Effectiveness of inoculation with rumen fluid containing <i>Synergistes jonesii</i> to control DHP toxicity in ruminants in eastern Indonesia

Abstract

The feasibility and efficacy of inoculating with rumen fluid as a method to control hydroxypyridone (DHP) toxicity in ruminants on high leucaena diets in eastern Indonesia were investigated. Rumen fluid collected from 2 buffalo identified as ‘protected’, due to low levels of DHP excretion in urine, was orally administered to animals identified as ‘unprotected’ and concentrations of urinary DHP monitored. Control animals were dosed with water only. Treatments were randomly allocated to 10 recipient animals: 3 goats and 7 cattle. All animals were fed a diet containing fresh-cut 100% leucaena during the 18-day study period. Measurement of urinary DHP via colorimetric analysis commenced 8 days prior to animals being drenched with rumen fluid or water and continued for 10 days afterwards. Urinary DHP levels in animals that received the inoculum did not differ from those in the control group 10 days post-inoculation (mean 425 mg DHP/L; P = 0.50). Unexpectedly, DHP levels in all animals (rumen fluid and water) declined with time, although the difference did not reach statistical significance (P = 0.12), and remained above considered safe threshold levels. These results suggest that transfer of rumen fluid to overcome leucaena toxicity in animals in eastern Indonesia may not be effective despite great care having been taken to ensure the viability of the anaerobic organisms during the inoculation process; this methodology is also not a practical solution to replicate on a commercial scale. The findings suggest that inoculation may not be necessary if animals previously naïve to leucaena are able to adapt to DHP toxicity by other means.