Effect of dietary sodium diformate on growth performance, nutrient digestibility, gut health and profitability in broilers

Dietary formic acid and its salts act against pathogens, helping to decrease pressure on the immune system and improving nutrient digestibility. The use of the double sodium salt of formic acid, with the same antimicrobial properties as formic acid, but with improved handling properties, has become more prevalent in poultry diets. In a trial conducted at a research farm in Taiwan, sodium diformate (NaDF; 0.3% inclusion rate) was tested in a typical corn-soy diet, against a similar control diet containing no acidifier. 120 day-old broiler chicks (male Arbor Acres) were randomly selected and divided into 2 treatment groups with 3 replicates each. Feed and water were available ad libitum. The effects of NaDF on performance (final weight, FCR, broiler index), protein utilization and villi height were examined after 39 days. Data were analysed using the t-test and a confidence level of 95% was defined for these analyses.

Performance was boosted in the birds fed 0.3% NaDF. Treated birds were significantly heavier (2551 g vs. 2316 g; P<0.05), while the FCR improved only numerically (1.67 vs. 1.71). Protein utilization was also numerically better (63.3% vs. 61.6%), while the villi height in the jejunum and ileum was significantly increased by between 170 and 450 µm.  

This study demonstrates that including NaDF in broiler diets is beneficial to performance, nutrient utilization and gut health and thereby increases the gross profit of broiler operations.

Keywords: broiler, sodium diformate, performance, digestibility

Organic acids have a long history of use in animal nutrition, where they are usually added to stabilize compound feed, but also to enhance animal performance. While most early data on this class of additives were collected from studies in pig production (Cole et al., 1968; covering sows, piglets and fatteners), the available literature indicates a later focus on such additives in poultry production. One of the first reports of improved broiler performance when diets were supplemented with a single organic acid was for formic acid (Vogt et al., 1981).
Improvements in broiler performance or their hygienic production conditions with the aid of a variety of organic acids have been reported by many sources, as reviewed by Desai et al. (2007). An important limitation, however, is that organic acids are rapidly metabolised in the fore-gut (crop to gizzard) of birds, which can reduce their impact on growth performance. A newer salt of formic acid, sodium diformate (NaDF), has been demonstrated to be effective against pathogenic bacteria, including salmonella, throughout gastro-intestinal tract (Lückstädt and Theobald, 2009). Reducing the impact of pathogenic bacteria on the broiler, and improving the gut microflora, leads to a state of eubiosis in treated chickens and suggests that the inclusion of diformate in broiler diets can also improve bird performance. This hypothesis was confirmed statistically with a meta-analysis of data from trials carried out in recent years (Lückstädt, 2013). This study analyzed the average impact reported from all studies on the effect of the additive on the performance parameters weight gain, feed efficiency, mortality and productivity. However, these trials focused on weight gain and feed conversion outputs. This study aimed to investigate the effects of sodium diformate on growth performance parameters as well as nutrient digestibility and gut health in broilers.

The trial was conducted at the research farm in Taiwan. One hundred and twenty day-old male Arbor Acres broilers were randomly allotted into 2 treatment groups, with 3 replications and 20 birds in each pen. The commercially-available corn-soy-based feed in one group contained 0.3% NaDF; this group was compared against a negative control. Feed and water were provided ad libitum. Birds were weighed individually after 14 and 39 days; feed consumption was recorded per pen at the end of the trial. The effects of NaDF on performance (final weight, feed conversion ratio, European Broiler Index EBI), protein utilization and villi height were examined after 39 days.

Data were analysed using the t-test and a confidence level of 95% was defined for these analyses.

The inclusion of 0.3% NaDF in the diets of broilers for 39 days exerted significant effects on performance as well as protein digestibility in the birds.

The effect of the additive was already noticeable after only 14 days. At this stage, the body weight of the broilers receiving NaDF had increased significantly (P<0.05), by almost 21% (Table 1). At the end of the trial, treated birds were still significantly heavier (2551 g vs. 2316 g; P<0.05), while the FCR improved numerically (1.67 vs. 1.71). Furthermore, the mortality rate of birds was substantially reduced by 50%. As a result, the European Broiler Index, which includes the three most important productivity parameters in animal production – weight gain, survival and feed efficiency – improved markedly by almost 15%.

Means with a different superscript differ significantly at P<0.05

*EBI = Daily weight gain (g) x Survival (%) / 10 x FCR

Villus height in the jejunum and ileum of birds at 39 days showed a significant increase in birds fed 0.3% NaDF compared to controls (Table 2).

Means with a different superscript differ significantly at P<0.05

Analysis of the protein utilization of the diets showed a numerical increase from 61.6% to 63.3% in the birds fed diets containing NaDF. This substantial improvement, of almost 3% in total, may be related to the larger intestinal surface area in NaDF fed birds due to the longer villi.

Similar trends (improved performance parameters as well as nutrient utilization) were reported as a result of a holo-analysis of 59 published studies for potassium diformate in pig diets (Rosen, as reported by Lückstädt and Mellor, 2011). In broilers, improved zootechnical performance is thought to arise as a result of improved intestinal microflora, through suppressing pathogenic bacterial species; and improved protein digestion. This was supported by the present study as well as in a previous report under similar conditions (Lückstädt, 2014).

As often seen with other additives, the performance improvements recorded are also influenced in part by the hygienic conditions. The current study was conducted at the research farm of a university. This study shows that even under these rather “clean” conditions, NaDF was able to significantly improve bird performance. Under practical conditions with a higher anticipated “bacterial load”, conditions might weigh even more in favour of the additive effects measured. This has been seen with other trials under commercial conditions. It can therefore be concluded that dietary sodium diformate can play an important role in improving broiler production.