Anti-nutritional Factors in Tropical Forage Legumes

Research Project

Project ID: R6421

Title	Anti-nutritional factors in tropical forage legumes
Species	Goat, Sheep
Commodity	Milk, Meat, Draught power
Livestock Keeper Group	Crop Livestock Farmers
Production System	Forest Agriculture Interface
Country or Region	Colombia
Research Theme	Nutrition, Research Process
Research Approach	Laboratory based
Funding Agency	DFID Livestock Production Programme
Overview	This project develops a framework for interpreting chemical analysis of feeds and categorising them 'good' or 'bad'. The gas production technique is developed/ disseminated.

Summary

1. The presence of condensed tannins has an overall negative relationship with in vitro degradability at high concentrations but does not necessarily result in a negative impact on animal productivity and can improve it at low concentrations.

2. The nutritional impact of condensed tannins should not be based solely on their concentration in plant tissue. Tannin structure (hydroxylation level and molecular weight) also needs to be considered, as these are equally important.

3. The effects of tannins on rumen enzyme activity is a function of the characteristics of both protein and condensed tannin amount and structure and may also be related to the living or dead state of the plant tissue on ingestion (i.e. grazed and fresh versus conserved and dead plant biomass).

Primary Relevance	Low - High
Feeding and Nutrition
Animal Health
Commodities and Markets
Other Husbandry
Policy Relevance

Documents

	Anti-Nutritional Factors in Tropical Legumes
	Condensed tannins in tropical forage legumes: their characterisation and study of their nutritional impact from the standpoint of structure-activity relationships (PhD Thesis)

4. The structure of condensed tannins varied when Desmodium ovalifolium was grown under different environments, even for the same cultivar/variety.

5. In vitro degradability is a function of the entire chemical composition of the plant and it is therefore important not to make assumptions where individual factors have been studied in isolation.

6. In vitro experiments should therefore be used as probes for detailed examination of specific aspects of a scientific problem and in making predictions to test in vivo.

7. Binding of tannins to cell wall carbohydrates may be as significant in relation to reducing cell wall digestibility as the effects of tannins are on reducing the rate of protein degradation.

Related Projects

R5180	Assessment of nutritive value of tropical feeds and forages and identification of anti-nutritive factors
R5189	The effects of polyphenolics on ruminant gut metabolism
R5483	Investigation of the mode of action in the rumen of some anti-nutritive factors in tropical legumes
R6340	An evaluation of the gas techniques for identifying digestive interaction between high and low quality forages
R6954	Do dietary tannins (polyphenolics) affect the susceptibility of ruminants to parasitic infection
R7351	Increasing the productivity in smallholder owned goats on acacia thornveld
R7424	Can feeding locally-available plant material rich in tannins reduce parasitic burden in ruminants and hence improve their productivity?