Uterine fluid contains factors inhibiting myeloperoxidase enzymatic activity in mares

peer reviewe

Immunohistochemical expression of Myeloperoxidase in the equine endometrium

editorial reviewe

Comparison of two molecular barcodes for the study of equine strongylid communities with amplicon sequencing

Basic knowledge on the biology and epidemiology of equine strongylid species still needs to be improved to contribute to the design of better parasite control strategies. Nemabiome metabarcoding is a convenient tool to quantify and identify species in bulk samples that could overcome the hurdle that cyathostomin morphological identification represents. To date, this approach has relied on the internal transcribed spacer 2 (ITS-2) of the ribosomal RNA gene, with a limited investigation of its predictive performance for cyathostomin communities. Using DNA pools of single cyathostomin worms, this study aimed to provide the first elements to compare performances of the ITS-2 and a cytochrome c oxidase subunit I (COI) barcode newly developed in this study. Barcode predictive abilities were compared across various mock community compositions of two, five and 11 individuals from distinct species. The amplification bias of each barcode was estimated. Results were also compared between various types of biological samples, i.e., eggs, infective larvae or adults. Bioinformatic parameters were chosen to yield the closest representation of the cyathostomin community for each barcode, underscoring the need for communities of known composition for metabarcoding purposes. Overall, the proposed COI barcode was suboptimal relative to the ITS-2 rDNA region, because of PCR amplification biases, reduced sensitivity and higher divergence from the expected community composition. Metabarcoding yielded consistent community composition across the three sample types. However, imperfect correlations were found between relative abundances from infective larvae and other life-stages for Cylicostephanus species using the ITS-2 barcode. While the results remain limited by the considered biological material, they suggest that additional improvements are needed for both the ITS-2 and COI barcodes

Validation of a serum ELISA test for cyathostomin infection in equines

Cyathostomins are ubiquitous equine nematodes. Infection can result in larval cyathostominosis due to mass larval emergence. Although faecal egg count (FEC) tests provide estimates of egg shedding, these correlate poorly with burden and provide no information on mucosal/luminal larvae. Previous studies describe a serum IgG(T)-based ELISA (CT3) that exhibits utility for detection of mucosal/luminal cyathostomins. Here, this ELISA is optimised/validated for commercial application using sera from horses for which burden data were available. Optimisation included addition of total IgG-based calibrators to provide standard curves for quantification of antigen-specific IgG(T) used to generate a CT3-specific 'serum score' for each horse. Validation dataset results were then used to assess the optimised test's performance and select serum score cut-off values for diagnosis of burdens above 1,000, 5,000 and 10,000 cyathostomins. The test demonstrated excellent performance (Receiver Operating Characteristic Area Under the Curve values >0.9) in diagnosing infection, with >90% sensitivity and >70% specificity at the selected serum score cut-off values. CT3-specific serum IgG(T) profiles in equines in different settings were assessed to provide information for commercial test use. These studies demonstrated maternal transfer of CT3-specific IgG(T) in colostrum to newborns, levels of which declined before increasing as foals consumed contaminated pasture. Studies in geographically distinct populations demonstrated that the proportion of horses that reported as test positive at a 14.37 CT3 serum score (1,000-cyathostomin threshold) was associated with parasite transmission risk. Based on the results, inclusion criteria for commercial use were developed. Logistic regression models were developed to predict probabilities that burdens of individuals are above defined thresholds based on the reported serum score. The models performed at a similar level to the serum score cut-off approach. In conclusion, the CT3 test provides an option for veterinarians to obtain evidence of low cyathostomin burdens that do not require anthelmintic treatment and to support diagnosis of infection

Comparison of flying and soil invertebrates' biodiversity on meadows with or without horse grazing

By grazing preferentially some spots, horses create patches of short grass and tall vegetation in which they concentrate their dungs. This leads to habitat heterogeneity that could increase grassland animal biodiversity. This pilot study aimed to test a method to compare, using non-lethal protocols, invertebrates' biodiversity on meadows undergoing or not horse grazing. This 2-years study was performed in our experimental farm facilities using one-hectare paddocks with meadows 5-years-old and similar bordering environment. Two paddocks were grazed from April to November by 6 pony mares each and 2 paddocks were not grazed. For bees monitoring, 2 trap nests of 32 tubes each were placed at paddocks' edge. Nest occupancy was monitored by counting sealed tubes from March to October. Butterflies were monitored once per month from May to September by recording all butterflies in a 5×5×5m cube around the observer during a 10-min long transect. To monitor soil invertebrates, 3 wooden boards of 30×50cm were laid on the ground, 2 at the edge and 1 at the center of the paddock. Once per month from March to November all invertebrates present under the board were identified and assigned to 3 categories: predators (carabid beetle and spiders), herbivores (mollusks), and detritivores (earthworms, millipedes, woodlouse, ants). The nests were occupied by solitary bees in the genus Osmia and Megachile, and the number of sealed tubes was different between grazed and non-grazed meadows. Butterflies from Hesperiidae, Pieridae, Lycaenidae and Nymphalidae families were observed. Their abundance and diversity tend to be higher in grazed meadows. The abundance of predators was similar between grazed and non-grazed meadows, but the abundance of mollusks and detritivores tend to be different. These tendencies should be considered with caution because of the short period of observation and the limited number of meadows included in the study. Collection of additional data is in progress to consolidate the data and confirm the impact of horse grazing. In spite of this limitation, this pilot study shows that wild biodiversity can be studied using non-lethal protocols on horse-grazed meadows and that horse grazing may influence some invertebrates groups

Le suprefact à faible dose : une alternative prometteuse pour induire l'ovulation chez la jument

National audienc

Production de jeunes embryons équins par maturation, fécondation et culture in vitro

National audienc

Éditorial

Dix ans (et quelques mois maintenant) que Métropoles a vu le jour ! Pensée comme la première revue électronique francophone d’études urbaines critiques, dans une perspective sur laquelle l’introduction et la première partie du numéro reviennent de manière rétrospective et réflexive, Métropoles était un vrai pari. D’abord parce que le paysage de l’édition scientifique n’avait pas encore basculé vers l’électronique. Ensuite parce que les cloisonnements scientifiques paraissaient suffisamment an..