Phleum Pratense Research Articles

Insulin dysregulated horses metabolic responses to forage pellets

Hyperinsulinemia-associated laminitis (HAL) is the primary concern for insulin dysregulated (ID) equids and their insulin response to the consumption of oral, nonstructural carbohydrates (NSC) has been shown to be a risk predictor for HAL development. This randomized, crossover study's objective was to examine the insulinemic responses to 3 forage pellets (1 g/kg BW) (timothy hay, TH, 9.5 % CP & 10 % NSC DM; alfalfa hay, AH, 16.3 % CP & 9.8 % NSC DM; timothy-alfalfa hay; TAH, 17.2 % CP & 9.8 % NSC DM) along with a positive (dehulled oats; OG, 14.7 % CP & 59.7 % NSC DM) and negative dietary challenge control (low-NSC; LNSC, 12.8 % CP & 5.4 % NSC DM) of ID (n = 8; 16.1 ± 2.2 yr; 565.4 ± 99.1 kgs.) and non-ID (NID; n = 7; 17.0 ± 2.8 yr; 583.6 ± 57.9 kgs.) horses. ID horses had higher positive incremental area under the curve for insulin (IAUCi) (ID: 890 ± 925 µIU/mL*minute vs. NID: 225 ± 228 µIU/mL*minute), peak (ID: 101.5 ± 80.72 µIU/mL vs. NID: 25.7 ± 7.2 µIU/mL), and delta (ID: 45.5 ± 77.1 µIU/mL vs. NID: 4.9 ± 5.3 µIU/mL) insulin for all forage pellets compared to NID (p < 0.01). ID horses IAUCi for the forage pellets was not different compared to the LNSC (218 ± 327 µIU/mL*minute) but was different from OG (10,522 ± 4,565 µIU/mL*minute). ID horses’ lack of an augmented insulinemic response to the low NSC forage pellets (fed in small amounts) indicates that they could be a safe feedstuff for ID animals.

Тимофеевка луговая (Phleum pratense L.): биологические особенности, хозяйственное значение, особенности сорта ВИК 911, технологические приемы семеноводства

Meadow timothy grass (Phleum pratense L.) is an excellent traditional crop for creating hayfields and pasture of long-term use. This is a long-term riding grain, characterized by such irreplaceable qualities as durability, high yield of hay and green mass, high leafiness, good feed quality indicators, make it indispensable when creating hayfields and other types of forage lands not only in Russia, but also abroad. Timothy grass is one of the main components of grass mixtures for haymaking, especially with the participation of meadow clover, alfalfa, and it is also an excellent phytomeliorative culture that restores soil fertility. The most important issues of seed production of meadow timothy grass are such technological techniques as doses and timing of nitrogen fertilizers, seeding rates and methods of sowing seeds, as well as harvesting in accordance with the biological characteristics of the new variety of timothy grass VIK 911. As our research has shown, meadow timothy grass of the new variety VIK 911 should be sown in an ordinary way, with a seeding rate of 5–7 kg/ha, while nitrogen fertilizers should be applied better in spring at a dose of 45–60 kg/ha, or in two terms: in early autumn, in early September, at a dose of 30–45 kg/ha and in spring at a dose of 45 kg/ha. Meadow timothy grass has a good range of possible seed harvesting (6–8 days) due to the resistance to seed shedding.

Evaluating the effects of wilting, mixing with timothy and silage additive application on red clover silage quality

Red clover is typically produced as a mixed stand with grasses, which may lead to suboptimal fertilization and harvest time practices, resulting in poor survival of red clover. Further, unknown proportions of red clover in mixed swards complicate ration formulation for livestock. Thus, producing red clover as pure stands could offer benefits, but it may be difficult to ensile. The objective of the current study was to evaluate major management possibilities such as wilting, inclusion of timothy grass and different types of additives in optimizing the ensilage of red clover. Low DM silages were poorly preserved with high pH, elevated acetic acid concentrations and proportions of ammonia-N in total N, as well as depleted water-soluble carbohydrate levels. Moderate wilting clearly improved the fermentation quality of silages. Further, the use of formic acid-based additives improved the fermentation quality of the silages, the effect being more pronounced in the low than medium dry matter silages. The composition of red clover and timothy were rather similar regarding dry matter content and ensilability. This was probably the reason why clear benefits in silage quality from timothy inclusion could not be demonstrated.

