Endophyte infection of tall fescue and the impact of climatic factors on ergovaline concentrations in field crops cultivated in southern France

Risks for animal health related to the presence of ergot alkaloids in feed

The European Commission requested EFSA to provide an update of the 2012 Scientific Opinion of the Panel on Contaminants in the Food Chain (CONTAM) on the risks for animal health related to the presence of ergot alkaloids (EAs) in feed. EAs are produced by several fungi of the Claviceps and Epichloë genera. This Opinion focussed on the 14 EAs produced by C. purpurea (ergocristine, ergotamine, ergocornine, α- and β-ergocryptine, ergometrine, ergosine and their corresponding 'inine' epimers). Effects observed with EAs from C. africana (mainly dihydroergosine) and Epichloë (ergovaline/-inine) were also evaluated. There is limited information on toxicokinetics in food and non-food producing animals. However, transfer from feed to food of animal origin is negligible. The major effects of EAs are related to vasoconstriction and are exaggerated during extreme temperatures. In addition, EAs cause a decrease in prolactin, resulting in a reduced milk production. Based on the sum of the EAs, the Panel considered the following as Reference Points (RPs) in complete feed for adverse animal health effects: for pigs and piglets 0.6 mg/kg, for chickens for fattening and hens 2.1 and 3.7 mg/kg, respectively, for ducks 0.2 mg/kg, bovines 0.1 mg/kg and sheep 0.3 mg/kg. A total of 19,023 analytical results on EAs (only from C. purpurea) in feed materials and compound feeds were available for the exposure assessment (1580 samples). Dietary exposure was assessed using two feeding scenarios (model diets and compound feeds). Risk characterisation was done for the animals for which an RP could be identified. The CONTAM Panel considers that, based on exposure from model diets, the presence of EAs in feed raises a health concern in piglets, pigs for fattening, sows and bovines, while for chickens for fattening, laying hens, ducks, ovines and caprines, the health concern related to EAs in feed is low.

Synthesis, Evaluation, and Characterization of an Ergotamine Imprinted Styrene-Based Polymer for Potential Use as an Ergot Alkaloid Selective Adsorbent

Alkaloid toxicities negatively impact livestock health and production. To assess alkaloid occurrences, adsorbent technologies may offer effective means to their extraction and isolation from a complex feed matrix. In this study, molecularly imprinted polymers (MIPs) were synthesized and evaluated for their specificity of binding to various ergot alkaloids. Co-polymers of styrene and hydroxyethyl methacrylate were synthesized in the absence or presence of an ergotamine (ETA) template, yielding non-imprinted polymer (NIP) and molecularly imprinted polymer (MIP), respectively. The influence of parameters such as pH, temperature, and initial concentration on the adsorption of ergot alkaloids was evaluated along with their application as solid phase extraction materials. Chemical and morphological properties were characterized. Adsorption was generally greater for MIP compared to NIP. Cross-reactivity with related alkaloids existed due to similarities in structure and functional groups and was dependent on the type and concentration of alkaloid and polymer type (alkaloid type × concentration × product; P < 0.05). The pH of the medium had no influence on the binding properties of polymers toward ETA within a pH range of 2-10. Binding was independent of temperature between 36 and 42 °C. When kinetics of adsorption were evaluated, the Langmuir isotherm had a better fit (R ² > 0.95) to adsorption equilibrium data than the Freundlich equation. The maximum amounts adsorbed (Q _o) from the Langmuir model were 8.68 and 7.55 μM/g for MIP and NIP, respectively. Fourier transform infrared, scanning and tandem electron microscopy, and Brunauer-Emmett-Teller analysis confirmed a highly porous MIP structure with a greater surface area compared to NIP. Binding characteristics evaluated with computational strategy using molecular docking experiments and in vitro in a complex media (rumen fluid) indicated a stronger ETA adsorption by the tested composition selected among other polymeric materials and affinity of MIP compared with NIP. This study suggested the possible utility of MIP as a solid phase extraction sorbent for applications in analytical chemistry or sensing devices tailored to track ergot alkaloid incidence and the fate of those alkaloids in complex ruminal digestive samples.

Epichloë Endophyte Infection rates and Alkaloid Content in Commercially Available Grass Seed Mixtures in Europe

Fungal endophytes of the genus Epichloë live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichloë infected grasses, the inclusion of Epichloë in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichloë infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichloë endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichloë infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichloë festucae var. lolii infecting Lolium perenne. As Epichloë infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichloë infection status or avoiding Epichloë infected seed mixtures.

