Acute ruminal acidosis (ARA) is the result of increased intake of highly fermentable carbohydrates, which frequently occurs in dairy cattle and is associated with aseptic polysynovitis. To characterise the metabolic changes in the joints of animals with ARA, we performed an untargeted gas chromatography–mass spectrometry (GC-MS)-based metabolomic analysis of synovial fluid. Seven heifers were challenged with an intraruminal oligofructose overload (13 g/kg of body weight [BW]) dissolved in water. Synovial fluid samples were collected at 0, 9 and 24 h post-overload. Metabolome analysis revealed the presence of 67 metabolites. At 9 h post-overload, glyceric acid, cellobiose, fructose and lactic acid were all increased, whereas at 24 h, sorbitol, lactic acid and fructose levels were all increased >10-fold. At 24 h, citric acid and threonine levels were significantly reduced. We detected increased L- and D-lactate, and the presence of interleukin-6 (IL-6) in synovial fluid. Furthermore, using bovine fibroblast-like synoviocytes, we observed that D-lactate induces IL-6 synthesis. Our results suggest that ARA produces severe metabolomic changes in synovial fluid, including disturbances in starch and sucrose metabolism, and increased lactate levels. These changes were observed prior to the appearance of synovitis, suggesting a potential role in the onset of polysynovitis.
, NIMIA MANQUIÁN 4 y RÁUL CRISTI 5 RESUMEN -El estudio propone un modelo simple de persistencia de herbicidas en el suelo basado en una serie de modificaciones al modelo desarrollado por Walker & Barnes. El modelo que se propone simula la degradación diaria de un herbicida en el suelo, a través del funcionamiento de tres submodelos: a) submodelo que estima la temperatura del suelo, b) submodelo del cálculo del contenido de humedad del suelo y c) submodelo que calcula la degradación del producto. Se entrega una descripción teórica de las modificaciones introducidas al modelo y un detalle del programa computacional en lenguaje BASIC. Se hizo una validación independiente de cada uno de los submodelos modificados y se concluye que todos ellos mejoran su eficiencia de predicción respecto al modelo original. La validación del submodelo de degradación se realizó utilizando información obtenida en campo en dos suelos diferentes de los herbicidas metsulfuron-metil y triasulfuron. Finalmente se concluye que el modelo propuesto sería eficiente en la simulación de la persistencia de estas sulfonilureas en el suelo, utilizando una cinética de primer grado para metsulfuron-metil y una de segundo grado para triasulfuron.Términos para índice: efectos residuales, degradación, humedad, temperatura, simulación.
SIMPLE MATHEMATICAL MODEL PROPOSITION OF HERBICIDE PERSISTENCE IN THE SOILABSTRACT -The present study proposes a simple model of persistence of herbicides in soil based on a series of modifications to the model developed by Walker & Barnes. The model proposed simulates the daily degradation of a herbicide in soil, through three submodels: a) soil temperature submodel, b) soil moisture content submodel and, c) degradation of the product submodel. A theoretical description of the modifications introduced to the model and a detail of the software program in language BASIC are given. An independent validation of each one of the modified submodels was done and it concludes that all of them improve the efficiency of prediction of the original model. The validation of the degradation submodel was made using field obtained information in two different soils from the herbicides metsulfuron-metil and triasulfuron. Finally it is possible to conclude that the proposed model would be efficient in the simulation of the persistence of these sulfonylureas in the soil, using a kinetic first degree model for metsulfuron-mehtyl and one of second degree for triasulfuron.
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