| Practice Tip | Peer reviewed |
Cite as: Jacela JY, DeRouchey JM, Tokach MD, et al. Feed additives for swine: Fact sheets – flavors and mold inhibitors, mycotoxin binders, and antioxidants.J Swine Health Prod. 2010;18(1):27–32.
Also available as a PDF.
Under the conditions of modern swine production, pigs need to be fed a balanced diet that meets their daily nutritional requirement for maintenance, growth, and reproduction. However, nutrient intake is largely determined by voluntary feed intake, which is greatly influenced by the chemical senses of olfaction and taste. Thus, it is essential to make sure that diets being offered to pigs are highly palatable to ensure high feed intake. This is especially important during times when pigs have decreased appetite, such as the first few days post weaning. Therefore, it is believed that enhancement of taste or smell through the use of flavors may help to improve the palatability of diets and, consequently, feed intake.
Factors affecting feed intake
A number of factors have been identified that affect feed intake in pigs. In most cases, feed intake is influenced by the interaction between some or all of these factors, which include the thermal environment, social factors (eg, stocking density), animal factors (eg, genotype), and dietary factors (eg, energy density and palatability).1 Palatability of a diet refers to its acceptability features, including taste, smell, and texture, that the pig senses before feed is swallowed.
How can palatability of diets be improved?
Palatability of a diet may be measured by comparing the amount of that diet that a pig consumes relative to the amounts consumed of other diets. Palatability can be improved by using ingredients preferred by pigs or by using feed additives, such as flavors, that make the diet more acceptable and encourage greater feed intake. The number of taste buds in pigs are at least three times that found in humans,2 suggesting that their sense of taste may be more developed and thus more responsive to varying tastes and flavors in their food.
What are flavors?
Flavors are feed additives that attempt to enhance the taste and smell of feed to stimulate feed intake. Taste and smell are the senses associated with feed intake. Because smell is the first sensation detected by the pig, aroma of the diet becomes the initial stimulus that drives the pig to eat.3 Flavors also mask ingredients that are unpleasant to pigs.
In countries where small-scale pig production is still widespread and producers buy commercially available feed products from distributors, flavors are used by feed manufacturers mainly as a marketing tool to attract feed buyers. Farm owners tend to believe that feed products that smell good to them will also be acceptable to their pigs;4 however, this may not be the case, as large differences in sense of taste are known to exist between species.2,5
At what stage of production are flavors applied or used in pig diets?
Flavors and aromas are primarily used at stages when feed intake is expected to be lower, such as in the postweaning period. During and immediately after weaning, the pig is subjected to significant stress brought about by a number of physical, physiological, and behavioral changes. These include separation from the sow, new environment, and dietary transition from sow’s milk to a completely solid food. Identifying and adjusting to the new diet take some time and further contribute to the growth lag experienced by a young pig. Flavors may help improve the performance of pigs during this stage through increased feed consumption by making the feed more attractive and highly palatable.
This same principle applies to the use of flavors and aromas in creep feed and milk replacers. Some products claim to enhance palatability of creep feed by mimicking the taste of sow’s milk. Suckling pigs are stimulated and learn to eat solid food earlier, making the transition to completely solid food during weaning less stressful.
Most sows consume less feed than needed to support the demands during lactation. Thus, flavors may be of some benefit to help increase sow feed intake. However, there is no research data to support this claim.
What flavors are included in commercially available swine-feed additives?
A number of studies5-9 have been conducted using a wide variety of flavors to identify those most preferred by the pig. Most studies reported a preference for a sweet taste. That is why most products added to the feed as flavoring agents include sweeteners such as saccharin and talin. Others include vanilla and milky or fruity flavors or a combination of these.4 Acceptability of these flavors to pigs was identified using preference studies7 wherein pigs were simultaneously offered diets with different tastes. Taste preference was identified in terms of which diet with a particular flavor was consumed the most relative to the total feed intake of the test diets, commonly expressed as a percentage of the total amount of feed consumed.3,10
Does the addition of flavors translate to improvement in performance?
