Novel acidifier technology for pig production

The EU ban of in-feed antimicrobials has put pressure to identify safe and effective solutions for good animal health and performance in pig production. In addition to higher probability for gastro-intestinal disorders after weaning, especially in early weaned piglets, there is a greater risk for performance losses and increased prevalence of zoonotic pathogens in fattening pigs. In the same time, the regulations concerning Salmonella and other pathogens of animal origin have become stricter along with the recent EU directives on zoonotic agents (EC 2160/2003) and feed hygiene (EC 183/2005).

Research data from the past 20 years demonstrate that acidifiers can carry out many of the functions of antibiotic growth promoters. While the effect of several organic acids on post-weaning performance has been well documented and reviewed e.g. by Partanen (2001), there is increasing body of evidence that organic acids improve the performance of growing pigs as well. Øverland et al. (2000) reported a significant improvement in daily gain and gain:feed in fattening pigs given potassium diformate, and Partanen et al. (2002) observed similar responses to formic acid and to a blend of formic acid and potassium sorbate. The recent review of 19 experiments with fattening pigs (Partanen 2001) indicate that formic, fumaric and propionic acid and potassium diformate improve gain and feed efficiency. In fact, the recent review of Partanen (2003, unpublished) shows that the magnitude of growth performance responses to organic acids is similar in piglets and growing pigs.

Whilst the initial use of acidifiers has been mainly based on single acids and simple mixes, there has been a trend towards more developed solutions. The main targets of these solutions are safety and convenience of use and higher efficacy per unit acid to save cost and space in feed formulations.

The novel solution of Kemira GrowHow is based on advanced formic acid technology, unique carrier and novel "anti-microbial" coating (figure 1). Combination formic acid with water-free ammoniated formic acid and sodium formate reduces the chemical aggressiveness of formic acid but retains or enhances antimicrobial activity. The porous carrier partially encapsulates the liquid acids and acts as toxin binder, showing high in-vitro aflatoxin binding and significant slow-down of in-vivo aflatoxin absorption in chicken gut. Sorbic acid, a solid organic acid, is used for coating and allows a further regulation for the release of the "core" acids and acts synergistically with them.

Figure 1: schema of a loaded particle of diatomaceous earth within the
new range of solid BOLIFOR® Feed Acids.

Controlling the release of volatile acids with the novel technology results in significant advances in the handling and efficacy of the product. The acids react less with feed constituents but retain their anti-microbial activity, which allows the operator to incorporate this acidifier at different levels of the feed manufacture steps. This is especially of importance if acid products are to be included in premixes (including macro minerals) and concentrates with highly buffering minerals. In fact, only chemically inert but less efficient organic acid salts can typically be used in such premixes. Products based on the novel technology are then compatible with most macro-minerals premixes at a practically feasible inclusion level, and they are non-corrosive and non-irritant on skin.

The main targets of the acidifier use include reduction of harmful microbes in the feed and feedstuffs and positive impact on gastro-intestinal microflora. Strong reactive acids may have a high instantaneous killing efficacy on microbes, however, it is reduced over time when the acids bind with feed constituents. Disappearance of non-protected acids in the stomach or crop results in lower efficacy in the small intestine, the main site of beneficial effects.

Figure 2: In vitro binding of aflatoxin by diatomaceous earth (DE) and by a commercial toxin binder (CTB). Data from Alimetrics Ltd, Finland (2005).

Figure 3: Impact of carrier on the anti-salmonella activity of a formic acid based blend in poultry feed. Data from Abbott Analytical UK, 2003.

The novel piglet acidifier, BOLIFOR® “Quick Start” (FA 2800S) was tested for growth performance and gastro-intestinal microflora in piglets weaned at four weeks of age in a research programme organised by the Danish Institute of Agricultural Science and the Danish Slaughterhouses (report n° 666, available online to www.danskeslagterier.dk under “The National Committee for Pig Production” section and in the “Research Results & Reports” area). The product tested at 0.6 % inclusion resulted in elevated endogenous production of lactic acid and inhibition of yeast in the small intestine sampled two weeks after weaning. It also significantly improved growth performance, resulting in 9 % improvement in the 4-10 week production value of the piglets.

The novel technology appears to provide a safe and efficient solution for piglet feeds and feed premixes to ensure good animal performance with antibiotic-free diets.

Figure 4: Effect of BOLIFOR® “Quick Start” (FA 2800S) on the relative daily gain and production value and on the relative contents of lactic acid and yeast in the gastrointestinal tract, as per percentage of values for control diet (report n° 666, Danish Institute of Agricultural Science and the Danish Slaughterhouses).