The effect of high versus low polyphenol oxidase red clover silage on nitrogen and amino acid metabolism across the rumen of beef steers

摘要

Polyphenol oxidase (PPO) in red clover has been shown to reduce both proteolysis and lipolysis in silo and the rumen (Van Ranst et al. 2011). However all comparisons in vivo have compared red clover with other forages with typically lower levels of PPO, which brings in other confounding factors as to the cause for the greater protection of dietary N on red clover silage, other than just PPO. This study will compare two red clover silages which when ensiled had contrasting PPO activities against a control of perennial ryegrass silage to ascertain the full role of the enzyme in protecting N across the rumen of beef steers.