Exposure assessment of cattle via roughages to plants producing compounds of concern

Do Poisonous Plants in Pastures Communicate Their Toxicity? Meta-Study and Evaluation of Poisoning Cases in Central Europe

One of the possible roles of secondary plant metabolites, including toxins, is facilitating plant-animal communication. Lethal cases of pasture poisoning show that the message is not always successfully conveyed. As the focus of poisoning lies in the clinical aspects, the external circumstances of pasture poisoning are widely unknown. To document poisoning conditions in cattle, sheep, goats, and horses on pastures and to compile a checklist of plants involved in either poisoning or co-existence (zero poisoning), published case reports were evaluated as primary sources. The number of affected animal individuals was estimated within abundance classes from 0 to more than 100. The checklist of poisonous plants comprised 52 taxa. Of these, 13 taxa were deemed safe (no reference was found indicating poisoning), 11 taxa were associated with evidence-based zero poisoning (positive list), and 28 taxa were associated with poisoning (negative list). Nine plant taxa caused poisoning in more than 100 animal individuals. Zero poisoning accounted for 40% and poisoning accounted for 60% of a total of 85 cases. Poisoning was most often associated with a limited choice of feed (24.7%), followed by overgrazing (12.9%), seasonally scarce feed (10.6%), and co-ingestion of grass (4.7%). Hunger interferes with plant-animal co-existence, while zero poisoning improves it. In conclusion, poisonous plants in pastures may communicate their toxicity if the animals have enough alternative feed plants. An individual animal might utterly perceive the communication of toxicity by the plant species but be forced to ignore the message owing to a limited choice of feed options.

HILIC HPLC-ESI-MS/MS identification and quantification of the alkaloids from the genus Equisetum

INTRODUCTION

The plant family Equisetaceae (Equisetopsida, Monilophyta; common name: horsetails) is part of an ancient group of spore producing plants. Today, Equisetum is the only surviving genus comprising 15 species in two subgenera (Equisetum and Hippochaete). Several unique alkaloids are described to occur in this genus, so far there is very little data on the occurrence and the amount of those alkaloids for the different species.

OBJECTIVE

To establish an extraction method and an analytical method to detect and quantify the relevant Equisetum-type alkaloids and to create a quantitative data set on the alkaloid content of all Equisetum species worldwide.

METHODOLOGY

Hydrophilic interaction liquid chromatography high-performance liquid chromatography tandem mass spectrometry (HILIC HPLC-MS/MS) in electrospray ionisation (ESI) positive mode was used to analyse and quantify the alkaloid content of 68 Equisetum samples.

RESULTS

The presence of nicotine in at least one sample of each Equisetum species could be demonstrated. The total nicotine amount rarely exceeded 250 μg/kg and 50 μg/kg for the subgenus Equisetum and Hippochaete, respectively. Besides nicotine, Equisetum-type alkaloids (mainly palustrine and palustridiene) were only detected in three species, namely E. palustre, E. bogotense and E. giganteum. For E. giganteum, palustridiene was detected at levels around the limit od detection (LoD) (25 μg/kg), whereas in E. palustre and E. bogotense, both alkaloids (palustrine and palustridiene) were detected at much higher levels (20-800 mg/kg).

CONCLUSIONS

All Equisetum species occurring worldwide were successfully subjected to a detailed qualitative and quantitative alkaloid analysis using a newly developed HILIC-HPLC-ESIpos-MS/MS approach. The data set can be used to distinguish different Equisetum-chemotypes.