Preference for a certain flavor does not necessarily mean that feeding it will result in improvement in feed intake and performance. While a number of studies6,8,9 have shown that pigs prefer certain flavors when given a choice, using these flavors in performance studies did not necessarily show positive effects when pigs were not given a choice.6,11
Growth-performance experiments12-15 also have shown varying results, with most improvement in feed intake being observed during the first week after weaning.8 In one recent study,16 adding an enhanced flavor to creep feed given 3 days before weaning did not affect litter feed intake, the proportion of piglets consuming creep feed, or preweaning performance. However, exposure to the same enhanced-flavor product was associated with greater postweaning daily gain of pigs fed complex diets, but did not influence performance of pigs fed simple diets.16
Summary
Feeding pigs with a well-balanced diet that is highly palatable is essential for optimal growth performance and production efficiency. While the use of flavors may be a useful tool to improve palatability and feed intake under certain conditions, the effectiveness of these feed additives has not been consistently observed in different experiments. In addition, feed intake is regulated by multiple factors, not just taste. Therefore, careful evaluation of commercially available products and consultation with a nutritionist is recommended before a flavor is added to a swine diet.
References
1. Nyachoti CM, Zijlstra RT, de Lange CFM, Patience JF. Voluntary feed intake in growing-finishing pigs: A review of the main determining factors and potential approaches for accurate predictions. Can J Anim Sci. 2004;84:549–566.
2. Hellekant G, Danilova V. Taste in domestic pig, Sus scrofa. J Anim Physiol Anim Nutr. 1999;82:8–24.
3. Frederick B, van Heugten E. Palatability and flavors in swine nutrition. Raleigh, North Carolina: North Carolina State University; 2003; Publication No. ANS02–821S. Available at: http://www.ncsu.edu/project/swine_extension/publications/factsheets/821s.htm. Accessed 7 October 2009.
4. Thaler RC, Sulabo RC. Traditional and non-traditional feed additives for swine. Technical Report Series: Swine Nutrition and Management. Singapore: American Soybean Association International Marketing Southeast Asia; 2006:23–29.
5. Nofre C, Glaser D, Tinti JM, Wanner M. Gustatory responses of pigs to sixty compounds tasting sweet to humans. J Anim Physiol Anim Nutr (Berl). 2002;86:90–96.
6. Wahlstrom RC, Hauser LA, Libal GW. Effects of low lactose
whey, skim milk and sugar on diet palatability and performance of
early weaned pigs.
J Anim Sci. 1974;38:1267–1271.
*7. Baldwin BA. Quantitative studies on taste preference in pigs. Proc Nutr Soc. 1976;35:69–73.
8. McLaughlin CL, Baile CA, Buckholtz LL, Freeman SK. Preferred flavors and performance of weanling pigs. J Anim Sci. 1983;56:1287–1293.
*9. van Heugten E, Roura E, Gibson M. Milky flavor alone but not in combination with sweeteners improves preference at a dietary change from piglet prestarter to starter feeds [abstract]. J Anim Sci. 2002;80(Suppl1):393. Available at: http://www.asas.org/jas/2002abs/jnabs125.pdf. Acessed 30 October 2009.
10. Solà-Oriol D, Roura E, Torrallardona D. Use of double-choice feeding to quantify feed ingredient preferences in pigs. Livest Sci. 2009;123:129–137.
11. Forbes JM. Growth and fattening. In: Voluntary Food Intake and Diet Selection in Farm Animals. 2nd ed. Cambridge, Massachusetts: CABI; 2007:310-340.
12. Kornegay ET, Tinsley SE, Bryant KL. Evaluation of rearing systems and feed flavors for pigs weaned at two to three weeks of age. J Anim Sci. 1979;48:999–1006.
*13. Schlegel P, Hall R. Effects of diet type and an artificial high intensity sweetener (SUCRAM®) on weaned piglet performances [abstract M122]. J Anim Sci. 2006;84(Suppl1):45–46. Available at: http://adsa.asas.org/meetings/2006/abstracts/39.pdf. Acessed 30 October 2009.
14. Millet S, Aluwe M, De Brabander DL, Van Oeckel MJ. Effect of seven hours intermittent suckling and flavour recognition on piglet performance. Arch Anim Nutr. 2008;62:1–9.
15. Sterk A, Schlegel P, Mul AJ, Ubbink-Blanksma M, Bruininx EMAM. Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs. J Anim Sci. 2008;86:2990-2997. doi:2527/jas.2007-0591.
16. Sulabo RC, Tokach MD, DeRouchey JM, Risley CD, Nelsson JL, Dritz SS, Goodband RD. Influence of organoleptic properties of the feed and complexity on preweaning and nursery performance. Kansas Agric Exp Sta Prog Rep 1001. 2008;1001:31–41. Available at: http://www.ksre.ksu.edu/library/lvstk2/srp1001.pdf. Accessed 2 March 2009.
* Non-refereed references.