Use of phytogenic products as feed additives for swine and poultry

¹ Department of Food Science and Technology, Division of Animal Food and Nutrition, University of Natural Resources and Applied Life Sciences, Vienna, 1180 Vienna, Austria

^* To whom correspondence should be addressed. E-mail: wilhelm.windisch{at}boku.ac.at.

	Abstract

This article summarizes experimental knowledge on efficacy, possible modes of action, and aspects of application of phytogenic products as feed additives for swine and poultry. Phytogenic feed additives comprise a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. The assumption that phytogenic compounds might improve palatability of feed has not been confirmed yet by choice feeding studies. Although numerous studies have been demonstrating antioxidative and antimicrobial efficacy in vitro, respective experimental in vivo evidence is still quite limited. The same applies to the supposition that phytogenic compounds may specifically enhance activities of digestive enzymes and nutrient absorption. Nevertheless, a limited number of experimental comparisons of phytogenic feed additives with antibiotics and organic acids suggested similar effects on the gut, such as reduced bacterial colony counts, less fermentation products (including ammonia and biogenic amines), less activity of the gut-associated lymphatic system, and a greater pre-cecal nutrient digestion, probably reflecting an overall improved gut equilibrium. In addition, some phytogenic compounds seem to promote intestinal mucus production. Such effects may explain a considerable number of practical studies with swine and poultry reporting improved production performance after providing phytogenic feed additives. In total, available evidence indicates that phytogenic feed additives may add to the set of non-antibiotic growth promoters, such as organic acids and probiotics, for use in livestock. However, a systematic approach on the efficacy and safety of phytogenic compounds used as feed additives for swine and poultry is still missing.

Key Words: Antimicrobial, botanical, essential oils, herbs, phytogenic, swine, poultry