Effects of Drought Stress on Red Clover-Grass Mixed Stands Compared to Grass Monoculture Stands in Nitrogen-Deficient Systems

Drought stress is one of the major abiotic stress factors affecting forage production; thus, it is essential to obtain a better understanding of how forage responds to drought. The main objective of this study was to evaluate how legume-grass mixed forage stands respond to drought stress when compared to grass monoculture. A greenhouse pot experiment was conducted using a red clover (Trifolium pratense L.)—timothy grass (Phleum pratense L.) mixed stand and a timothy monoculture stand, where plants were subjected to severe drought (20% field capacity—FC), moderate drought (40% FC), and well-watered (80% FC) conditions for four weeks and subsequently allowed to recover for another four weeks by adjusting moisture back to 80% FC. Both moderate and severe droughts significantly reduced the shoot biomass of the mixed stand, while no difference was exhibited in the timothy monoculture. The shoot biomass and nitrogen fixation capacity of red clover were reduced under drought stress. However, red clover plants subjected to moderate drought were able to recover shoot growth and nitrogen fixation capacity during the recovery phase, allowing more biologically fixed nitrogen and shoot nitrogen production similar to the plants growing under well-watered conditions. Overall, the results demonstrate that the inclusion of legumes in forage mixtures enhances resilience to moderate drought stress.

Economic and energy efficiency of perennial agrophytocenoses with the jerusalem artichoke participation in the Karelia conditions

The article presents the results of the research of cultivation technology of topinambur with perennial legumes and grasses in the Republic of Karelia. The highest dry mass yield (9.3 t/ha) has been achieved by joint agrophytocenosis with Helianthustuberosus L. in comparison with the control of timothy grass + brome grass + clover (7.9 t/ha). Inclusion of topinambur has increased productivity of perennial stands of grass (7.99 thousand fodder units, 97.0 GJ of metabolizable energy, 1.34 t of crude protein per 1 ha). On the basis of economic and energy efficiency, it has been proved that agrophytocenoses of topinambur and perennial legumes and grasses are the most economically efficient. The maximum value of the agro-energy coefficient in terms of metabolizable energy has been obtained in the following variant: timothy grass + brome grass + clover + topinambur.

Biotesting of Binding Reagents for Dust Suppression on Rare Metal Tailings Waste in the Arctic Zone of the Russian Federation

The paper presents the results of environment safety assessment of Russian and foreign binding reagents (Syntex-65, Lukoil DD 3000, Voltes PP-300 and Dustbind) used for remediation of objects of accumulated environmental damage in the Murmansk region. The paper shows that in the presence of anti-erosion and water-retentive phytocenosis on technosoil of loparite ore tailings, these reagents have a partial inhibitory effect on the first first seedlings of timothy grass (Phleum pratense L.) and red fescue (Festuca rubra L.) and statistically (p &lt;0.005) affect its main quality indicators (plant height and biomass). Effective methods of applying reagents to the dusty surface of technosoil were identified. When using the Lukoil DD 3000 reagent as an analogue of Dustbin – continuous, for Voltes PP-300 – fragmentary, when using Syntex-65 – continuous in the mode of simulated hydroseeding.

Rumen fermentation of meal-fed sheep in response to diets formulated to vary in fiber and protein degradability.

