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Figure 1: Concept of optical density in ADDCON XL2.0 – nearer to the crystallisation point

Figure 2: Optical density (OD) of a common formic acid – sodium formate blend (PC) and ADDCON XL2.0

Super concentration near the crystallisation point!


Drinking water acidification by means of Addcon XL 2.0

Dr. Christian Lückstädt, Technical Director FEED, Addcon GmbH


Poor quality drinking water is often overlooked in animal production and can lead to reduced productivity and an overreliance on antibiotics. Therefore, ensuring water which is suitable for consumption is absolutely key (Bowen, 2014). Substandard water is relatively common and can trigger adverse impacts on productivity – not least bacterial imbalances in the gut, leading to an increase in antibiotic use. Producers will often look at feed if any performance challenges arise, although a bird or a pig will consume twice as much water as feed.

Table 1: Drinking water guidelines for animal production - from Böhm (2000)


Pathogen  count (CFU)


0 CFU in 100ml


0 CFU in 100ml

E. coli

0 CFU in 10ml

Total (37ºC)


Total (20ºC)



The potential for organic acids to preserve feed and water quality lies in their ability to protect against microbial and fungal contamination and/or degradation. The free hydrogen proton of a dissociated organic acid lowers pH, thereby creating unfavourable conditions for bacterial pathogens. On the other hand, the undissociated form of organic acids directly penetrates the lipid membrane of Gram-negative bacterial cells. After entering cell cytoplasm at neutral pH, organic acids inhibit the bacteria’s growth by inhibiting oxidative phosphorylation and causing increased energy expenditure (H+-ATPase pump) (Lückstädt and Theobald, 2011).

Using organic acids in drinking water rather than feed has a number of advantages (Wales et al., 2010). The ability to apply acids through water during feed withdrawal periods is especially important during pre-slaughter, when the animals’ susceptibility to infection with bacterial pathogens may be increased (Ramirez et al., 1997; Byrd et al., 1998; Corrier et al., 1999). Organic acids in drinking water may also destroy or reduce any vegetative pathogens in the water. Acidifiers used via water can also be used strategically or throughout rearing, to suppress bacterial infections. Free acidifiers, however, are volatile and rapidly metabolised, and thus their efficacy may disappear already within the pipe system or only reaches the foregut.

Concentration is key


In order to overcome such disadvantages, ADDCON has developed a highly concentrated liquid product - ADDCON XL 2.0, which is produced in Addcon’s diformate reactor. Due to the special production process, it is more effective than free acids and easier in handling as well as safer in application. The product contains formic acid and sodium formate, coming from the diformate reaction process, thus it is close to its crystallisation point. This can be measured via the optical density (Fig. 1), which is 12.7% higher than comparable blends of formic acid and its sodium salt (Fig. 2).




ADDCON XL2.0 advantages are:


-       Its higher stability – the product can reach deeper into the GI-tract of animals, due to the higher OD-value

-       Its composition – highest possible stable quantity of formic acid and its sodium salt, which are well known to improve productivity in animal nutrition

Especially formic acid is able to interfere with the growth of pathogenic gram-negative bacteria and is furthermore the only EU-approved organic acid to be a “hygiene condition enhancer”. By acting against pathogens, the active ingredients of ADDCON XL2.0 help to decrease pressure to the animal’s immune system. Furthermore, securing a low pH in the stomach will improve protein digestibility. It is imperative that the product remains available and active while being supplied. Often, liquid acidifiers will be already partly buffered in the piping systems of farms, due to biofilms or calcium carbonate deposits in the pipes. Some suppliers guarantee, after using their products, a low pH in the drinking water system for 5-6 hours. After that, pH usually starts to rise, due to the volatility of the organic acid and the product becomes inefficient.


ADDCON has tested the pH-impact of ADDCON XL2.0, in order to demonstrate the higher stability of the product, under accelerated conditions over 24 hours! The product was able to keep the pH stable over the whole test period. Furthermore, in liquid feed for pigs its usage improved feed efficiency and gut health (measured via diarrhoea days and faecal score; Table 2).

Table 2: Feed efficiency, intestinal health and veterinary costs for fattening pigs, from 60 kg body weight till slaughter (96 kg) fed with liquid feed with or without 1 L of ADDCON XL2.0 per 1000 L liquid feed




Difference (%)





Diarrhoea days (n)




Faecal score*




Veterinary costs




*Faecal score: 1 – liquid, 2 – medium, 3 - hard

The improved digestion, measured indirectly via the FCR and the faecal score, leading to a state of gut health, led furthermore to lower veterinary costs by 0.35€-cents per pig. It can therefore be clearly stated that the use of ADDCON XL2.0 via the drinking water or liquid feed will not only create hygienic conditions, but also lead to improved performance parameters in poultry as well as in pig.


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