Bridging legal requirements and analytical methods: a review of monitoring opportunities of animal proteins in feed

Availability and safety of food ranks among the basic requirements for human beings. The importance of the food producing sector, inclusive of feed manufacturing, demands a high level of regulation and control. This paper will present and discuss the relationships in the triangle of legislation, the background of hazards with a biological nature, and opportunities for monitoring methods, most notable for prion-based diseases as primary issue. The European Union legislation for prevention of prion-based diseases since 2000 is presented and discussed. The definitions and circumscriptions of groups of species will be analysed in the view biological classification and evolutionary relationships. The state of the art of monitoring methods is presented and discussed. Methods based on visual markers (microscopy), DNA-based methods (PCR), protein-based methods (ELISA, mass spectroscopy, proteomics), near infrared oriented methods and combinations thereof are being evaluated. It is argued that the use in legislation of non-homogeneous groups of species in a biological sense will hamper the optimal design of monitoring methods. Proper definitions are considered to act as bridges between legal demands and suitable analytical methods for effective monitoring. Definitions including specified groups of species instead of single species are more effective for monitoring in a range of cases. Besides the desire of precise circumscription of animal groups targeted by legislation, processed products need well defined definitions as well. Most notable examples are blood versus blood products, and hydrolysis of several types of material. The WISE principle for harmonising the design of legislation and of analytical methods is discussed. This principle includes the elements Witful (reasonable legal principles), Indicative (clear limits between prohibition and authorisation), Societal demands (public health, environment, economy), and Enforceable (presence of suited monitoring methods) in order to promote a balanced effort for reaching the desired level of safety in the food production chain.

Accumulation and depletion of indospicine in calves (Bos taurus) fed creeping indigo (Indigofera spicata)

Prolonged consumption of Indigofera pasture plants can cause both hepatotoxicosis and reproductive losses in grazing animals with the responsible toxin indospicine forming persistent tissue residues. Separate accumulation and depletion feeding trials were undertaken in calves fed Indigofera spicata (3 mg indospicine/kg bodyweight) to ascertain the appearance and elimination of indospicine from various tissues. In the accumulation trial indospicine concentrations increased throughout the 42-day feeding period with maximum levels of 15 mg/L in plasma and 19 and 33 mg/kg in liver and muscle, respectively. In the depletion trial, calves were fed I. spicata for 35 days, after which the plant was withdrawn from the diet. The rate of elimination was relatively slow with estimates of half-life being 31, 25 and 20 days for muscle, liver and plasma, respectively. Indospicine levels measured in bovine tissues in this trial are comparable with levels in horsemeat and camel meat reported to cause fatal hepatoxicity in dogs, a species known to be susceptible to this toxin. The persistence of indospicine residues in bovine tissues and the widespread distribution of Indigofera species in tropical and sub-tropical grazing lands warrant further investigation, as indospicine has been established as causing reproductive losses and likely contributes to calf losses in these regions.

Determination of pyrrolizidine alkaloids in selected feed materials with gas chromatography-mass spectrometry

1,2-Dehydropyrrolizidine alkaloids are known to be toxic to many animals and humans. To provide safety of feeds a method based on gas chromatography-mass spectrometry enabling the determination of a content of 1,2-unsaturated PAs in feed materials was developed. After extraction with aqueous solution of HCl and purification of the extract, 1,2-unsaturated alkaloids are reduced to their common backbone structures and subsequently derivatised with heptafluorobutyric anhydride (HFBA). The method was validated according to SANTE/11945/2015. All received parameters are consistent with the document requirements as recovery of a final compound retronecine derivative was from 81.8% to 94.4% when retrosine was used for spiking and from 72.7% to 85.5% when retrorsine N-oxide was spiked. The repeatability was calculated as relative standards deviation and ranged from 7.5% to 14.4%, for N-oxide was from 7.9% to 15.4%. The reproducibility was in the range from 14.2% to 16.3% and from 17.0% to 18.1% for free base and N-oxide respectively. The limit of quantification was determined as 10 µg kg^-1. Good linearity of the method was obtained with coefficient of determination R² > 0.99. The method was applied to 35 silage and two hay samples analysis.

