. This versatile model is applicable to both short-term dissolutions, as observed in the fabrication process of composites and long-term degradation occurring in high-temperature or corrosive environments, common in industrial and biological applications. Dimensionless expressions for time-dependent volume fractions of composite components are related to the dissolution and the diffusion rates, and a micromechanics three-phase model is established to evaluate the properties of the composite as a function of dissolution time. A detailed parametric study is performed to demonstrate the effect of all the parameters on the final properties. The model is successfully applied to the experimental data in the literature to show its capability and flexibility in predicting the practical dissolution examinations. The introduced model provides a pioneering framework for the future evolution of the dissolvable micromechanics concept. [Display omitted] [ABSTRACT FROM AUTHOR]

Bio-fermentation technology has been successfully developed for ensiling rice straw; however, its effects on the particle-attached microbial community remains unknown. Therefore, rice straw (RS) and bio-fermented rice straw (BFRS) were used as substrates for in vitro rumen fermentation to investigate the effect of bio-fermentation on particle-attached microbial community, as well as their effects on gas and methane production, fermentation products, and fiber degradation. Our results have shown that total gas production, fiber degradation, and in vitro fermentation products were significantly higher (p < 0.05) for the BFRS than the RS, while methane concentration in total gas volume was significantly lower (p < 0.05) for the BFRS than RS. Linear discriminant effect size (LefSe) analysis revealed that the relative abundance of the phyla Bacteroidetes, Fibrobacteres, Proteobacteria, and Lantisphaerae, as well as the genera Fibrobacter, Saccharofermentans, and [Eubacterium] ruminantium groups in the tightly attached bacterial community, was significantly higher (p < 0.05) for the BFRS than the RS, whereas other microbial communities did not change. Thus, bio-fermentation altered the tightly attached bacterial community, thereby improving gas production, fiber degradation, and fermentation products. Furthermore, bio-fermentation reduced methane concentration in total gas volume without affecting the archaeal community.

Coffee hulls obtained from dry processing, have the potential to be used in ruminant diets. Objective: To evaluate the chemical composition and in situ degradability of dry matter (DM) and neutral detergent fiber (NDF) of coffee hulls treated with calcium oxide (CaO) in different environmental conditions (EC). Methods: Coffee hulls were subjected to treatments distributed in a 2 × 2 factorial arrangement, consisting of two levels of CaO (0 and 5%, on a DM basis) and two environmental conditions (aerobiosis and anaerobiosis) in a completely randomized design with four replicates, totaling sixteen experimental units. Five-gram samples were incubated in the rumen of two male cattle for 0, 3, 6, 9, 12, 24, 48, 72, 96, and 120 h. Results: Regarding dry matter degradation kinetic parameters, except for fraction b, the potential and effective degradability was affected (p<0.05) by a CaO × EC interaction. As for estimated fiber degradation parameters, the potentially degradable fraction b was affected (p<0.05) by CaO and EC. Treatment with CaO increased fraction b in 4.08 percentage points. Conclusions: The use of CaO in the treatment of coffee hulls increases the effective and potential degradability of DM and reduces the undegradable fiber fraction. Anaerobic condition is the best environment for the treatment of coffee hulls with CaO. [ABSTRACT FROM AUTHOR]

Introduction: This study examines the optimum conversion of Wuzhishan pig manure by Black Soldier Fly Larvae (BSFL) at various phases of development, as well as the impact of gut microbiota on conversion efficiency., Method and Results: In terms of conversion efficiency, BSFL outperformed the growing pig stage (GP) group, with significantly higher survival rates (96.75%), fresh weight (0.23 g), and larval conversion rate (19.96%) compared to the other groups. Notably, the GP group showed significant dry matter reductions (43.27%) and improved feed conversion rates (2.17). Nutritional composition varied, with the GP group having a lower organic carbon content. High throughput 16S rRNA sequencing revealed unique profiles, with the GP group exhibiting an excess of Lactobacillus and Clostridium . Promising cellulose-degrading bacteria in pig manure and BSFL intestines, including Bacillus cereus and Bacillus subtilis , showed superior cellulose degradation capabilities. The synergy of these thermophilic bacteria with BSFL greatly increased conversion efficiency. The BSFL1-10 group demonstrated high growth and conversion efficiency under specific conditions, with remarkable larval moisture content (71.11%), residual moisture content (63.20%), and waste reduction rate (42.28%)., Discussion: This study sheds light on the optimal stages for BSFL conversion of pig manure, gut microbiota dynamics, promising thermophilic cellulose-degrading bacteria, and the significant enhancement of efficiency through synergistic interactions. These findings hold great potential for sustainable waste management and efficient biomass conversion, contributing to environmental preservation and resource recovery., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shao, Zhao, Rehman, Cai, Zheng, Huang and Zhang.)