The concentration of volatile fatty acid (VFA) provides an imprecise view of VFA dynamics due to the confounding effects of fluid pool size and dynamics. Determination of VFA flux using isotope is expensive and a complex methodology. Therefore, a rapid and affordable approach to explore VFA dynamics may allow comprehensive characterization of VFA availability. The objective of this study was to explore the use of VFA dynamics generated by meal feeding to derive time-series rates of VFA apparent appearance and disappearance driven by different protein and fiber sources. Six ruminally cannulated wethers were fed diets containing timothy hay or beet pulp (TH and BP) and soybean meal (SBM) or heated soybean meal (HSBM). Diets were, TH + HSBM; TH + SBM; BP + HSBM; and BP + SBM and the experimental design was a partially replicated 4 × 4 Latin Square. Concentrations of VFA and polyethylene glycol (PEG) in rumen fluid samples were estimated. Concentrations of PEG were used to estimate fluid passage and volume to calculate VFA mass, and fluid-mediated exit. Maximum apparent appearance rate (mmol/h), the rate of apparent appearance decline (mmol/mmol/h), mean apparent appearance flux (mmol/h), mean apparent disappearance (mmol/h), and apparent disappearance rate (mmol/mmol/h) were estimated by deriving a 1 pool model for each VFA on a mass basis where appearance was assumed to follow an exponential decay pattern and disappearance followed mass-action kinetics. Statistical analyses were conducted using a linear mixed effect regression with fixed effects for fiber source, protein source, and their interaction, as well as random effects for animal and period. Rumen fluid volume (L) was greater in HSBM diets (P = 0.033) and fluid passage (%/h) was greater in SBM diets (P = 0.048). Concentrations (higher acetate and butyrate, P = 0.002 and 0.004, respectively) and molar proportions (higher valerate, P = 0.035) of VFA were affected only by fiber source; however, protein source and fiber source interacted to significantly influence apparent appearance rates and absorption rates of many major VFA. On a flux basis, HSBM supported significantly elevated mean disappearance of propionate (P = 0.033). This data demonstrates that time-series evaluation of fermentation dynamics, including fluid dynamics and VFA concentrations can be used to estimate apparent appearance and disappearance of VFA. Although further work is needed to confirm the alignment of these estimates with measurements of VFA supplies to the animal, this modeling approach may provide a simpler way to better understand the kinetics of rumen.

Allergic sensitization does not influence advancement or survival in oral cancer

A history of allergies has been said to be associated with a lower risk of head and neck cancer compared to the general population. However, it is not known whether having an allergic sensitization influences the prognosis and advancement of cancer disease. Thus, the aim of the study was to investigate the relationship between allergic sensitization and oral cancer advancement and patient survival. Allergen-specific IgE antibodies were investigated by ImmunoCAP™ Rapid in consecutive 80 patients with oral cancer. ImmunoCAP Rapid system tests a mix of representative inhalant allergens such as birch, timothy grass, mugwort, house dust mite, cat, dog, cockroach, olive (pollen), wall pellitory and mold. Eighty patients met the inclusion criteria for the study. Fifteen patients (19%) had positive ImmunoCAP test. There was no statistically significant difference in primary tumour size (T-stage) between groups (60% in allergy vs 68% in non-allergy had T1–T2 stage and 40% vs 32% T3–T4, respectively, p = 0.570). 27% of patients with allergy had nodal metastases compared with 37% of patients without allergy (p = 0.557). Both groups had comparable short-term survival. In conclusion, allergic sensitization does not seem to influence either the advancement or the short-term survival of patients with oral squamous cell carcinoma.

Response to Waterlogging Stress in Wild and Domesticated Accessions of Timothy (Phleum pratense) and Its Relatives P. alpinum and P. nodosum

