Equilíbrio ácido-base e hidroeletrolítico em eqüinos com cólica Acid-base and hidroelectrolytic balance in colic horses

Foram utilizados setenta eqüinos distribuídos em três grupos experimentais, G1 (vinte eqüinos hígidos), G2 (vinte e cinco eqüinos com cólica, os quais passaram por tratamento clínico ou cirúrgico e sobreviveram) e G3 (vinte e cinco eqüinos com cólica, os quais passaram por tratamento clínico ou cirúrgico e foram a óbito ou foram sacrificados). Amostras de sangue foram obtidas em dez diferentes momentos, mediante punção da jugular, para estudo do equilíbrio ácido-base e hidroeletrolítico. Os eqüinos com cólica apresentaram diminuição (P<0,05) nos valores do pH(v), principalmente os animais do G3, a qual, associada com a diminuição da pCO2(v), cBase(v) e cHCO-3(vP), confirmou a acidose metabólica, que teve como origem a produção aumentada de lactato durante a glicólise anaeróbica decorrente da hipovolemia. Adicionalmente apresentaram hiponatremia, hipocalemia e hipercloremia. A presença e a magnitude dos desequilíbrios contribuíram substancialmente com o prognóstico dos animais com cólica.<br>Seventy horses were distributed into three experimental groups ad follows: G1, twenty healthy animals; G2, twenty-five colic horses that survived after clinical or surgical treatment; and G3, twenty-five colic horses that were sacrificed or died after clinical or surgical treatment. Blood samples were taken from the jugular vein to assess acid-base balance and water-electrolyte balance. Colic horses had lower pH(v) (P<0.05), mainly G3 animals. Acidosis was confirmed by the lower pH(v) associated with decreased pCO2(v), cBase(v) and cHCO-3(vP), which was probably due to an increased production of lactate during anaerobic glycolysis as a result from hypovolemia. Furthermore, hyponatremia, hypokalemia and hyperchloremia were detected. The presence and the extent of the imbalances contributed substantially to the prognosis of colic horses

Changes in equine hindgut bacterial populations during oligofructose-induced laminitis

In the horse, carbohydrate overload is thought to play an integral role in the onset of laminitis by drastically altering the profile of bacterial populations in the hindgut. The objectives of this study were to develop and validate microbial ecology methods to monitor changes in bacterial populations throughout the course of experimentally induced laminitis and to identify the predominant oligofructose-utilizing organisms. Laminitis was induced in five horses by administration of oligofructose. Faecal specimens were collected at 8 h intervals from 72 h before to 72 h after the administration of oligofructose. Hindgut microbiota able to utilize oligofructose were enumerated throughout the course of the experiment using habitat-simulating medium. Isolates were collected and representatives identified by 16S rRNA gene sequencing. The majority of these isolates collected belonged to the genus Streptococcus, 91% of which were identified as being most closely related to Streptococcus infantarius ssp. coli. Furthermore, S. infantarius ssp. coli was the predominant oligofructose-utilizing organism isolated before the onset of lameness. Fluorescence in situ hybridization probes developed to specifically target the isolated Streptococcus spp. demonstrated marked population increases between 8 and 16 h post oligofructose administration. This was followed by a rapid population decline which corresponded with a sharp decline in faecal pH and subsequently lameness at 24–32 h post oligofructose administration. This research suggests that streptococci within the Streptococcus bovis/equinus complex may be involved in the series of events which precede the onset of laminitis in the horse.G. J. Milinovich, D. J. Trott, P. C. Burrell, A. W. van Eps, M. B. Thoefner, L. L. Blackall, R. A. M. Al Jassim, J. M. Morton and C. C. Pollit