Omics technologies provide new insights into the molecular physiopathology of equine osteochondrosis

Background: Osteochondrosis (OC(D)) is a juvenile osteo-articular disorder affecting several mammalian species. In horses, OC(D) is considered as a multifactorial disease and has been described as a focal disruption of endochondral ossification leading to the development of osteoarticular lesions. Nevertheless, OC(D) physiopathology is poorly understood. Affected horses may present joint swelling, stiffness and lameness. Thus, OC(D) is a major concern for the equine industry. Our study was designed as an integrative approach using omics technologies for the identification of constitutive defects in epiphyseal cartilage and/or subchondral bone associated with the development of primary lesions to further understand OC(D) pathology. This study compared samples from non-affected joints (hence lesion-free) from OC(D)-affected foals (n = 5, considered predisposed samples) with samples from OC-free foals (n = 5) considered as control samples. Consequently, results are not confounded by changes associated with the evolution of the lesion, but focus on altered constitutive molecular mechanisms. Comparative proteomics and micro computed tomography analyses were performed on predisposed and OC-free bone and cartilage samples. Metabolomics was also performed on synovial fluid from OC-free, OC(D)-affected and predisposed joints. Results: Two lesion subtypes were identified: OCD (lesion with fragment) and OC (osteochondral defects). Modulated proteins were identified using omics technologies (2-DE proteomics) in cartilage and bone from affected foals compare to OC-free foals. These were associated with cellular processes including cell cycle, energy production, cell signaling and adhesion as well as tissue-specific processes such as chondrocyte maturation, extracellular matrix and mineral metabolism. Of these, five had already been identified in synovial fluid of OC-affected foals: ACTG1 (actin, gamma 1), albumin, haptoglobin, FBG (fibrinogen beta chain) and C4BPA (complement component 4 binding protein, alpha). Conclusion: This study suggests that OCD lesions may result from a cartilage defect whereas OC lesions may be triggered by both bone and cartilage defects, suggesting that different molecular mechanisms responsible for the equine osteochondrosis lesion subtypes and predisposition could be due to a defect in both bone and cartilage. This study will contribute to refining the definition of OC(D) lesions and may improve diagnosis and development of therapies for horses and other species, including humans

Comparing the effects of horse grazing alone or with cattle on horse parasitism and vegetation use in a mesophile pasture

International audienceMixing different herbivore species is assumed to increase vegetation use because of the complementarity of their feeding choices and to reduce animal parasite burden through the dilution effect. Here, we compare the effects of mixed horse-cattle grazing and monospecific horse grazing (1.4 LU/ha) on animal foraging behaviour, sward characteristics and horse parasitism in a mesophile grassland of central France. In both treatments, animals were stocked alternately on two subplots with rotation lengths between 15 and 21 days according to season. The horses quickly acclimated to the cattle, and very few agonistic interactions were observed between them. All the horses selected short (<= 4 cm) and intermediate (5-8 cm) high-quality regrowths and avoided reproductive and dead herbage areas contaminated by their faeces as a consequence of their latrine behaviour. Cattle, which are more constrained by plant height, selected intermediate and tall vegetative swards. However, the alternate stocking of animals also provided them with high-quality regrowth on the shortest patches. Consequently, the cattle used these short patches proportionally to their availability while avoiding reproductive and dead herbage areas. We assume this limited their consumption of infective cyathostome larvae, which are concentrated close to horse dung. Moreover, co-grazing horses and cattle did not reduce sward structural heterogeneity and thus did not enhance overall herbage quality. We conclude that rather than considering mixed grazing as a turn-key solution, its management needs to be adapted to support the complementarity of horse and cattle dietary choices and thus provide the expected benefits of multi-species grazing

Co-grazing horses and cattle requires appropriate management to provide its expected benefits

International audienc

Management of the pregnant mare and long-term consequences on the offspring

Members of COST Action FA0702 GEMINI "Maternal interaction with gametes and embryo", "FA1201 EPICONCEPT "Epigenetics and periconception environment", and BM 1308 SALAAM " Sharing advances on large animal models"International audienceThe study of early developmental conditioning of health and disease in adulthood is particularly relevant in the horse, which is bred mainly to perform in demanding sport challenges. On the basis of this concept, the management of the broodmare could be considered an effective means to produce animals with the desired features. Knowledge on the Developmental Origins of Health and Disease in the equine species remains relatively scarce, with some experimental studies and one single epidemiologic study. Data highlight the determinant role of the maternal environment for postnatal body conformation, immune response, energy homeostasis, osteoarticular status and thyroidal, adrenocortical, and cardiovascular functions of the foal. Most research, however, focuses on the first months/years after birth. Long-term effects on the adult horse phenotype have not been investigated so far

Effet de l'obésité maternelle sur la qualité du lait en acides gras au cours de la lactation chez la jument