Timothy (Phleum pratense) is a cool-season perennial forage grass widely grown for silage and hay production in northern regions. Climate change scenarios predict an increase in extreme weather events with fluctuating periods of high rainfall, requiring new varieties adapted to waterlogging (WL). Wild accessions could serve as germplasm for breeding, and we evaluated the responses of 11 wild and 8 domesticated accessions of timothy, P. nodosum and P. alpinum from different locations in northern Europe. Young plants at tillering stage were exposed to WL for 21 days in a greenhouse, and responses in growth allocation and root anatomy were studied. All accessions produced adventitious roots and changed allocation of growth between shoot and root as a response to WL, but the magnitude of these responses varied among species and among accessions. P. pratense responded less in these traits in response to WL than the other two species. The ability to form aerenchyma in the root cortex in response to WL was found for all species and also varied among species and among accessions, with the highest induction in P. pratense. Interestingly, some accessions were able to maintain and even increase root growth, producing more leaves and tillers, while others showed a reduction in the root system. Shoot dry weight (SDW) was not significantly affected by WL, but some accessions showed different and significant responses in the rate of production of leaves and tillers. Overall correlations between SDW and aerenchyma and between SDW and adventitious root formation were found. This study identified two wild timothy accessions and one wild P. nodosum accession based on shoot and root system growth, aerenchyma formation and having a root anatomy considered to be favorable for WL tolerance. These accessions are interesting genetic resources and candidates for development of climate-resilient timothy varieties.

Cereals-goat's rue agrocenoses in the conditions of the Upper Volga region

During 2015–2021 at the Gubino agro-polygon VNIIMZ, studies were carried out on hay-grass-goat-rue grass stands depending on the composition of the grass mixture and soil difference in the conditions of the Upper Volga region. Varieties of oriental goat's rue (Galega orientalis Lam.) - Gale, Yubilyar, Krivich and seeded cereal grasses - meadow timothy grass (Phleum pratense L.) Vic 9, awnless rump (Bromus inermis L.) Vegur, reed dwarf grass (Phalaris arundinacea L.) Ural. Sowing methods of grass stands are single-species and mixed - legumes, legumes-cereals and cereals. The research methodology included phenological observations, determining the density and height of herbage, studying the structure of the crop, the dynamics of the accumulation of dry and green mass, and processing statistical data. It has been established that, on average, over a seven-year observation period, the yield of legume-grass grass stands varied within 5.1-7.9 t/ha of dry weight. The maximum productivity was noted in 2017 - up to 11.7 t/ha of dried mass. The stem density of the sown legume component - oriental goat's rue, depending on the grass mixture and the year of the study, varied from 17 to 149 pcs/m2. The height of goat's rue plants on average for long-term observations with two-cutting use was 63-93 cm, for grass seeded grasses - 78-108 cm. Goat's rue had good foliage, the average share of leaves in the structure of the Eastern goat's rue crop for all years of research varied from 50.6 to 58.2%. The stem content was 41.4-48.9%. In single-species crops, the leaf content of eastern goat's rue reached 43.6-66.8% on average for 2 cuttings, and in a mixture with cereal grasses - 42.6-69.0%. The most productive were legume-cereal agrocenoses on gleyic soil.

Adoptive transfer of allergen-expressing B cells prevents IgE-mediated allergy.

Prophylactic strategies to prevent the development of allergies by establishing tolerance remain an unmet medical need. We previously reported that the transfer of autologous hematopoietic stem cells (HSC) expressing the major timothy grass pollen allergen, Phl p 5, on their cell surface induced allergen-specific tolerance in mice. In this study, we investigated the ability of allergen-expressing immune cells (dendritic cells, CD4+ T cells, CD8+ T cells, and CD19+ B cells) to induce allergen-specific tolerance in naive mice and identified CD19+ B cells as promising candidates for allergen-specific cell therapy. For this purpose, CD19+ B cells were isolated from Phl p 5-transgenic BALB/c mice and transferred to naive BALB/c mice, pre-treated with a short course of rapamycin and an anti-CD40L antibody. Subsequently, the mice were subcutaneously sensitized three times at 4-week intervals to Phl p 5 and Bet v 1 as an unrelated control allergen. Allergen-expressing cells were followed in the blood to monitor molecular chimerism, and sera were analyzed for Phl p 5- and Bet v 1-specific IgE and IgG1 levels by RBL assay and ELISA, respectively. In vivo allergen-induced lung inflammation was measured by whole-body plethysmography, and mast cell degranulation was determined by skin testing. The transfer of purified Phl p 5-expressing CD19+ B cells to naive BALB/c mice induced B cell chimerism for up to three months and prevented the development of Phl p 5-specific IgE and IgG1 antibody responses for a follow-up period of 26 weeks. Since Bet v 1 but not Phl p 5-specific antibodies were detected, the induction of tolerance was specific for Phl p 5. Whole-body plethysmography revealed preserved lung function in CD19+ B cell-treated mice in contrast to sensitized mice, and there was no Phl p 5-induced mast cell degranulation in treated mice. Thus, we demonstrated that the transfer of Phl p 5-expressing CD19+ B cells induces allergen-specific tolerance in a mouse model of grass pollen allergy. This approach could be further translated into a prophylactic regimen for the prevention of IgE-mediated allergy in humans.