In horses, abrupt changes from high-fiber (HF) to high-starch (HS) diets can affect the cecal and colonic microbiota. This study investigated modifications and recovery of fecal microbiota after two consecutive abrupt dietary changes. Twelve horses fed HF for 2 weeks were changed to HS for 5 days then returned to HF for 7 weeks. Six received lactic acid bacteria supplementation. Bacterial population diversity, structure, and activity, especially fibrolysis, were assessed to obtain an overview of alteration in hindgut microbiota. Two days after the abrupt change from HF to HS, the findings in feces were consistent with those previously reported in the cecum and colon, with a decrease in fibrolytic activity and an increase in amylolytic activity. Fecal parameters stabilized at their basal level 3–4 weeks after the return to HF. A bloom of cellulolytic bacteria and lower pH were observed after 1.5 weeks, suggesting a higher level of fiber degradation. In supplemented horses the relative abundance of potentially fibrolytic genera was enhanced 2 days after HS and 2 days to 2–3 weeks after the return to HF. Fecal analysis could be a promising technique for monitoring hindgut microbial variations accompanying dietary changes.

Information on the effects of different yeast species on ruminal fermentation is limited. This experiment was conducted in a 3×4 factorial arrangement to explore and compare the effects of addition of three different live yeast species (Candida utilis 1314, Saccharomyces cerevisiae 1355, and Candida tropicalis 1254) at four doses (0, 0.25×107, 0.50×107, and 0.75×107 colony-forming unit [cfu]) on in vitro gas production kinetics, fiber degradation, methane production and ruminal fermentation characteristics of maize stover, and rice straw by mixed rumen microorganisms in dairy cows. The maximum gas production (Vf), dry matter disappearance (IVDMD), neutral detergent fiber disappearance (IVNDFD), and methane production in C. utilis group were less (p

The aim of this study was to improve the utilization of rice straw as forage in ruminants by investigating the degradation pattern of rice straw in the dairy cow rumen. Ground up rice straw was incubated in situ in the rumens of three Holstein cows over a period of 72 h. The rumen fluid at 0 h and the rice straw at 0.5, 1, 2, 4, 6, 12, 24, 48, and 72 h were collected for analysis of the bacterial community and the degradation of the rice straw. The bacterial community and the carbohydrate-active enzymes in the rumen fluid were analyzed by metagenomics. The diversity of bacteria loosely and tightly attached to the rice straw was investigated by scanning electron microscopy and Miseq sequencing of 16S rRNA genes. The predominant genus in the rumen fluid was Prevotella, followed by Bacteroides, Butyrivibrio, unclassified Desulfobulbaceae, Desulfovibrio, and unclassified Sphingobacteriaceae. The main enzymes were members of the glycosyl hydrolase family, divided into four categories (cellulases, hemicellulases, debranching enzymes, and oligosaccharide-degrading enzymes), with oligosaccharide-degrading enzymes being the most abundant. No significant degradation of rice straw was observed between 0.5 and 6 h, whereas the rice straw was rapidly degraded between 6 and 24 h. The degradation then gradually slowed between 24 and 72 h. A high proportion of unclassified bacteria were attached to the rice straw and that Prevotella, Ruminococcus, and Butyrivibrio were the predominant classified genera in the loosely and tightly attached fractions. The composition of the loosely attached bacterial community remained consistent throughout the incubation, whereas a significant shift in composition was observed in the tightly attached bacterial community after 6 h of incubation. This shift resulted in a significant reduction in numbers of Bacteroidetes and a significant increase in numbers of Firmicutes. In conclusion, the degradation pattern of rice straw in the dairy cow rumen indicates a strong contribution by tightly attached bacteria, especially after 6 h incubation, but most of these bacteria were not taxonomically characterized. Thus, these bacteria should be further identified and subjected to functional analysis to improve the utilization of crop residues in ruminants.