Contexte: A l'état naturel, le cheval, qui est un monogastrique, s'alimente principalement d'herbes et de fourrage, presque 16 heures par jour. Aujourd'hui, l'alimentation du cheval de sport ou de loisirs a évolué et les rations sont apportées sous forme de repas à heure fixe, comprenant du fourrage et des concentrés (céréales). Ces pratiques sont à l'origine d'une épidémie d'obésité dans l'espèce équine. Les propriétaires de chevaux et les éleveurs n'ont souvent pas conscience des besoins réels de leur cheval et ne suivent pas son état corporel, pou11ant facilement mesurable avec la note d'état. L'obésité est une pathologie qui se définit par une accumulation excessive de graisses, elle constitue un facteur de risque pour d'autres pathologies comme l'ostéochondrose ou la fourbure. Dans le contexte des origines développementales de la santé et des maladies, l'obésité chez la jument pourrait avoir des effets sur la descendance, et ce, potentiellement par le biais de la lactation. Objectifs: L'objectif de ce travail a été de déterminer les profils en acides gras des laits de juments obèses ou normales au cours de la lactation (de la naissance au sevrage), pour les comparer entre eux et en étudier l'évolution quantitative et qualitative au cours du temps. Parallèlement à l'étude des pro fils en acides gras du lait de 2 groupes de juments anglo-arabes multipares, nous avons également exploré des profils en acides gras plasmatiques des juments et de leur poulain, pour évaluer si la composition lipidique du lait reflète ou non celle du plasma des juments et peut expliquer celle des poulains. Méthodes Des échantillons de plasma et de lait collectés à cinq temps de la lactation (JO=colostru m, J 10, Ml , M3 et M6=sevrage) ont subi une extraction lipidique par des solvants organiques (chloroforme-méthanol), les acides gras extraits ont été méthylés avant d'être analysés par Chromatographie en Phase Gazeuse (CPG). Résultats: Les concentrations du lait en acides gras varient en fonction du temps mais sans différence significative entre les groupes de juments. Un pic de concentration en acides gras a été observé à 10 jours, coïncidant avec les « chaleurs de lait » (premières chaleurs après le poulinage) des juments. Qualitativement, le colostrum des juments obèses est moins riche en acides gras saturés à chaine moyenne, ces différences s'estompent avec J e temps durant la lactation. Bien que peu de différences significatives soient trouvées entre les groupes de juments, les analyses factorielles multiples (AFM) des données de composition du lait et des plasmas permettent de bien séparer les deux groupes de juments et leurs poulains à chaque temps de la lactation, mais avec une significativité décroissante au cours du temps

Periconceptional body condition, feto-placental development and foal metabolism in horses

International audience32 pregnant saddlebred mares were divided in 2 groups from 7 months of gestation. Control mares (n=15) were fed to requirements whereas H-mares (n=17) were fed +15.5% energy and +30.4% proteins. Maternal weight and body condition score (BCS, 1-5 scale), foal growth and fasting glycemia were monitored. Results were analyzed using a linear model.The BCS of H-mares remained ≥3.5 throughout gestation but that of L-mares decreased from 9 months of gestation (foaling BCS: 2.75) despite no difference in weight. Fasting glycemia in H-foals was lower at 1 month (p=0.03) and 3 months (p=0.09, tendency) compared to controls. There was no other difference between groups. Data were analyzed sorting the mares according to BCS at insemination into Fat (F, n=18, BCS: 3 to 4.25) and Normal (N, n=14, BCS: 2 to 3.75) groups. There was no difference in food intake between groups. F-mares kept a high BCS until foaling but the BCS of N-mares decreased from 7 months until foaling (foaling BCS: 2.75). At birth, F-placentas were 12% lighter (p<0.01), F-foals 1.4kg lighter (p<0.01) and 1.04cm smaller (p=0.04) than N-foals. There was no difference growth but F-foals had lower fasting glycemia at 1 month (p=0.03). Mares were also sorted by parity: multiparous (M, n=20) and primiparous (P, n=12). There was no difference in food intake between groups. M-mares had a high BCS (≥3.5) until foaling. P-mares were lighter (p<0.01), their BCS was lower (p<0.01) until 8 months of gestation. Gestation was shorter by 7 days (p=0.01) in P-mares. At birth, P-placentas were 16% lighter, P-foals 8.6kg lighter (p<0.01) and 5.1cm smaller (p<0.01) than M-foals. They remained lighter and smaller until 9 months of age. Fasting glycemia was higher at 1 day (p=0.02) and 3 months (p=0.08, tendency).In conclusion, we demonstrate the importance of periconceptional maternal BCS and parity on feto-placental and foal metabolism, based on a study initially aiming at exploring effects of nutrition during gestatio

Effect of energy supplementation on grass intake, performances and parasitism in lactating mares

National audienc

Barley supplementation at mid-gestation in broodmares does not affect fetal development and is accompanied with minimal placental adaptations

National audienceModifications of maternal environment could alter fetal growth and development through the placenta and thus health in adulthood. Osteochondrosis is an osteo-articular pathology which affects young horses and strongly impacts the equine industry. It has been shown that breeding practices, especially feeding pregnant mares with concentrate in the last part of gestation, could play a role in the development of this disease . To understand the effect of feeding practices during gestation, 24 saddlebred mares were allocated to one of two groups: group B was supplemented twice a day with barley (B) and group F was led only with fodder (F) between the 7th month of gestation and foaling. B mares maintained an optimal body condition score through gestation, with an increase in glycaemia and insulinemia alter each meal and an insulin resistance in the 9th month of gestation. F mares lost condition as assessed by body condition score in the last part of gestation, leading to a moderate undernutrition and a transitional increase in Non Esterified Fatty Acid plasma concentrations. Diets had no effect on feto-placental biometry, nor on placental structure. ln contrast, an increase in microcotyledonary vessel volume was observed in F placentas, indicating placental adaptation, possibly to increase fetomaternal exchanges- There was no overall difference in the expression of genes involved in vascularization, nutrient transfer growth and development between placentas from B and F mares. Nevertheless, as seen by others , sex-specific effects of maternal nutrition were observed in placentas from female foals, with differences in the expression of Endogline, Kinase insert Domain Receptor, lnsulin-like Growth Factor 2 and lnsulin-like Growth Factor 1 Receptor genes. This study demonstrates that breeding practices, i.e., supplementation in concentrate at mid-gestation, do not seem to affect fetal development