Business, science behind phytogenics in pig feeds

The increasing pressure to remove antibiotic growth promotants from poultry diets in the U.S. has renewed interest in a family of additives that started as an ingredient in piglet feeds for a similar purpose.

Modern phytogenic feed additives are no longer the equivalent of folklore medicinal or nutritional herbs and spices, but are a sophisticated class of additives. | Farang, Dreamstime
Modern phytogenic feed additives are no longer the equivalent of folklore medicinal or nutritional herbs and spices, but are a sophisticated class of additives. | Farang, Dreamstime

The increasing pressure to remove antibiotic growth promotants from poultry diets in the U.S. has renewed interest in a family of additives that started as an ingredient in piglet feeds for a similar purpose. The apparent success of this additive in poultry has made pig nutritionists give it a second chance, especially since new developments in the formulation of phytogenic products offer solutions to many problems that troubled earlier products. Today, phytogenics are a mainstream type of additives available worldwide, and thus it merits to understand the business and science behind them.

Earlier products of unpredictable efficacy

Phytogenics started as essential oils, if only because most, if not all, of the active compounds were previously classified as such. This is because they were used in aromas — hence the essential part of their name that stems from “essence." Otherwise, animals have no absolute requirement for such compounds that would classify them as essential nutrients. The early products were ground up powders of spices and herbs that provided these essential oils, whereas, at best, they were simple extracts. The major problem that prevented these products from bypassing the initial animal test that most feed manufacturers and pig producers accorded them was the tremendous unpredictability in the concentration of active compounds. As such, additive manufacturers moved on to purified extracts of known concentration and even to synthetic compounds.

Volatility and lost potential

Nevertheless, even when concentration was regulated and became standardized, problems did not disappear. Moving from crude sources to refined compounds revealed another weak point in the application of this additive in pig feeds: they are extremely volatile, and when in purified forms they tend to escape even further. Considering that essential oils are used in aromas, one can understand why they did not take long to escape feed, especially when such material was exposed to heat and moisture that accelerated the deterioration and evaporation of essential oils. As such, results with pigs were rather disappointing: feeds smelled great, but piglets did not seem to benefit much from it. Of course, this is an oversimplification, or even a dramatization of the issue, but it serves to illustrate one of the fundamental hurdles in the science and business of this additive.

Read more: How the pig industry perceives phytogenic feed additives

Overblown expectations

Lead by claims based on folklore medicine and human nutrition (or rather cuisine), users of earlier and even modern phytogenic additive products are often disappointed by results. In human folklore medicine, many herbs and spices are given curative or prophylactic properties, but their effect is rather weak. Today these are considered supplementary to modern medicinal means (drugs such as antibiotics). Again, from medieval through early modern times, when refrigerators did not exist, certain spices and herbs were used (and some still are in preserved foods) to slow down (or mask) food spoilage. Some essential oils have strong antibacterial, antiviral and antifungal properties, but their effect is weak and not as effective as modern preservatives. Still, they are used in preserved foods, but within the above context, understanding their limitations.

feed conversion rate improvements over control groups

This table show field results over many years using a commercial phytogenic product in finishing pigs. | EW Nutrition

Synergistic effects

From the above, it is evident that one would not be unreasonable to expect a much-improved animal response when phytogenics were used in conjunction with other antimicrobial compounds. Indeed, when this was tested, it became apparent that as in the case of human medicine and nutrition, phytogenics are best used to supplement other such compounds. In the case of pigs, these were found to be organic acids. Certain phytogenic compounds actually help organic acids control pathogenic bacteria, whereas some others might be directly effective against bacteria not sensitive to acidity. In short, phytogenics should be used as part of a comprehensive package and not be compared alone against antibiotics.

Phytogenics should be used as part of a comprehensive package and not be compared alone against antibiotics.

Modern products

Phytogenic additive products today contain compounds that control microorganism in the gut, usually in the form of a cocktail including different active compounds from several plants. Others might even include certain compounds that go beyond gut microflora control to enhance digestive functions or even modulate innate host immunity. There are a great number of such mixes in the market as phytogenics are at the verge of becoming a commodity. This is rather alarming because it is easy to mix four purified compounds with a carrier and launch a new product in the market, following the trend of each additives company becoming a “super-market” selling all kinds of additives. But we are risking going back to the beginning where concentration control and volatility issues made this type of additives almost disappear from most pig formulas. Thus, it is imperative one invests in a product that is standardized and designed with utmost care.

Protected phytogenic additives

If one wants to go a step further in ensuring that most of the active compounds found in a phytogenic cocktail reach their target, then there is no remedy but to use a protected product. This is achieved (usually, but not always) by encapsulating the active compounds in a lipid-based formula that is dissolved when entering the small intestine. If the target is the feed itself (sterilization) or the stomach (preventing pathogens from entering), then such products are not suitable. For the former case, phytogenics are rather weak products as other feed preservatives should be employed first, whereas for the latter case, the only remedy is to use organic acids that act at the level of the stomach. Considering, however, that most antibiotic growth promotants worked at the intestine level simply by reducing microbial load (and thus enabling the animal to derive more nutrients from its feed), then protected phytogenic products should be expected to work in a rather similar manner — or at least lead to similar results.

Modern uses

Although phytogenics started as an additive for piglet feeds, today we see them being used in all classes of swine. Of course, in piglet feeds, they continue to be used as part of a strategy that replaces antibiotics not only to improve feed efficiency, but also to reduce the incidence of diarrhea that continues to plague piglets. In sows, especially lactating ones, phytogenics are used to improve feed palatability and reduce pathogen excretion in the environment of neonatal piglets. Finally, in finishing pigs, phytogenics, mostly protected ones, are used solely to improve feed efficiency as the financial benefit is deemed more than important due to the amount of feed (over 70 percent) consumed in the latter phases of growing.

Is it worth it?

Given the number of available products, it is easy to be dismayed by the claims and benefits that in some cases exceed the traditional expectations. In my opinion, it is worth approaching reputable companies with tradition on product quality in order to test their phytogenic compounds. Before doing so, it is important to have a clear understanding not only of what phytogenics can and cannot do but also what is the main anticipation in using such an additive. Quite often, a qualified nutritionist can quickly detect cases where phytogenics cannot offer much simply by making a few simple questions about feed composition. In other cases, it might be necessary to run a test. In either case, phytogenics are becoming a mainstream additive that is no longer possible to ignore.

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