Tannins in selected fodder legumes

Many plants have developed defense mechanisms for survival. Fodder legume species or plants used as animal feed, for example, produce chemicals or secondary compounds not directly involved in the process of plant growth but act as deterrents to insect and fungal attack or to being eaten by animals.

One such compound is tannin. As previously reported, species which contain some tannins provide both degradable and undegraded rumen nitrogen (N) and are more effective sources of supplemental N for ruminants. Tannins also have anthelmintic properties or the capacity to reduce parasite loads.

Throughout the country, multipurpose trees and shrubs such as ipil-ipil (Leucaena leucocephala), kakawate (Gliricidia sepium), acacia (Samanea saman), sesbania (Sesbania sesban), rensonii (Desmodium rensonii), and flemingia (Flemingia macrophylla) are used as supplementary feeds to low quality diets for ruminants. They are cheap alternatives to concentrates necessary to improve animal productivity.

As these plants are important in the diets of ruminants (e.g. sheep, goats, cattle and carabao), there is thus a need to determine their tannin contents. This will provide information on their nutritive values as well as anthelmintic properties that can serve as basis in developing tree/shrub–based feeding strategies.

In the project “Rural-based enterprise development through innovative goat production systems (RED),” Dr. Edgar A. Orden, deputy director of the Small Ruminant Center-Central Luzon State University (SRC-CLSU) analyzed the tannin contents of 11 fodder legume species being used at SRC-CLSU. These 11 species are Arachis pintoi, Centrosema pubescens, Desmodium cineria, Desmanthus virgatus, Flemingia macrophylla, Gliricidia sepium, Indigofera anil, Leucaena leucocephala, Samanea saman, Sesbania grandiflora, Sesbania sesban.

Of the 11 species evaluated, only five species contained total condensed tannin (TCT). These are flemingia (4,699 µg/g dry matter), ipil-ipil (2,826 µg/g DM), arachis (1,817 µg/g DM), desmanthus (1,176 µg/g DM), and centrosema (33 µg/g DM).

The total extractable phenol (TEPH) or tannic acid equivalent of the legumes evaluated ranged from 1.71 % (centrosema) to 12.28 % DM (flemingia), while total extractable tannin (TET) ranged from 0.16 % (indigo) to 8.27 % (flemingia).

Among the species, flemingia and ipil-ipil consistently had the highest and second highest TEPH, TET, and TCT values, respectively. More than 65% of the extractable phenolic compounds in flemingia and ipil-ipil were accounted as total extractable tannins. This could be a potential factor to affect N degradation in the rumen and possibly availability in the lower gut as well as a good indicator of the species’ deworming properties.

The RED project is a collaborative undertaking of the International Livestock Research Institute, the Department of Agriculture-Bureau of Agricultural Research, and the Department of Science and Technology’s PCARRD. (Elaine F. Lanting, S&T Media Service)

For more information, contact:

Dr. Edgar A. Orden
Deputy Director
Small Ruminant Center
Central Luzon State University
Muños, Nueva Ecija
Tel. nos.: (044) 456-0688 / 0117;
Fax: (044) 456-0688

or

Dr. Patricio S. Faylon
Executive Director
Philippine Council for Agriculture, Forestry and Natural Resources Research and Development
Los Baños, Laguna 4030
Tel nos.: (049) 536-0014 to 20
Fax: (049) 536-0016/0132
E-mail: pcarrd@pcarrd.dost.gov.ph