Anaphylaxis in Clinical Trials of Sublingual Immunotherapy Tablets

There is no consensus method to identify anaphylaxis in sublingual immunotherapy (SLIT) trials. Standardized Medical Dictionary for Regulatory Activities (MedDRA) queries (SMQs) are standardized groupings of MedDRA terms used in drug safety monitoring. To develop a method to identify potential anaphylaxis in SLIT-tablet trials using SMQ searches and case definitions of anaphylaxis adopted from the National Institute of Allergy and Infectious Disease. The SMQ search tool contained 2 criteria including treatment-emergent adverse events (AEs): (1) narrow MedDRA terms related to anaphylaxis and (2) all AEs with broad MedDRA terms from at least 2 of 3 categories (respiratory/skin/cardiovascular) occurring on the same day. Criteria were applied to a pooled data set of all subjects from 48 timothy grass, ragweed, house dust mite, and tree SLIT-tablet trials (SLIT-tablet, N= 8200; placebo, N= 7033). Additional search strategies were any treatment-emergent AE with MedDRA preferred term "hypersensitivity" and epinephrine administrations. Identified potential cases underwent blinded independent medical expert review. Nonanaphylaxis cases were designated local AEs or mild to moderate systemic reactions. Using the SMQ search tool and after subsequent medical review, 8 anaphylaxis cases were identified; 3 were considered treatment-related, resulting in a proportion of anaphylaxis cases/subject of 0.02% (2 of 8200) with SLIT-tablet and 0.01% (1 of 7033) with placebo. One additional anaphylaxis case related to SLIT-tablet was identified by the preferred term "hypersensitivity." The 3 anaphylaxis cases associated with SLIT-tablet treatment were not life-threatening. The epinephrine administration rate was 17 of 8200 (0.2%) with SLIT-tablet treatment and 2 of 7033 (0.03%) with placebo. SMQ search criteria for identifying potential anaphylaxis related to SLIT were developed. Anaphylaxis was rare for SLIT-tablets.

IgE to common food allergens is associated with cardiovascular mortality in the National Health and Examination Survey and the Multi-Ethnic Study of Atherosclerosis

In individuals without symptomatic food allergy, food-specific IgE is considered clinically irrelevant. However, recent studies have suggested that galactose-α-1,3-galactose (alpha-gal) IgE is associated with cardiovascular (CV) disease. We sought to determine whether sensitization to common food allergens is associated with CV mortality. The association between IgE sensitization to foods and CV mortality ascertained to 2019 was examined in the National Health and Examination Survey (NHANES) 2005-2006 and the Wake Forest site of the Multi-Ethnic Study of Atherosclerosis (MESA) cohort; MESA enrolled adults without baseline clinical CV diseases between 2000 and 2002. Total and specific IgE was measured to cow's milk, egg, peanut, shrimp, and a panel of aeroallergens (NHANES), and to cow's milk, alpha-gal, peanut, dust mite, and timothy grass (MESA). Cox proportional hazard models were constructed, adjusting for sex, age, race/ethnicity, smoking, education, and asthma. A total of 4414 adults from NHANES (229 CV deaths) and 960 from MESA (56 CV deaths) were included. In NHANES, sensitization to at least 1 food was associated with higher CV mortality (hazard ratio [HR], 1.7 [95% confidence interval (CI), 1.2-2.4], P= .005). Milk sensitization was particularly associated (HR, 2.0 [95% CI, 1.1-3.8], P= .026), a finding replicated in MESA (HR, 3.8 [95% CI, 1.6-9.1], P= .003). Restricting analyses in NHANES to consumers of the relevant allergen strengthened food sensitization relationships, unmasking shrimp and peanut sensitization as additional risk factors for CV mortality. The finding that food sensitization is associated with increased risk of CV mortality challenges the current paradigm that sensitization without overt allergy is benign. Further research is needed to clarify mechanisms of this association.

