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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]

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]

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]

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]

Simple Summary: The equine hindgut is colonized by microorganisms, some of which are involved in fiber digestion and are crucial for the horse's nutrition and health. These key microorganisms are very sensitive to dietary changes, which have been identified as a risk factor for colics. This study assessed the stressful effect of two consecutive abrupt dietary changes on the diversity, the composition, and the activity of fecal microorganisms focusing on fibrolytic bacteria. Twelve horses were subjected to an abrupt change from forage to a concentrate-rich diet, followed by a second change from a concentrate to forage-rich diet 5 days later. Half of the horses were given a supplement of living bacteria as a probiotic. Two days after the sudden change from forage to concentrate diet, the proportions and types of microorganisms were altered drastically, as was their capacity to degrade fibers. After this dietary stress, it took 3–4 weeks of a high-fiber diet to recover the basal state. Supplementation with probiotics promoted an earlier recovery of fibrolytic bacteria after the dietary stress. Abrupt dietary changes should be limited in horse management to protect the hindgut microorganisms and their capacity to use forage fibers, and consequently to limit the development of colic. 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. [ABSTRACT FROM AUTHOR]

Based on fifteen European plant species, a statistical model for the estimation of the anaerobic biodegradability of plant material was developed. We show that this new approach represents an accurate and cost-effective method to identify valuable energy plants for sustainable energy production. In particular, anaerobic biodegradability (Bo) of lignocellulosic material was empirically found to be related to the amount of cellulose plus lignin, as analytically assessed by the van Soest method, i.e., the acid detergent fiber (ADF) value. Apart from being theoretically meaningful, the ADF-based empirical model requires the least effort compared to the other four proposed conceptual models proposed, as individual fractions of cellulose, hemicellulose, and lignin do not need to be assessed, which also enhances the predictive accuracy of the model's estimation. The model's results showed great predictability power, allowing us to identify interesting crops for sustainable crop rotations. Finally, the model was used to predict Bo of 114 European plant samples that had been previously characterized by means of the van Soest method. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]