|Practice tip||Peer reviewed|
Cite as: Jacela JY, DeRouchey JM, Tokach MD, et al. Feed additives for swine: Fact sheets – prebiotics and probiotics, and phytogenics.
J Swine Health Prod. 2010;18(3):132–136.
Also available as a PDF.
Prebiotics are nondigestible food substances that selectively stimulate the growth of favorable species of bacteria in the gut, thereby benefitting the host.
Probiotics are live cultures of beneficial organisms.
Results of growth performance trials with prebiotics and probiotics have been inconsistent.
More studies are needed to justify their use in pig diets.
There is increasing pressure for livestock producers to minimize the use of antibiotics as growth promoters in food animals. Supplementing beneficial microorganisms in the gastrointestinal tract is one potential alternative. A diverse population of beneficial and potentially harmful microorganisms exists in the gastrointestinal tract of the pig. In a healthy animal, a delicate balance between these two groups of organisms is maintained. However, during times of stress, such as during weaning in the case of piglets, this balance may be affected and can lead to a rapid growth of harmful microorganisms. This may result in poor performance or disease. Thus, prebiotics and probiotics have been the subject of much research over the years as potential replacements for antibiotic growth promoters in pigs.
What are prebiotics?
Prebiotics have been described as nondigestible food substances that selectively stimulate the growth of favorable species of bacteria in the gut, thereby benefitting the host.1 These substances are primarily derived from nondigestible oligosaccharides.2 Because they are not digested and absorbed by the pig, they provide readily available substrates for the normal bacteria to grow.2 Oligofructose, fructooligosaccharide, and inulin are examples that have been used as prebiotics.3-5 However, consistent beneficial effects on pig growth performance are yet to be demonstrated with prebiotics.
What are probiotics?
Probiotics are live cultures of organisms supplemented in pig diets that can beneficially affect the host animal by improving the microbial balance in the gut.6 Organisms commonly used include Lactobacillus acidophilus, Enterococci faecium, Bacillus species, Bifidobacterium bifidum, and the yeast Saccharomyces cerevisiae.7 As feed additives, they are supplemented in diets to improve the balance of bacteria in the gut. To be effective, a probiotic must have the following traits:8
- Stability and ability to survive in feed.
- Ability to replicate after passage through the stomach.
- Ability to block the effects of harmful microorganisms or excrete metabolites that can inhibit growth of harmful bacteria.
The proposed benefits from probiotics are improved digestion, stimulation of gastrointestinal immunity, and increased resistance to infectious diseases of the gut.9 Another possible mechanism by which a probiotic may exert its beneficial effect is through its effect on the permeability of the gut, which may increase nutrient uptake and thus improve growth performance. Unfortunately, research results have failed to consistently demonstrate beneficial effects.9-11
What are synbiotics?
The combination of a prebiotic and probiotic is referred to as a synbiotic.12-13 It has been proposed that synbiotics are strategically beneficial for the pig by improving the survival rate and colonization of the introduced probiotic microorganisms in the gastrointestinal tract. At the same time, the presence of prebiotics provides a readily available substrate for probiotic growth and may promote the metabolism of the beneficial bacteria. However, research trials that show consistent beneficial effects in pigs are limited.14,15
Why the inconsistent results in research on probiotics and prebiotics?
The variability in responses suggests several possibilities. The fact that these feed additives improved pig performance in some studies,11 but not in others,10 indicates the influence of environment and production practices, which may differ from one setting to another. It may also be possible that the number of viable organisms in each dose of probiotic was insufficient to be able to survive and become established in the gastrointestinal tract. Another factor might be that the microorganisms included in the probiotic product were not isolated from pigs but from other animal species.
Prebiotics and probiotics do not provide essential nutrients for normal growth. Potential advantages to using probiotics and prebiotics from a health and growth-promotion standpoint include partial replacement of antibiotic growth promoters. However, studies showing more consistent results are needed to justify prebiotic and probiotic use as additives to pig diets. For all the claimed beneficial effects and studies conducted, a consensus has yet to be reached by the scientific community that prebiotics and probiotics consistently provide benefits in commercial settings. Moreover, their addition in the diet entails additional cost and thus must be evaluated thoroughly.
1. Gibson GR, Roberfroid MB. Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. J Nutr. 1995;125:1401–1412.
2. Zimmermann B, Bauer E, Mosenthin R. Pro- and prebiotics in pig nutrition – potential modulators of gut health? J Anim Feed Sci. 2001;10:47–56.
3. Kaplan H, Hutkins RW. Fermentation of fructooligosaccharides by lactic acid bacteria and bifidobacteria. Appl Environ Microbiol. 2000;66:2682–2684.
4. Loh G, Eberhard M, Brunner RM, Hennig U, Kuhla S, Kleessen B, Metges CC. Inulin alters the intestinal microbiota and short-chain fatty acid concentrations in growing pigs regardless of their basal diet. J Nutr. 2006;136:1198–1202.
5. Smiricky-Tjardes MR, Flickinger EA, Grieshop CM, Bauer LL, Murphy MR, Fahey GC Jr. In vitro fermentation characteristics of selected oligosaccharides by swine fecal microflora. J Anim Sci. 2003;81:2505–2514.
6. Fuller R. Probiotics in man and animals. J Appl Bacteriol. 1989;66:365–378.
*7. Simon O, Vahjen W, Scharek L. Microorganisms as feed additives – probiotics. Proc 9th Int Symp Dig Physiol Pigs. 2003;1:295–318.
8. Collins MD, Gibson GR. Probiotics, prebiotics, and synbiotics: approaches for modulating the microbial ecology of the gut. Am J Clin Nutr. 1999;69:1052S-1057S.
9. Doyle ME. Alternatives to Antibiotic Use for Growth Promotion in Animal Husbandry. A Review of the Scientific Literature. Madison, Wisconsin: Food Research Institute. 2001.
10. Keegan TP, Dritz SS, Nelssen JL, DeRouchey JM, Tokach MD, Goodband RD. Effects of in-feed antimicrobial alternatives and antimicrobials on nursery pig performance and weight variation. J Swine Health Prod. 2005;13:12–18.
11. Miguel JC, Rodriguez-Zas SL, Pettigrew JE. Efficacy of a mannan oligosaccharide (Bio-Mos®) for improving nursery pig performance. J Swine Health Prod. 2004;12:296–307.
12. Schrezenmeir J, de Vrese M. Probiotics, prebiotics, and synbiotics – approaching a definition. Am J Clin Nutr. 2001;73:361S–364S.
13. Roberfroid MB. Prebiotics and synbiotics: concepts and nutritional properties. Br J Nutr. 1998;80:S197–S202.
14. Bomba A, Nemcova R, Gancarcikova S, Herich R, Guba P, Mudronova D. Improvement of the probiotic effect of micro-organisms by their combination with maltodextrins, fructo-oligosaccharides and polyunsaturated fatty acids. Br J Nutr. 2002;88(suppl 1):S95-S99. Available at: http://fri.wisc.edu/briefs/antibiot.pdf. Accessed 28 January 2010.
15. Shim SB, Verstegen MW, Kim IH, Kwon OS, Verdonk JM. Effects of feeding antibiotic-free creep feed supplemented with oligofructose, probiotics or synbiotics to suckling piglets increases the preweaning weight gain and composition of intestinal microbiota. Arch Anim Nutr. 2005;59:419–427.
* Non-referred reference.