Common Pollen Modulate Immune Responses against Viral-Like Challenges in Airway Coculture Model.

Recent research indicates that exposure to pollen increases the risk and severity of respiratory infections, while studies also suggest that it may possess a protective function. Our aim was to investigate how exposure to common pollen modifies airway cells' responses to viral- or bacterial-like challenges and vice versa. Cocultured A549 and THP-1 cells were exposed to three doses of four different pollens (Alnus glutinosa, Betula pendula, Phleum pratense, or Ambrosia artemisiifolia) and subsequently to Toll-like receptor (TLR) ligands mimicking bacterial and viral challenges (TLR3, TLR4, TLR7/8). The stimulation experiment was replicated in reverse order. Toxicological and immunological end points were analyzed. When cells were primed with pollen, especially with grass (P. pratense) or weed (A. artemisiifolia), the ability of cells to secrete cytokines in response to bacterial- and viral-like exposure was decreased. In contrast, cells primed with viral ligand TLR7/8 showed greater cytokine responses against pollen than cells exposed to ligands or pollen alone. Our results suggest that pollen exposure potentially weakens immune reactions to bacterial- or viral-like challenges by modulating cytokine production. They also indicate that TLR7/8-mediated viral challenges could elicit exaggerated immune responses against pollen. Both mechanisms could contribute to the acceleration and complication of infections during the pollen season.

Survey of Sensitization to Common Fungi in an Allergic Dog Population: The Need for Further Focus on Sensitization and Allergy to Fungi in Veterinary Medicine.

Most fungal species are commensals and non-pathogenic to plants, humans, or animals. However, several species of the Alternaria, Aspergillus, Trichophyton, and Microsporum genera are common causes of disease, even for immunocompetent individuals. Besides mucosal damage, fungi may contribute to a skin barrier impairment, favoring sensitization and allergy development. A total of 68 allergic dogs were selected from a veterinary dermatology and allergy outpatient consultation for conditions related to both Malassezia overgrowth and other fungal complications. The allergy diagnosis was made through anamnesis and current clinical criteria, with the involved allergenic species being identified by intradermal tests (IDTs) and allergen-specific immunoglobulin E (sIgE) determination in serum. Dermatophagoides farinae, Dactylis glomerata, and Malassezia pachydermatis showed as the higher sensitization species from house dust mites, grass pollen, and fungi, respectively. Significant correlations at p < 0.05 were found between sensitization to Dactylis glomerata and Phleum pratense grass pollens, Dermatophagoides farinae and Dermatophagoides pteronyssinus, Acarus siro, Tyrophagus putrescentiae, and Lepidoglyphus destructor dust/storage mites, and between fungi like Aspergillus mix and Penicillium or Alternaria alternata. A significant correlation was also found between sensitization to the Aspergillus mix and D. farinae, D. pteronyssinus, or A. siro. Rather severe dermatitis was observed when a positive IDT to Malassezia pachydermatis was found, regardless of the detection of circulating sIgE, allowing us to consider the usefulness of both the IDT and the sIgE for a systematic diagnosis of allergy to fungi.

Skin Prick Automated Test device offers more reliable allergy test results compared to a manual skin prick test.

