Antimicrobial Disposition and Interactions With Gastrointestinal Microflora in Equidae

Horspool, Linda Jean Isabel (1992) Antimicrobial Disposition and Interactions With Gastrointestinal Microflora in Equidae. PhD thesis, University of Glasgow.

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Abstract

Penicillin G was detected in plasma (>0.01 mug/ml) for up to 8 h in horses and 6 h in ponies and donkeys following intravenous administration at a dose rate of 10 mg/kg bwt. The elimination half-life (harmonic mean) of penicillin G was similar in horses, ponies and donkeys (38.95, 27.25 and 31.52 min, respectively). The short elimination half-life was reflected by a high mean CLb of 514.46, 505.36 and 462.86 ml/h.kg, respectively. There was an increase in the mean number of coliforms (108-109/g) isolated from faeces following intravenous administration of penicillin G to ponies and donkeys. There was an increase in the mean number of Clostridium spp. (107/g) isolated from donkey faeces following intravenous administration of penicillin G. There were no marked alterations in the viable number of bacteria isolated from caecal liquor, or in caecal liquor pH following intravenous administration of penicillin G; however there was an increase in caecal liquor lactic acid concentrations to 59.5 mmol/1 in 1/2 ponies only. Penicillin G was absorbed rapidly following administration by nasogastric tube to ponies at a dose rate of 10 mg/kg bwt, and peak concentrations of 0.09-0.19 mug/ml were reached at 0.5 h, but the systemic availability was low (0.12-0.34%). Peak concentrations of penicillin G in caecal liquor were high (4.96- 157.12 mug/ml), and there were increases in the number of viable coliforms (107-1010/ml), streptococci (107-1010/ml) and Clostridium spp. (106-108/ml) isolated from caecal liquor. In addition there was an increase in caecal pH from 6.8-7.2 to 7.3-8.3. There were alterations in SCFA concentrations in caecal liquor following oral administration of penicillin G. Namely, an increase in lactic acid concentrations to 5.1-38.7 mmolA, and a reduction in propionic acid concentrations to 0.0-3.7 mmol/1 and butyric acid concentrations to 0.0-3.5 mmol/1, and a reduction in the proportions of propionic and butyric acids to 0.0% and 0.0- 7.1%, respectively. The increase in lactic acid concentrations in caecal liquor was reflected by a slight increase in lactic acid concentrations in faeces to 6.5 mmol/kg. Incubation of penicillin G in vitro ai 31

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: Q A McKellar
Keywords: Parasitology, Veterinary science
Date of Award: 1992
Depositing User: Enlighten Team
Unique ID: glathesis:1992-75262
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 21:25
Last Modified: 19 Nov 2019 21:25
URI: http://theses.gla.ac.uk/id/eprint/75262

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