Twelve years usage of a natural growth promoter – the Asian experience

With costs of pig production under increasing pressure, the nutrition of young pigs is of increasing interest, as this period is critical to the subsequent performance of the animals through to market. Optimising growth rate and feed efficiency at this time are therefore key requirements for success in today’s animal production systems. While antibiotics are available to assist in improving growth during this phase, there are a range of concerns from world-wide pig producers about their use, including bacterial resistance, palatability and the accuracy of antibiotic dosage if feed intake is compromised. Currently, the use of antibiotic growth promoters comes under increasing pressure from consumers and legal authorities also in Asia. As a result, various feed additives have been studied as alternatives. Organic acids, particularly salts of organic acids, have been reported by many experts to enhance growth performance in the absence of antibiotic growth promoters (AGPs) in pigs, as well as poultry and aquaculture.

A market report from Global Feed Analysts (2010) reported that the global market for feed acidifiers is projected to reach US$1.4 billion by 2015, driven by an increasing demand in developing economies, stable demand for meat and meat products from developed economies and, of course, a swelling world population.

The potential application of organic acids to livestock nutrition and forage preservation has been known for decades and is documented by many scientific studies. Their mode of action has been described extensively in the literature. However, most of the available acids to the industry have an authorization as feed preservatives only. One of them, formic acid, is often described as being the strongest organic acid against pathogen gram negative bacteria; however certain disadvantages, like its unfavourable pungent smell and corrosiveness limit its use in feed production.

The potassium salt of formic acid, potassium diformate (KDF), on the other hand, also has a strong anti-microbial effect, but additionally is proven safe for humans and has no adverse smell. In contrary to formic acid, potassium diformate is a solid product (composition: 35.4% formic acid, 34.6% formate and 30% potassium), which is non-corrosive. Because of its unique chemical structure, KDF combines the chemical properties of an acid and a salt. KDF (FORMI, patented by ADDCON) is the first EU registered zoo-technical additive for sows, piglets and fatteners which improves growth and health performance in all parts of the pig production chain the natural way.

In order to fulfil the EU-registration requirements, KDF passed standards in several trials with weaners, fatteners and sows - the inclusion of KDF in the feed of weaner piglets for instance has been shown in many experiments to have a substantial positive effect on animal performance (Roth et al. 1996; Kirchgessner et al. 1997; Partanen 2001; Diebold and Eidelsburger 2006). The benefit on production performance from supplementing pig diets with KDF seems to originate to a certain extent from enhanced body protein retention (Roth et al. 1998), thus supporting improvements in feed conversion.

The first Asian-trials appeared in 2004, so the additive has been used as a natural growth promoter in Asia since that time. The following trials from Asia prove the aforementioned beneficial effects on growth performance. 

A trial in the tropics (Kasetsart University, Thailand) backed the aforementioned data and thus showed that the additive is working under humid and hot climates as well.  Eighty growing pigs (Duroc x Large White x Landrace crossbreeds) were fed from week 10 till week 17 a typical corn-soy commercial diet with wheat bran as binder, either without or with KDF (0.6%). The initial weight of tested pigs was around 21 kg, while the trial lasted till >50 kg of body weight. The actual data are displayed in Table 1.

A further trial (Lückstädt et al., 2012) under tropical conditions observed the performance enhancing impact of KDF in Vietnam at lower dosages, compared to AGP’s. Eighty 28-day old weaned piglets of equal weight (initial weight 10.1 kg), gender and breed, were allocated to 4 equal groups with 20 piglets each. Piglets were kept at an experimental farm in Southern Vietnam for 28 days, receiving a commercial diet of 19% crude protein with 2975 kcal kg^-1 ME. Diet 1 served as negative control, while diets 2 to 4 contained either 0.4% KDF, 300 ppm Bactrim or 120 ppm Colistin. Feed and water were available ad libitum. At the end of the trial, final weight, daily weight gain, feed conversion and the diarrhoea rate of piglets were obtained and analysed using ANOVA (P<0.05).The data reveal a numerical increase of ADG in the KDF fed group by 4.4%, while the fed conversion ratio was improved by 4.4% as well, thus suggesting improved economics during the period potassium diformate was used.

