Determination of nutritive value of leaves of a native grown shrub, Glycyrrhiza glabra L. using in vitro and in situ measurements

Abstract

In this study, the nutritive values of the leaves of Glycyrrhiza glabra L., a native grown shrub, hand harvested from three plots established in the experimental field at prebud, mid and late flower stages were evaluated in terms of the chemical composition, in vitro gas production, and in situ dry matter (DM) and crude protein (CP) degradation. Gas production, DM and CP disappearance were determined at 0, 3, 6, 12, 24, 48, 72 and 96 h and their kinetics were described using the equation y = a + b(1 − e − ct ). Maturity had a significant effect on the chemical composition, gas production, metabolizable energy (ME), DM and CP degradability of the leaves of G. glabra L. Neutral detergent fiber (NDF), acid detergent fiber (ADF) and condensed tannin (CT) contents increased with increasing maturity whereas the crude protein decreased. Gas production, DM, CP disappearance and estimated parameters also decreased with increasing maturity. CP, ADF and CT contents ranged from 16.19 to 26.93%, from 20.74 to 29.07% and from 1.57 to 10.83%, respectively. The potential gas production and ME ranged from 65.34 to 72.12 ml/0.200 g of DM and from 10.14 to 12.12 MJ/kg DM, respectively. The effective DM degradability (EDMD) and effective CP degradability (ECPD) ranged from 58.70 to 70.59% and from 57.32 to 73.72%. Gas production, DM and CP disappearance, and estimated parameters of the leaves of G. glabra L. harvested at prebud stage were significantly higher than those harvested at mid and late flower stages. Gas production, DM and CP disappearance, and estimated parameters were negatively correlated with NDF, ADF and CT, whereas they are positively correlated with CP. G. glabra L. harvested at the proper stage of maturity offers considerable potential as a high quality forage for ruminant during critical period in the semi arid and arid regions.