Potassium diformate (KDF) is a specifically conjugated acid double-salt (HCOOH HCOOK), patented by ADDCON and traded as FORMI on the European and world-markets. Potassium diformate has been approved in the European Union as a non-antibiotic growth promoter for use in diets for piglets, growing-finishing pigs and in sows. It was also registered as the first replacement for in-feed antibiotics world-wide. This article series describes the effects of KDF fed to sows on nutrient digestibility, microbiota in sow faeces and sow body condition during gestation, farrowing and lactation, including sow milk composition and the subsequent impact on growth performance of piglets. The first article covers the impact on the sow itself.
Agricultural production and the feed industry world-wide continue to suffer from losses caused by contamination with pathogenic bacteria and the associated consequences in livestock, such as reduced weight gain and increased mortality (Lückstädt and Kühlmann, 2014). Many scientists believe that “…Dietary acidifiers can actually become the most common and efficacious alternative solution to antibiotics, in order to improve health status and performance of pigs” (Papatsiros and Billinis, 2012). Currently, potassium diformate (KDF, traded as FORMI®, ADDCON) has and is been used in piglets, fattening pigs and sows - thereby covering the whole pig production chain. In general, the impact of the product can be described as following:
In the digestive tract of the animal the product has a double effect; it acts as an acidifier and as an antibacterial agent. The ability of the product to lower the pH in the animal's stomach, allowing it also the potential to improve the digestion, absorption, and utilization of ingested dietary nutrients. The antibacterial effect of the product is based on the stability of the molecule and its strong antimicrobial effect against harmful bacteria in the lower parts of digestive tract (mainly Gram-negative bacteria), while having a positive impact on beneficial Gram-positive bacteria, like Lactobacillus and Bifidobacterium (Øverland et al., 2000; Canibe et al., 2001; Knarreborg et al., 2002).
Numerous trials have been carried out world-wide and a Holo-analysis of all published trials confirms that FORMI improves on average the feed intake in swine by 3.5%, weight gain by 8.7% and feed efficiency by 4.2% (Lückstädt and Mellor, 2010). Most of these data stem from the use of KDF in weaned piglets and growing-finishing pigs. However, more recently, data on the use of KDF in sows are also available. Øverland et al. (2008) described the effect of KDF in the diet of reproducing sows, especially on performance of sows and their litters. These authors concluded that adding KDF to diets for sows had a positive effect on the sows’ backfat thickness in gestation and on growth performance of piglets. A further study (Lückstädt, 2011) found that the inclusion of KDF in sow diets from pre-farrowing till weaning can improve feed intake and condition in sows.
In trials conducted in sow with dietary KDF, several beneficial impacts were noticed during the trial period. KDF was used in most of the trials from one week before farrowing till the end of weaning, so covering a period of roughly 4 weeks.
In all of the trials, increased feed intake in sows was noticed. During the period from the first seven days of using KDF before farrowing, the change in feed intake is not significant, however, after farrowing and during lactation, we see a larger feed intake in sows, reported between 150-300 g/day (Landkildehus, KFK, Denmark, 2001; Figure 1) and 800 g/day (Lückstädt and Greiffenstein, 2016; Table 1). According to many observations, if maximum feed intake is realised at an early stage of lactation, then this results in maximum feed intake during the total lactation period, increased milk production and reduced loss of weight of the sow. Furthermore, for each additional kilogram of daily feed intake during lactation, +0.1 piglets are born in the following cycle (Koketsu et al.).
Figure 1: Daily feed intake of sows fed with or without FORMI
(Landkildehus, KFK, Denmark, 2001)
Table 1: Effects of 0.5% dietary potassium diformate (FORMI) in sows fed from one week before farrowing till weaning (modified after Lückstädt and Greiffenstein, 2016)
Control of weight and backfat losses during lactation are key to optimizing reproduction. When backfat losses between farrowing and lactation of sows were measured under the impact of different seasons in Spain (Table 2), it was noticed that sows with dietary KDF had a significantly lower backfat loss compared to sows of the negative control group.
Table 2: Backfat measurements of sows fed with or without FORMI (in mm), (internal report - University of Barcelona, 2006)
x, y mean values within one column and within one experimental period with different superscripts are significantly different (P < 0.05)
It has furthermore been found that inclusion of KDF in the diets of sows tended to increase total digestibility of fat and increased the content of estimated energy in the lactation diets (Øverland et al., 2008). As can be seen in Table 3, the sows that had KDF in their diet, consumed more energy after farrowing than sows fed without KDF. Sows fed with KDF required significantly less energy to compensate the body weight loss during lactation.
Table 3: Effect of FORMI on sows under tropical conditions (after Lückstädt, 2011)
*based on 3.224 Mcal ME/kg lactation feed; **based on 5.971 Mcal ME/kg feed energy to rebuild mobilised body mass (after Weiland, 2012)
Supplementing sow lactation-diets with KDF lead to a higher feed intake. This results in reduced backfat loss of sows and an increased digestibility of fat and content of estimated energy of diets during lactation. Post-lactation, these sows are in a better metabolic condition to return to oestrus more quickly. Since it is desirable to reduce the number of days between farrowing and conception to produce more litters per sow per year, it is therefore highly recommended to regularly use potassium diformate - traded as FORMI (ADDCON) in the lactation diet of sows - to improve the overall condition of the sow.