This study aimed to evaluate the effects of including virginiamycin (VM) in two levels, the proteinenergy supplement for growing beef cattle diet with the tropical grass base in the dry season. Three treatments were evaluated: control treatment, only Mineral Supplement ME - Production - F.10 proteinenergy (SPE); 100 virginiamycin treatment (VM 100) + SPE 108 mg (Phigrow®) VM / animal / day and treatment virginiamycin 200 (200 MV) + SPE 216 mg (Phigrow®) VM / animal / day. The variables analyzed were the supplement intake (SI), average daily gain (ADG), biometric measurements and body condition score (BCS) in experiment 1 and the average daily supplement intake (ADSI), ruminal pH, ammonia nitrogen, in situ ruminal degradability of dry matter (DM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) in experiment 2. There was no statistical difference for ADG, SI and biometric measurements (P>0.05), ADG for VM 200 of 0,431; VM 100 of 0.391 and control 0.398 kg/animal/day. There was no significant difference (P>0.05) for ruminal pH, the ammonia concentration and the variables at the in situ degradability of DM, NDF and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF and ADF.

Novel polymeric flame retardants based on two acrylamides and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) or 5,5-dimethyl-[1,3,2]dioxaphosphinane-2-oxide (DDPO) are described for several applications in HexFlow® RTM6, a high-performance epoxy resin. Neat resin samples and carbon fiber-reinforced composites were tested for their glass transition temperatures (dynamic mechanical analysis), thermal stability (thermogravimetric analyses), flammability (UL94) and flame-retardant performance (Cone Calorimetry). Additionally, the fiber degradation occurring during combustion of carbon fiber-reinforced epoxy resins was observed by scanning electron microscopy to show the fiber protecting effect of these flame retardants. Whereas DOPO-containing polyacrylamides acting mainly in the gas phase showed the best flame retardant efficiency, DDPO-containing polyacrylamides acting mainly in the condensed phase showed the best fiber protection. A mixed polyacrylamide was synthesized to combine these effects. This thermoplastic is soluble in the resin and, therefore, suitable for injection molding processes. Interlaminar shear strength measurements showed no negative effect of the flame retardant. The versatility of these flame retardants is shown by investigations dealing with boehmite as synergist in neat resin samples.

Ruminants have a unique ability to derive energy from the degradation of plant polysaccharides through the activity of the rumen microbiota. Although this process is well studied in vitro, knowledge gaps remain regarding the relative contribution of the microbiota members and enzymes in vivo. The present study used RNA-sequencing to reveal both the expression of genes encoding carbohydrate-active enzymes (CAZymes) by the rumen microbiota of a lactating dairy cow and the microorganisms forming the fiber-degrading community. Functional analysis identified 12,237 CAZymes, accounting for 1% of the transcripts. The CAZyme profile was dominated by families GH94 (cellobiose-phosphorylase), GH13 (amylase), GH43 and GH10 (hemicellulases), GH9 and GH48 (cellulases), PL11 (pectinase) as well as GH2 and GH3 (oligosaccharidases). Our data support the pivotal role of the most characterized fibrolytic bacteria (Prevotella, Ruminocccus and Fibrobacter), and highlight a substantial, although most probably underestimated, contribution of fungi and ciliate protozoa to polysaccharide degradation. Particularly these results may motivate further exploration of the role and the functions of protozoa in the rumen. Moreover, an important part of the fibrolytic bacterial community remains to be characterized since one third of the CAZyme transcripts originated from distantly related strains. These findings are used to highlight limitations of current metatranscriptomics approaches to understand the functional rumen microbial community and opportunities to circumvent them. [ABSTRACT FROM AUTHOR]