The skin prick test (SPT) is the gold standard for identifying allergic sensitization in individuals suspected of inhalant allergy. A novel device, SPAT or Skin Prick Automated Test, that enables more standardized allergy testing has been developed. Previous research has shown reduced intra-subject variability of histamine wheals by SPAT. This study aimed to evaluate within-test agreement (% of patients with consistent test results) to detect sensitization to common inhalant allergens when a SPT is executed automated by SPAT or by manual SPT (SPMT) procedure. The 110 volunteers prospectively enrolled underwent both SPAT and SPMT with 3 pricks of house dust mite, timothy grass and birch, 2 pricks of histamine and 1 prick of glycerol. The proportion of consistent (3x positive â€" 3 x negative) and inconsistent (2x positive/negative â€" 1x positive/negative) test results were analysed. The proportion of inconsistent test results was significantly lower in the SPAT compared to the SPMT group. The delta histamine to control pricks was significantly higher in SPAT compared to SPMT group. Coefficient of variation was lower in SPAT compared to SPMT for house dust mite, timothy grass, birch pollen. Visual analogue scale for discomfort was significantly lower in SPAT compared to SPMT group. SPAT showed a 34% reduction in the number of inconsistent test results compared to manual SPT with common inhalant allergens. Patient experience is significantly improved when an allergy test is performed by SPAT compared to a manual SPT.

Biochemical composition changes can be linked to the tolerance of four grassland species under more persistent precipitation regimes

AbstractClimate models suggest that the persistence of summer precipitation regimes (PRs) is on the rise, characterized by both longer dry and longer wet durations. These PR changes may alter plant biochemical composition and thereby their economic and ecological characteristics. However, impacts of PR persistence have primarily been studied at the community level, largely ignoring the biochemistry of individual species. Here, we analyzed biochemical components of four grassland species with varying sensitivity to PR persistence (Holcus lanatus, Phleum pratense, Lychnis flos‐cuculi, Plantago lanceolata) along a range of increasingly persistent PRs (longer consecutive dry and wet periods) in a mesocosm experiment. The more persistent PRs decreased nonstructural sugars, whereas they increased lignin in all species, possibly reducing plant quality. The most sensitive species Lychnis seemed less capable of altering its biochemical composition in response to altered PRs, which may partly explain its higher sensitivity. The more tolerant species may have a more robust and dynamic biochemical network, which buffers the effects of changes in individual biochemical components on biomass. We conclude that the biochemical composition changes are important determinants for plant performance under increasingly persistent precipitation regimes.

PSI-19 A Saccharomyces Cerevisiae-Derived Postbiotic Stimulates in Vitro Volatile Fatty Acid Production and Influences Hindgut Microbial Population Characteristics

Abstract Horses rely on volatile fatty acids (VFA) to provide a source of energy and fermentative end-products for their health and performance. Improvement in VFA production, has been associated in various species with improved feed conversion and availability of nutrients necessary to maintain epithelial cell growth, blood flow, and the normal secretory and absorptive functions of the intestine and positive changes in the microbial ecology of the gut. In this study, we characterized the effect of a dietary Saccharomyces cerevisiae fermentation postbiotic (SCFP; Diamond V, Cedar Rapids, IA) using an in vitro equine intestinal model to estimate the effects on VFA production and microbiome changes in the horse hindgut. Treatments contained inoculated medium containing a predigested blend of alfalfa and timothy hay substrate and a dilution of fresh equine excreta. The test article (SCFP) was evaluated at 150 mg (TEC) and 225 mg (TECP), in addition to a negative control containing inoculated medium alone, and the positive control containing inulin. The full array of treatments and replicates were incubated anaerobically at 37.2 C for 24 h. VFA concentrations were analyzed by gas chromatography and the microbiome was characterized through shotgun sequencing. Both levels of SCFP supported greater (P &amp;lt; 0.05) acetate, propionate, butyrate, and total VFA production versus the negative control. Greater production of acetate, propionate, butyrate and total VFA was observed for TECP compared with the positive control (P &amp;lt; 0.05). Between the two SCFP treatments, TECP promoted more acetate, propionate and total VFA (P &amp;lt; 0.01), and 18.3% more butyrate than TEC. Significant microbiome changes were also observed, with TEC and TECP promoting greater microbiome diversity (P &amp;lt; 0.05) compared with both negative and positive controls. Compared with the negative control, both levels of SCFP influenced an increased abundance (P &amp;lt; 0.05) of lactic acid producers (Veillonella), butyrate producers (Butyricicoccus, Anaerobutyricum), and an increased abundance of multiple Bacteroides species, all known for their enrichment of carbohydrate-degrading enzymes. Interestingly, our data show a distinct effect of inulin in microbial communities by promoting an increased abundance of Streptococcus species. This study provides evidence that a SCFP can stimulate VFA production, and this effect is incremental with the level of administration which could potentially provide gut health benefits in horses.