Immunochemical Analysis of Paxilline and Ergot Alkaloid Mycotoxins in Grass Seeds and Plants

Limited availability of toxin standards for lolitrem B and ergovaline impedes routine control of grasses for endophyte toxins. This study aimed at assessing the applicability of an enzyme immunoassay (EIA) for the indole-diterpene mycotoxin paxilline, in combination with a generic EIA for ergot alkaloids, as alternative parameters for screening purposes. Analysis of grass seeds and model pastures of four different grass species showed that both EIAs yielded highly positive results for paxilline and ergot alkaloids in perennial ryegrass seeds. Furthermore, evidence for natural occurrence of paxilline in grass in Germany was obtained. High performance liquid chromatography-tandem mass spectrometry analysis qualitatively confirmed the paxilline EIA results but showed that paxilline analogues 1'-O-acetylpaxilline and 13-desoxypaxilline were the predominant compounds in seeds and grass. In the absence of easily accessible reference standards for specific analysis of some major endophyte toxins, analysis of paxilline and ergot alkaloids by EIA may be suitable substitute parameters. The major advantage of this approach is its ease of use and speed, providing an analytical tool which could enhance routine screening for endophyte toxins in pasture.

Toxicity of endophyte-infected ryegrass hay containing high ergovaline level in lactating ewes

The symbiotic association of var. (formerly named ) with perennial ryegrass () leads to the production of ergovaline (EV) and lolitrem B (LB) that are toxic for livestock. The objectives of this study were to determine the effects of feeding endophyte-infected ryegrass (SE+) hay on 16 lactating ewes (BW 80 ± 10 kg) in comparison with endophyte-free ryegrass (SE-) hay to investigate the putative mechanisms of action of EV and LB and to evaluate their persistence in milk and animal tissues. The mean EV and LB concentrations in SE+ hay were 851 and 884 μg/kg DM, respectively, whereas these alkaloids were below the limit of detection in SE- hay. No effect of SE+ was observed on animal health and skin temperature whereas prolactin decreased and significant differences between hays were observed from d 7 to 28 of the study ( < 0.03) but had no effect on milk production. Hematocrit and biochemical analyses of plasma revealed no significant difference between SE+ and SE-, whereas cortisol concentration differed significantly on d 28 ( = 0.001). Measurement of oxidative damage and antioxidant enzyme activities in plasma, liver, and kidneys revealed a slight increase in some enzyme activities involved in defense against oxidative damage in the SE+ fed ewes. Slight variations in the activities of hepatic and kidney flavin monooxygenase enzymes were observed, whereas in the kidney, glutathione -transferase activity decreased significantly ( = 0.002) in the SE+ fed ewes, whereas uridine diphosphate glucuronosyltransferase activity increased ( = 0.001). After 28 d of exposure of ewes to the SE+ hay, low EV and LB concentrations were measured in tissues. The highest concentration of EV was observed in the liver (0.68 μg/kg) whereas fat contained the highest concentration of LB (2.39 μg/kg). Both toxins were also identified at the trace level in milk.

Lolitrem B and Indole Diterpene Alkaloids Produced by Endophytic Fungi of the Genus Epichloë and Their Toxic Effects in Livestock

Different group of alkaloids are produced during the symbiotic development of fungal endophytes of the genus Epichloë in grass. The structure and toxicity of the compounds vary considerably in mammalian herbivores and in crop pests. Alkaloids of the indole-diterpene group, of which lolitrem B is the most toxic, were first characterized in endophyte-infected perennial ryegrass, and are responsible for “ryegrass staggers.” Ergot alkaloids, of which ergovaline is the most abundant ergopeptide alkaloid produced, are also found in ryegrass, but generally at a lower rate than lolitrem B. Other alkaloids such as lolines and peramine are toxic for crop pests but have weak toxicological properties in mammals. The purpose of this review is to present indole-diterpene alkaloids produced in endophyte infected ryegrass from the first characterization of ryegrass staggers to the determination of the toxicokinetics of lolitrem B and of their mechanism of action in mammals, focusing on the different factors that could explain the worldwide distribution of the disease. Other indole diterpene alkaloids than lolitrem B that can be found in Epichloë infected ryegrass, and their tremorgenic properties, are presented in the last section of this review.