Feeding animals with pelleted total mixed ration (TMR) is a widespread practice as it reduces feed losses during storage, feeding and the animal's sorting. Supplementation of yeast culture can promote rumen fiber degradation, which may occur through stabilizing rumen pH. There are few studies, however, evaluating the optimal supplementation level of yeast culture in pelleted TMR in which rumen pH has been continuously measured. This study aimed to determine the optimal level of a commercial yeast culture product (of which the number of viable CFU was not measured) mixed and pelleted with the TMR, on fiber degradation in situ , rumen pH dynamics, rumen fermentation variables, and the bacterial community composition of rumen fluid. Under a partial Latin square design, a total of twelve wethers equipped with permanent rumen fistulas were randomly assigned to four treatments of yeast culture at 0, 0.5, 1.0, or 2.0% dietary dry matter. After a 28 d period comprising 21 d for adaptation and 7 d for measurements, each group of three wethers was randomly reassigned to another treatment. Thus, each yeast supplementation level was fed to a total of six animals. In situ dry matter (DMD) and neutral detergent fiber (NDFD) disappearance of corn stover, mean rumen pH, total volatile fatty acids concentration, acetate, propionate, and n -butyrate molar percentages, and the acetate to propionate ratio were influenced (P ≤ 0.05) by dietary treatments. Quadratic (P ≤ 0.03) responses to increasing yeast culture supplementation level were observed for mean rumen pH, daily duration of pH below a 5.8 threshold considered inhibitory for fibrolysis, and the molar percentages of propionate, n- butyrate, and the acetate to propionate ratio. The highest in situ DMD and NDFD occurred when yeast was supplemented at 1%. Increasing yeast culture supplementation level tended to quadratically increase the abundance of fibrolytic bacterial genera NK4A214 and FD2005, which peaked at 1% yeast culture in the diet DM. The molar percentage of n -butyrate was positively correlated with the relative abundance of Rikenellaceae _RC9 and NK4A214. In our study, supplementation of pelleted TMR with 1% yeast culture provided as residual yeast medium components, was optimal for fiber degradation of forage fed to ruminants. Members of genera NK4A214 and FD2005 may contribute extra n -butyrate. • The highest in situ DM and NDFD occurred when yeast was supplemented at 1%. • Members of genera NK4A214 and FD2005 may contribute extra n -butyrate. • Yeast culture supplementation ameliorated rumen pH drops. • 1% yeast culture was optimal for fiber degradation of forage fed to ruminants. [ABSTRACT FROM AUTHOR]

Fibrobacter succinogenes is a cellulolytic bacterium that plays an essential role in the degradation of plant fibers in the rumen ecosystem. It converts cellulose polymers into intracellular glycogen and the fermentation metabolites succinate, acetate, and formate. We developed dynamic models of F. succinogenes S85 metabolism on glucose, cellobiose, and cellulose on the basis of a network reconstruction done with the automatic reconstruction of metabolic model workspace. The reconstruction was based on genome annotation, five template-based orthology methods, gap filling, and manual curation. The metabolic network of F. succinogenes S85 comprises 1,565 reactions with 77% linked to 1,317 genes, 1,586 unique metabolites, and 931 pathways. The network was reduced using the NetRed algorithm and analyzed for the computation of elementary flux modes. A yield analysis was further performed to select a minimal set of macroscopic reactions for each substrate. The accuracy of the models was acceptable in simulating F. succinogenes carbohydrate metabolism with an average coefficient of variation of the root mean squared error of 19%. The resulting models are useful resources for investigating the metabolic capabilities of F. succinogenes S85, including the dynamics of metabolite production. Such an approach is a key step toward the integration of omics microbial information into predictive models of rumen metabolism. IMPORTANCE F. succinogenes S85 is a cellulose-degrading and succinate-producing bacterium. Such functions are central for the rumen ecosystem and are of special interest for several industrial applications. This work illustrates how information of the genome of F. succinogenes can be translated to develop predictive dynamic models of rumen fermentation processes. We expect this approach can be applied to other rumen microbes for producing a model of rumen microbiome that can be used for studying microbial manipulation strategies aimed at enhancing feed utilization and mitigating enteric emissions., Competing Interests: The authors declare no conflict of interest.

In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in 2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids, plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice. [ABSTRACT FROM AUTHOR]

Long fiber reinforced thermoplastics (LFT) were processed by in-line compounding equipment with a modified single screw extruder. A pulse stimulus response technique using PET spheres as the tracer was adopted to obtain residence time distribution (RTD) of extrusion compounding. RTD curves were fitted by the model based on the supposition that extrusion compounding was the combination of plug flow and mixed flow. Characteristic parameters of RTD model including P the fraction of plug flow reactor (PFR) and d the fraction of dead volume of continuous stirred tank reactor (CSTR) were used to associate with fiber degradation presented by fiber length and dispersion. The effects of screw speed, mixing length and channel depth on RTD curves, and characteristic parameters of RTD models as well as their effects on the fiber degradation were investigated. The influence of shear force with different screw speeds and variable channel depth on fiber degradation was studied and the main impetus of fiber degradation was also presented. The optimal process for obtaining the balance of fiber length and dispersion was presented.

