Grazing livestock are exposed to terrestrial cyanobacteria

Abstract

While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-015-0143-x) contains supplementary material, which is available to authorized users.

Occurrence of β-N-methylamino-l-alanine (BMAA) and Isomers in Aquatic Environments and Aquatic Food Sources for Humans

“…The DAB (also named DABA) is a component of some bacteria wall (e.g., genus Corynebacterium ) [ 70 ] or actinomycetes (e.g., Agrococcus jenensis ) [ 71 ]. The presence of DAB has been also specifically reported in angiosperm species such as Lathyrus latifolius or Brassica oleracea [ 19 , 28 ] as well as in aquatic [ 32 ] or terrestrial [ 72 ] plants. DAB was reported for the first time in 2008 in the cyanobacteria Calothrix sp.…”

Sedimentary DNA Reveals Cyanobacterial Community Diversity over 200 Years in Two Perialpine Lakes

“…Recent evidence from whole-genome sequencing confirmed that Melainabacteria constitute a class within the Cyanobacteria phylum because the two groups share common ancestral traits, such as the cell envelope structure and the presence of putative circadian rhythms (54). Taxa within this group have been detected in various environments, including groundwater, drinking water and wastewater treatment plants (54,55), terrestrial plants, and animal guts (56). To our knowledge, their presence has not been previously reported in lakes.…”

Transfer of developmental neurotoxin β- N -methylamino- l -alanine (BMAA) via milk to nursed offspring: Studies by mass spectrometry and image analysis

“…Studies are warranted to determine whether breastfed infants may be exposed to BMAA via mothers' milk. Likewise, as cyanobacteria may be present in fields used for livestock grazing or fed to livestock directly (Šimkus et al, 2007, Kulpys et al, 2009, Christaki et al, 2012, McGorum et al, 2015, concentrations of BMAA should be determined in cows' milk.…”

“…BMAA is a non-protein amino acid produced by cyanobacteria, dinoflagellates and diatoms (Cox et al, 2005, Jiang et al, 2014a and detected in aquatic organisms, including sharks and bony fish, crustaceans and mussels that are consumed by humans (Brand et al, 2010, Jonasson et al, 2010, Mondo et al, 2012, Field et al, 2013, Masseret et al, 2013, Banack et al, 2014, Jiang et al, 2014b, Lage et al, 2014, Banack et al, 2015, Lage et al, 2015, Reveillon et al, 2015. BMAA has also been reported to be present in brains of Alzheimer's disease patients and ALS patients (Murch et al, 2004b), a finding that was replicated by an independent team using the same techniques (Pablo et al, 2009), while another team using different techniques failed to detect BMAA (Snyder et al, 2009).…”