Effect of physical treatments on phenolics and tannins in Ficus roxburghii and Quercus leucotrichophora leaves

Inadequate availability of straws and conventional concentrates is one of the major constraints for rearing large and small ruminants. Alternative or unconventional fodder resources play a supplementary role in meeting the demand of livestock owners; but these tree leaves contain some antinutritional factors. Tremal (Ficus roxburghii) and Oak (Quercus leucotrichophora) are among the traditional tree fodder sources available in the North Western Himalayan region. Their use a feed stuff for livestock is limited due to presence of tannis. So, the study was undertaken to assess the effect of different physical treatments on total phenol and tannin fractions of Tremal and Oak leaves. Fresh leaves lopped from Tremal and Oak trees of Kangra district of Himachal Pradesh were subjected to physical treatments like chopping and sun drying after chopping. The phenol and tannin fractions of these leaves were estimated before and after treatment. Total phenols, total tannin and hydrolysable tannin contents of the F. roxburghii and Q. leucotrichophora leaves were reduced significantly (P<0.0001) by both the physical treatments. However, both the treatments increased (P ≤ 0.0001) the condensed tannin content of F. roxburghii leaves, whereas chopping followed by sun drying also increased the non-tannin phenol contents. Both the treatments were effective in reducing tannin contents (both hydrolysable and condensed) of Q. leucotrichophora leaves. It may be concluded that physical treatments, chopping, chopping and sun drying, were though effective in reducing hydrolysable tannins, but were not effective in reducing condensed tannin contents of F. roxburghii leaves; whereas chopping, chopping and sun drying were effective in reducing tannin contents in case of Q. leucotrichophora leaves.