Alkaloid Quantities in Endophyte-Infected Tall Fescue are Affected by the Plant-Fungus Combination and Environment

Many grass species are symbiotic with systemic, vertically-transmitted, asymptomatic Epichloë endophytic fungi. These fungi often produce alkaloids that defend the host against herbivores. We studied how environmental variables affect alkaloids in endophyte-infected tall fescue (Schedonorus phoenix) from three Northern European wild origins and the widely planted US cultivar ‘Kentucky-31’ (KY31). The plants were grown in identical common garden experiments in Finland and Kentucky for two growing seasons. Plants were left as controls (C) or given water (W), nutrient (N) or water and nutrient (WN) treatments. For 8–10 replications of each plant origin and treatment combination in both experiments, we analyzed ergot alkaloids, lysergic acid, and lolines. In Finland, tall fescue plants produced 50 % more ergot alkaloids compared to plants of the same origin and treatments in Kentucky. Origin of the plants affected the ergot alkaloid concentration at both study sites: the wild origin plants produced 2–4 times more ergot alkaloids than KY31, but the ergot alkaloid concentration of KY31 plants was the same at both locations. Overall lysergic acid content was 60 % higher in plants grown in Kentucky than in those grown in Finland. Nutrient treatments (N, WN) significantly increased ergot alkaloid concentrations in plants from Finland but not in plants from Kentucky. These results suggest that the success of KY31 in US is not due to selection for high ergot alkaloid production but rather other traits associated with the endophyte. In addition, the environmental effects causing variation in alkaloid production of grass-endophyte combinations should be taken into account when using endophyte-infected grasses agriculturally.

Variation in Alkaloid Production from Genetically Diverse Lolium Accessions Infected with Epichloë Species

Widespread infection of Epichloë occultans in annual ryegrass in Australia suggests that infection provides its weedy host, Lolium rigidum, some ecological advantage. Initial studies determined the distribution and profiles of known Epichloë alkaloids (epoxy-janthitrems, ergovaline, lolines, lolitrem B, and peramine) in plant extracts using a combination of GC-FID and HPLC techniques utilizing a single accession of Australian L. rigidum. However, the lolines N-acetylnorloline (NANL) and N-formylloline (NFL) were the only alkaloids detected and were highly concentrated in the immature inflorescences of mature plants. Additional glasshouse studies subjected a wide range of Australian L. rigidum haplotypes and international annual Lolium accessions to a suite of analyses to determine alkaloid levels and profiles. Again, NFL and NANL were the key lolines produced, with NFL consistently predominating. Considerable variation in alkaloid production was found both within and between biotypes and accessions evaluated under identical conditions, at the same maturation stage and on the same tissue type. The pyrrolopyrazine alkaloid peramine was also present in 8 out of 17 Australian biotypes of L. rigidum and 7 out of 33 international accessions infected with Epichloë spp.; the highest peramine concentrations were observed in seed extracts from L. rigidum collected from Australia. This study represents the first report of alkaloids from a geographically diverse collection of annual ryegrass germplasm infected with Epichloë spp. when grown under identical controlled conditions.

Ergot alkaloids produced by endophytic fungi of the genus Epichloë

The development of fungal endophytes of the genus Epichloë in grasses results in the production of different groups of alkaloids, whose mechanism and biological spectrum of toxicity can differ considerably. Ergot alkaloids, when present in endophyte-infected tall fescue, are responsible for "fescue toxicosis" in livestock, whereas indole-diterpene alkaloids, when present in endophyte-infected ryegrass, are responsible for "ryegrass staggers". In contrast, peramine and loline alkaloids are deterrent and/or toxic to insects. Other toxic effects in livestock associated with the consumption of endophyte-infected grass that contain ergot alkaloids include the "sleepy grass" and "drunken horse grass" diseases. Although ergovaline is the main ergopeptine alkaloid produced in endophyte-infected tall fescue and is recognized as responsible for fescue toxicosis, a number of questions still exist concerning the profile of alkaloid production in tall fescue and the worldwide distribution of tall fescue toxicosis. The purpose of this review is to present ergot alkaloids produced in endophyte-infected grass, the factors of variation of their level in plants, and the diseases observed in the mammalian species as relate to the profiles of alkaloid production. In the final section, interactions between ergot alkaloids and drug-metabolizing enzymes are presented as mechanisms that could contribute to toxicity.

Ergovaline and lolitrem B concentrations in perennial ryegrass in field culture in southern France: distribution in the plant and impact of climatic factors

Perennial ryegrass (Lolium perenne) infected by Epichloë festucae var. lolii contains alkaloids that are responsible for toxicosis in several countries, but few cases are reported in Europe. Lolitrem B is generally the most abundant alkaloid and is recognized to be responsible for livestock staggers, whereas ergovaline is less frequently documented in perennial ryegrass. Lolitrem B and ergovaline were monitored over a three-year period in endophyte-infected perennial ryegrass 'Samson' sown in southern France. Alkaloid concentrations were strongly influenced by the stage of maturity of the plant; maximum concentrations were always measured at the fully ripe stage. Over the three years of analysis, variations in lolitrem B in the whole plant at the fully ripe stage were low (from 1296 to maximum 1871 μg/kg dry matter), whereas ergovaline varied considerably (from 526 to 2322 μg/kg dry matter), suggesting that abiotic factors play a key role in determining ergovaline levels in endophyte-infected perennial ryegrass.