Information on the effects of different yeast species on ruminal fermentation is limited. This experiment was conducted in a 3×4 factorial arrangement to explore and compare the effects of addition of three different live yeast species (Candida utilis 1314, Saccharomyces cerevisiae 1355, and Candida tropicalis 1254) at four doses (0, 0.25×107, 0.50×107, and 0.75×107 colony-forming unit [cfu]) on in vitro gas production kinetics, fiber degradation, methane production and ruminal fermentation characteristics of maize stover, and rice straw by mixed rumen microorganisms in dairy cows. The maximum gas production (Vf), dry matter disappearance (IVDMD), neutral detergent fiber disappearance (IVNDFD), and methane production in C. utilis group were less (p<0.01) than other two live yeast supplemented groups. The inclusion of S. cerevisiae reduced (p<0.01) the concentrations of ammonia nitrogen (NH3-N), isobutyrate, and isovalerate compared to the other two yeast groups. C. tropicalis addition generally enhanced (p<0.05) IVDMD and IVNDFD. The NH3-N concentration and CH4 production were increased (p<0.05) by the addition of S. cerevisiae and C. tropicalis compared with the control. Supplementation of three yeast species decreased (p<0.05) or numerically decreased the ratio of acetate to propionate. The current results indicate that C. tropicalis is more preferred as yeast culture supplements, and its optimal dose should be 0.25×107 cfu/500 mg substrates in vitro. [ABSTRACT FROM AUTHOR]

Measures of the quantity of chemical components are used to make certain assumptions about forage or feed quality. However, additional ruminal degradation kinetic measures are necessary for modern nutrient requirement models and more accurate estimates of intake and digestibility. The extent and rate of ruminal degradation is most easily and inexpensively measured with in vitro and in situ experimental techniques. This presentation is a summary of updates to these techniques in the last thirty years. The Daisy Incubator by ANKOM Technology has been marketed for over twenty-five years. This product resulted in standardization of materials and methods used to measure in vitro true digestibility. The biological component of the technique, ruminal fluid, is still a variable component since it is influenced by fistulated animal diet and collection and transport procedures. Despite several calls through review papers over the last thirty years, the in situ experimental technique is not standardized and there remains variation among laboratories and experiments. Animal species, ingredients and quantity of animal diet, grind size of the test material, bag pore size, ratio of the sample: surface area of bag, replications, sample treatment prior to incubation and after removal, incubation method, microbial contamination, bag washing, and even laboratory balance weigh method contribute to the variation among in situ experiments. Once in situ data is obtained, it is typically fitted to a first order exponential model and parameters estimated without determining if the model is the best fit. Perhaps understanding the reasons that standardization of in situ methodology have failed would facilitate ways to make standardization possible. In the meantime, careful in situ experimental technique results in measures that are valuable inputs into models for nutrient requirements, intake, and digestibility and an increase in knowledge about ruminal degradation kinetics, despite the inability to compare results across laboratories or experiments. [ABSTRACT FROM AUTHOR]

Feeding with a suitable level of milk replacer (MR) can improve the survival rate and stimulate the growth potential of early lambs. However, feeding excessive MR might be detrimental to rumen development and microbial colonization. Herein, we investigated the effects of feeding different levels of MR on rumen digestive function and ruminal microorganisms. Fourteen healthy male Hu lambs with similar birth weights and detailed pedigree records were divided into two groups to receive low (2% of average body weight per day) and high (4% of average body weight per day) levels of MR. We analyzed the effects of the MR feeding level on growth performance, fiber degradation rates, rumen fermentation parameters, enzyme activities and rumen histomorphology. We found that feeding with a high level of MR improved the average daily gain of early lambs, but decreased the starter intake, rumen weight and papillae length. We also analyzed the effects of the MR feeding level on the rumen microbiota using 16S-rRNA amplicon sequencing data. The results showed that high a MR feeding level increased the rumen microbial diversity but decreased the abundance of many carbohydrate degrading bacteria. Several bacterial genera with significant differences correlated positively with rumen cellulase activity and the acid detergent fiber degradation rate. Our results suggested that a high level of MR could improve the growth performance of early lambs in the short term; however, in the long term, it would be detrimental to rumen development and have adverse effects on the adaptation process of the microbiota to solid feed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Huang, Wang, Zhang, Chen, Li, Wang, Zhang, Wang, Zhang, Cui and Ma.)