Seasonal and species variation in raffinose, short‐chain fructan, and long‐chain fructan accumulation in tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) grown in Central Kentucky

AbstractFructans in cool‐season grasses may have some negative effects on equine health. However, they may have positive effects on ruminant performance, and fructans of different lengths appear to be metabolized differently in the rumen. Hence, seasonal variation in fructan concentrations may impact equine and ruminant performance. Long‐chain fructan with degree of polymerization (DP) &gt; 8, short‐chain fructan (DP 4 to 8), raffinose, and three fructan trisaccharides were profiled and quantified in timothy (Phleum pratense L.) cultivar ‘Clair’ and tall fescue (Festuca arundinacea Schreb.) cultivar ‘Cajun II’ harvested in April, June, August, and October of two consecutive years in central Kentucky. Harvest year influenced concentrations of long‐chain fructan (p = .0017). Harvest date influenced species differences in raffinose (p = .0035), which was most abundant in timothy in June, and in 1‐kestose and neokestose (p &lt; .0001), which were most abundant in tall fescue in April. Harvest date influenced species differences in short‐ and long‐chain fructan (p &lt; .0001). Tall fescue had two‐ to three‐fold more short‐chain fructan than timothy in April, August, and October. Timothy had two‐ to five‐fold more long‐chain fructan than tall fescue in April, June, and October. Species choice and weather patterns may have contributed to relatively low concentrations of all the carbohydrates measured in this study. Fermentation or feeding studies could help to determine if the concentrations present could affect equine health or ruminant performance.

Phenotypic Diversity in Domesticated and Wild Timothy Grass, and Closely Related Species for Forage Breeding.

Timothy grass (Phleum pratense L.) is one of the most important forage crops in temperate regions. Forage production, however, faces many challenges, and new cultivars adapted to a changing climate are needed. Wild populations and relatives of timothy may serve as valuable genetic resources in the breeding of improved cultivars. The aim of our study is to provide knowledge about the phenotypic diversity in domesticated (cultivars, breeding lines and landraces) and wild timothy and two closely related species, P. nodosum (lowland species) and P. alpinum, (high altitude species) to identify potential genetic resources. A total of 244 accessions of timothy and the two related species were studied for growth (plant height, fresh and dry weight) and plant development (days to stem elongation, days to booting and days to heading) in the field and in a greenhouse. We found a large diversity in development and growth between the three Phleum species, as well as between the accessions within each species. Timothy showed the highest growth, but no significant difference was found between wild accessions and cultivars of timothy in fresh and dry weight. However, these two groups of accessions showed significant differences in plant development, where timothy cultivars as a group reached flowering earlier than the wild accessions. This suggests that there has not been a strong directional selection towards increased yield during the domestication and breeding of timothy; rather, timothy has been changed for other traits such as earlier heading. Principal component analysis and cluster analysis based on all traits revealed distinct clusters. Accessions falling within the same cluster showed similarities in the development and growth rather than the type of accession. The large diversity found in this study shows the potential of using timothy accessions as genetic resources in crosses with existing cultivars. Also, accessions of P. nodosum with favorable traits can be candidates for the domestication of a novel forage crop, and the high-altitude relative P. alpinum may be a source of genes for the development of more cold and stresstolerant cultivars.