Animal husbandry suffers from losses due to contamination with pathogenic bacteria. Their resultant impacts in animals include lower weight gains and increased mortality.

On the other hand, evidence of the development of antibiotic resistant strains of bacteria that are pathogenic to humans has mounted over recent decades; and the practice of using sub-therapeutic levels of antibiotics as growth promoters in livestock production has been heavily implicated in this resistance.

Worldwide, this connection has led to the erosion of consumer trust in agricultural practices that rely on this valuable medical resource. Increasingly, legislation is limiting their use.

Banning the use of in-feed antibiotics in livestock, as has happened in the EU – and currently in a number of Asian countries, placed more pressure on animal producers and feed millers. In this context, organic acids have long been used to counteract Gram-negative pathogenic bacteria in animal feed; and the beneficial effects of feeding organic acids to monogastric animals on animal performance and health are well accepted.

One of the first reports of improved broiler performance when diets were supplemented with single acids was for formic acid (Vogt et al., 1981). Later, Izat et al. (1990) found significantly reduced levels of Salmonella spp. in carcass and caecal samples, after including calcium formate in broiler diets.

The use of pure formic acid in breeder diets reduced the contamination of tray liners and hatchery waste with S. enteritidis drastically (Humphrey and Lanning, 1988). Hinton and Linton (1988) examined how Salmonella infections could be controlled in broiler chickens, using a mixture of formic and propionic acids. They demonstrated that under experimental conditions, 0.6 percent of this organic acid blend was effective in preventing intestinal colonisation with Salmonella spp. from naturally or artificially contaminated feed.

Improving broiler performance or hygienic conditions with the aid of organic acids has been reported by many sources (Desai et al., 2007), as mentioned above. An important limitation, however, is that organic acids are rapidly metabolised in the fore-gut (crop to gizzard) of birds, which will reduce their impact on growth performance. A more complex molecule (sodium diformate - a double salt of formic acid, traded as Formi NDF, ADDCON) has been proven to be effective against pathogenic bacteria, including Salmonella, along the whole gastro-intestinal tract (Lückstädt and Theobald, 2009).

The reduced impact of pathogenic bacteria on the broiler, as well as the improved gut microflora, leading to a state of eubiosis in treated chickens, suggests that including diformate in broiler diets will also result in improved bird performance. It was therefore interesting to estimate the potential impact of sodium diformate (NDF) in poultry production, through an analysis of the results of such trials. A study (Lückstädt, 2013) analysed the average impact from all studies on the effect of the additive on the performance parameters weight gain, feed efficiency, mortality and productivity, as measured using the European Broiler Index (EBI).

The above-mentioned performance parameters are expressed as the percentage difference from the negative control. The final data-set contained the results of 8 documented, negatively controlled studies, comprising 17 trials with NDF-inclusion, which ranged from 0.1 - 0.6 percent. Those studies were carried out the world-over in China, France, Russia, Taiwan and Thailand under both commercial and institutional conditions and included more than 36,700 broilers from different breeds (Arbor Acres, Cobb, Hubbard) raised to between 35 and 44 days.

The average level of dietary NDF from the data-set in all treated broilers was 0.28 percent. Typical dosage for NDF in broilers ranges from 1-3 kg/t feed, depending on age (dietary protein level) and hygienic status of the farm. NDF inclusion resulted in a numerical increase in feed intake of 1.1 percent (P=0.22). However, although feed intake was not improved significantly by NDF inclusion, the performance of broilers, based on daily gain was significantly increased by 5.2 percent (P<0.001). Furthermore, the FCR was also significantly improved (4.1%; P<0.01). Survival was increased on average by 2.3 percent (P<0.05). Finally, the EBI improved significantly due to the inclusion of NDF by 12.4 percent (P<0.001).

Further such trials tested the use of NDF at two different dosages (0.1% and 0.3% NDF) in a commercial broiler diet, against the same diet containing no acidifier. 384 day-old birds (Cobb 500) were randomly selected and divided into three treatment groups with 96 chicks each. The initial weight of day-old chicks was 46 g.

Feed and water were available ad libitum. The effects of NDF on performance (final weight, feed conversion) and litter quality (water content, bacterial load) were examined after 42 days. Data were recorded at the end of the trial. Statistical analysis was based on the t-test and a confidence level of 95 percent was defined for these analyses.

Data on final weight after 42 days of trial period, the feed conversion ratio and litter quality are displayed in Table 1.

Performance was enhanced in birds fed 0.3 percent NDF. Treated birds tended (P=0.09) to be heavier (2.365 kg vs. 2.264 kg), while the FCR tended (P=0.07) to be improved (1.81 vs. 1.89) as well. It should be noted that the 0.1 percent inclusion of NDF led to a significantly (P<0.01) improved FCR against the control
(1.74 vs. 1.89), whereas the final weight of birds fed with that dosage differed only numerically from the control (2.324 kg vs. 2.264 kg).

Litter quality, based on reduced moisture content, was significantly (P<0.05) improved in birds at both NDF-dosages. In conjunction with the improved litter quality, were significantly reduced (P<0.05) faecal levels of Escherichia coli in both treated groups. If looked at the reduction rate, one could say that the use of dietary sodium diformate reduces the E.coli load in faeces by 96-97 percent (Figure 1).

The described results are in agreement with previously reported data. Lückstädt and Theobald (2011) found dose dependent effects on weight gain in broilers fed over a trial period of 38 days. Likewise, the European Broiler Index was enhanced dose-dependently. Furthermore, an inhibition of E. coli after feeding diets with dietary diformate had been reported by Øverland et al. (2000).

The present study therefore confirms once more that dietary sodium diformate in dosages between 0.1 and 0.3 percent has beneficial impacts on the performance of broilers, as well as on the litter quality, measured as bacterial load and faecal moisture. A balanced acidifier, such as diformate, is a sustainable option for improving broiler health as well as growth and efficiency, without resorting to supplementation with an antibiotic growth promoter.

Table 1: Performance parameters and litter quality in broilers fed with or without sodium diformate (Formi NDF)


0.1% NDF

P-levels vs. Control

0.3% NDF

P-level vs. Control

Final weight(kg)












Faecal moisture (%)






by Christian Luckstadt and Stevan Petrovic, ADDCON GmbH, Bitterfeld, Germany

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