| Garlic, commonly used as a supplement in livestock feed, has demonstrated toxic effects in some species. A disk diffusion method was utilized to determine the minimum inhibitory concentration (MIC) of allyl mercaptan against Streptococcus equi in vitro. Subsequently, freeze-dried garlic was offered to 2 horses for 71 days in gradually increasing doses from 0.05 g/kg BW b.i.d. to maximum voluntary intake (0.25 g/kg BW b.i.d.). Jugular blood sampled weekly was analyzed for hematology, biochemistry and Heinz bodies. The in vitro study concluded that allyl mercaptan does not have appreciable antibiotic activity against S. equi as measured by MICs in excess of 8g/L. In vivo, daily garlic in excess of 0.2 g/kg b.i.d. resulted in reduced red blood cell count, total and corpuscular hemoglobin and haptoglobin. There was an increased incidence of Heinz bodies on erythrocytes, erythrocyte size and total and free bilirubin. Recovery was largely complete within 4 weeks. |