New feed ingredients: the insect opportunity

In the framework of sustainability and a circular economy, new ingredients for feed are desired and, to this end, initiatives for implementing such novel ingredients have been started. The initiatives include a range of different sources, of which insects are of particular interest. Within the European Union, generally, a new feed ingredient should comply with legal constraints in terms of 'yes, provided that' its safety commits to a range of legal limits for heavy metals, mycotoxins, pesticides, contaminants, pathogens etc. In the case of animal proteins, however, a second legal framework applies which is based on the principle 'no, unless'. This legislation for eradicating transmissible spongiform encephalopathy consists of prohibitions with a set of derogations applying to specific situations. Insects are currently considered animal proteins. The use of insect proteins is a good case to illustrate this difference between a positive, although restricted, modus and a negative modus for allowing animal proteins. This overview presents aspects in the areas of legislation, feed safety, environmental issues, efficiency and detection of the identity of insects. Use of insects as an extra step in the feed production chain costs extra energy and this results in a higher footprint. A measure for energy conversion should be used to facilitate the comparison between production systems based on cold- versus warm-blooded animals. Added value can be found by applying new commodities for rearing, including but not limited to category 2 animal by-products, catering and household waste including meat, and manure. Furthermore, monitoring of a correct use of insects is one possible approach for label control, traceability and prevention of fraud. The link between legislation and enforcement is strong. A principle called WISE (Witful, Indicative, Societal demands, Enforceable) is launched for governing the relationship between the above-mentioned aspects.

Poisonous or non-poisonous plants? DNA-based tools and applications for accurate identification

Plant exposures are among the most frequently reported cases to poison control centres worldwide. This is a growing condition due to recent societal trends oriented towards the consumption of wild plants as food, cosmetics, or medicine. At least three general causes of plant poisoning can be identified: plant misidentification, introduction of new plant-based supplements and medicines with no controls about their safety, and the lack of regulation for the trading of herbal and phytochemical products. Moreover, an efficient screening for the occurrence of plants poisonous to humans is also desirable at the different stages of the food supply chain: from the raw material to the final transformed product. A rapid diagnosis of intoxication cases is necessary in order to provide the most reliable treatment. However, a precise taxonomic characterization of the ingested species is often challenging. In this review, we provide an overview of the emerging DNA-based tools and technologies to address the issue of poisonous plant identification. Specifically, classic DNA barcoding and its applications using High Resolution Melting (Bar-HRM) ensure high universality and rapid response respectively, whereas High Throughput Sequencing techniques (HTS) provide a complete characterization of plant residues in complex matrices. The pros and cons of each approach have been evaluated with the final aim of proposing a general user's guide to molecular identification directed to different stakeholder categories interested in the diagnostics of poisonous plants.

A manifesto for the valorization of wild edible plants

ETHNOPHARMACOLOGICAL RELEVANCE

Wild foods constitute an essential component of people's diets around the world, but despite their widespread use and their cultural importance, wild edible plants (WEPs) lack recognition as significant contributors to the human diet in developed countries.

MATERIALS AND METHODS

We stimulate national and international bodies dealing with food and agriculture, to increase their attention and investments on WEPs, leveraging the results of scientific investigation, enhancing the link between in situ conservation strategies and sustainable use of plant genetic diversity.

RESULTS AND CONCLUSIONS

WEPs should be reconsidered throughout their value chain, capturing their important socio-cultural, health, and economic benefits to indigenous and local communities and family farmers who are engaged in their production and wild-harvesting.

Alkaloid-Containing Plants Poisonous to Cattle and Horses in Europe

Alkaloids, nitrogen-containing secondary plant metabolites, are of major interest to veterinary toxicology because of their occurrence in plant species commonly involved in animal poisoning. Based on epidemiological data, the poisoning of cattle and horses by alkaloid-containing plants is a relatively common occurrence in Europe. Poisoning may occur when the plants contaminate hay or silage or when forage alternatives are unavailable. Cattle and horses are particularly at risk of poisoning by Colchicum autumnale (meadow saffron), Conium maculatum (poison hemlock), Datura stramonium (jimson weed), Equisetum palustre (marsh horsetail), Senecio spp. (ragwort and groundsel) and Taxus baccata (European yew). This review of poisonous alkaloid-containing plants describes the distribution of these plants, conditions under which poisoning occurs, active toxic principles involved and subsequent clinical signs observed.