The final weight of piglets fed 0.4% KDF was significantly increased compared to the control whereas the inclusion of Bactrim or Colistin led only to intermediate results between the control and KDF. Furthermore, a numerical improvement of the feed conversion ratio by 16% was monitored – due to the design of the trial no statistics could be carried out. Finally, the overall days of diarrhoea per group were significantly reduced in the KDF-treatment from 49 d (control) to only 22 d. Similarly, a significant diarrhoea reduction was obtained in the Colistin-group, however, not as pronounced as the KDF-fed group (Table 2).

^*Means with different superscripts in rows are significantly different between treatments (P<0.05)

 

A more recent trial (Lückstädt, 2014) on the same topic was carried out with smaller piglets at the same research facility in Vietnam. Seventy eight 28-day old weaned piglets with an initial weight ranging from 8.0 to 8.3 kg, of the same sex and breed, were allocated to 3 equal groups with 26 piglets each. Piglets were kept at the experimental farm for 28 days, receiving a commercial diet from 28 to 50 days of age with 19% crude protein (CP) and 3100 kcal/kg metabolisable energy (ME), while from day 50 onwards till the end of the trial (56 days of age), a diet containing 20.8% CP (3000 ME kcal/kg) was fed. Diet 1 contained no additive and served as negative control, while diets 2 and 3 contained 0.4% and 0.5% KDF respectively. Feed and water were available ad libitum. At the end of the trial, final weight, daily weight gain, feed conversion and the diarrhoea rate of piglets, as well as pH-data from the gastro-intestinal tract were obtained and analysed statistically using ANOVA.

The final weight of the piglets fed 0.4% and 0.5% KDF was increased dose-dependently, compared to the control (P<0.05). The lowest KDF inclusion improved the final weight by more than 11%, compared to the control. Furthermore, a numerical improvement of the feed conversion ratio of at least 15% was found. Finally, the overall days of diarrhoea per group were significantly reduced with the KDF treatments from 40 days (control) to only 25 and 21 days, respectively (Table 3).

The findings of the two Vietnamese studies support the use of dietary KDF as an effective and sustainable growth-promoter in post-weaned piglets. Current findings suggest that KDF can be used to enhance growth and reduce post-weaning diarrhoea.

The use of potassium diformate as non antibiotic growth promoter has been demonstrated widely to enhance the production performance of growing pigs (Roth et al. 1996; Kirchgessner et al. 1997; Partanen 2001; Eidelsburger et al. 2005; Diebold and Eidelsburger 2006). The mode of action of potassium diformate and other organic acid products based on formic acid has been intensively investigated and documented in the scientific literature (Partanen and Mroz 1999; Eidelsburger 2001; Diebold and Eidelsburger 2006).  It is well-known and accepted in the scientific literature, that acidifier have positive effects on reduced buffer capacity in the feed, accelerated and improved decrease of pH value in stomach contents with the subsequent better development of digestive enzymes (Roth et al. 1996; Kirchgessner et al. 1997; Partanen and Mroz 1999; Eidelsburger 2001; Partanen 2001). In combination with the well documented positive effects of potassium diformate on digestibility of nutrients (e.g. protein), reducing E. coli, salmonella and other pathogenic bacteria and therefore optimizing the digestion process in the small intestine and hindgut of piglets (Diebold and Eidelsburger 2006), there might be an explanation for such more pronounced effects of potassium diformate on feed conversion of piglets and growing pigs. Finally, in a holistic analysis (collection of all published data on the use of acidifier in swine - 658 negatively controlled trials with 158 different acid products on a total of 37,924 pigs) KDF outperforms all other acidifiers available at the market by its effects on growth and feed efficiency. Potassium diformate (KDF, FORMI), based on 59 trial results, has significant beneficial effects on feed intake (+3.52%), live weight gain (+8.67%) and feed conversion ratio (-4.20%) of pigs, compared to negative control. Importantly, the Holo-Analysis demonstrates irrefutably that using acids, and especially FORMI, in pig diets does improve the productivity parameters of greatest importance to economic success of the pork industry.