Plant secondary metabolites in animal feeds

Animal feeds contain a wide range toxins arising from anthropogenic and natural sources. In this chapter, the distribution of plant toxins in animal feeds and forages is reviewed. The impacts on farm livestock productivity, and on the safety of the resulting edible animal foods, are also considered. Evidence is provided to demonstrate that feeds contain a variety of toxins, and that there are regional differences in the nature of the compounds. Animal feeds may also contain endogenous toxins arising from specific primary and secondary compounds produced by plants which are used as feeds for animals. Thus, feed toxins include compounds of both plant and microbial origin. These compounds also affect animals, including humans, and the nutritive value of forages. Thus, some compounds within plant and microbial toxins may exert anti-nutritive effects and/or reduce reproductive performance in farm animals. Further, the combined effects may be the result of additive or synergistic interactions between the groups of compounds. Effects of secondary metabolites vary with animal species. Non-ruminants (i.e., pigs, poultry and horses) are usually more susceptible to toxicity than ruminants which have the capacity to denature many potential toxins in the rumen. The nature and action of toxins in plants has been the subject of several reviews1,2,3,4,5 , in which attention was focused on pasture plants of commercial importance. The extent and impact of these interactions in practical livestock feeding remain to be quantified, and will be reviewed here. © 2011 Nova Science Publishers, Inc.