Effect of diet on gentamicin-induced nephrotoxicosis in horses.

This research study examines the extent of kidney damage (nephrotoxicosis) in horses caused by a drug gentamicin sulfate, when the horses are fed on two different diets—alfalfa hay and whole oats. The study shows that horses fed on oats exhibited more kidney damage than those fed on alfalfa hay when both groups were given gentamicin.

Methodology

• The research consisted of two groups of horses: one group was fed alfalfa hay and the other group ate whole oats.
• Both groups of horses were given intravenous gentamicin sulfate at a dose of 5 mg/kg of body weight every 12 hours for 22 days, beginning seven days after the start of their respective diets.
• The urinary gamma-glutamyl transferase to urinary creatinine ratio (UGGT:UCr) was calculated daily for both groups throughout the trial period, as this ratio is an indicator of kidney function.
• The serum concentration of gentamicin was measured 1 and 12 hours after each drug administration.

Findings

• The study showed that a diet of oats amplified the nephrotoxic effects of gentamicin. The mean UGGT:UCr for horses fed oats was significantly higher (100.0 +/- 19.0) than for those fed alfalfa (47.1 +/- 18.8).
• Further, horses that were fed oats had this higher ratio for a total of 54 days, while the horses fed alfalfa only had a ratio exceeding 100 for 7 days, showing more prolonged kidney damage in the oat-eating horses.
• As a control comparison, horses not given gentamicin but fed on either oats or alfalfa had relatively lower UGGT:UCr, of 17.6 +/- 2.2 and 30.5 +/- 3.0 respectively.
• Also the peak and trough concentrations of gentamicin were notably different in horses fed oats and alfalfa, indicating different degrees of absorption or metabolism of the drug dependent on diet.
• However, the half-lives of gentamicin (estimated from peak and trough concentrations) were not significantly different between the groups, showing that the rates of drug elimination were similar irrespective of the diet.

Conclusion

• Hence, the study concluded that horses fed on a diet of oats demonstrated a greater degree of gentamicin-induced nephrotoxicosis than those fed on a diet of alfalfa.
• This suggests that the type of diet affects the extent of kidney damage caused by gentamicin sulfate, which could have implications for managing the risk of nephrotoxic side-effects associated with this agent in clinical settings.