Diformates on Broiler Performance

Gastrointestinal diseases pose a serious threat to commercial poultry production. Infections with pathogenic bacteria and their subsequent translocation to other organs and tissues, cause deterioration of feed conversion, increase mortality and reduce productivity. A number of studies have shown enhanced nutritional and growth parameters in poultry, using organic acids. However, most acids are corrosive, with negative impacts on work safety as well as on the feed intake of birds. In a new study, the effects of diformate, a double salt of formic acid, which overcomes such problems, was investigated in relation to performance parameters in broilers. Each of the four treatment groups, 0.1% diformate, 0.3% diformate, 0.5% diformate and negative control, consisted of 35 one day old Cobb broilers, which were raised till 38 days. Diformate addition was found to enhance individual live weights with increasing dosage. By the end of the experiment, treatment improved broiler weight gain by 6.5% to 10.3%. Diformate also improved feed conversion ratio by 7.6% (dosage: 0.1%), 12.0% (0.3%) and 11.4% (0.5%). These findings lead to the conclusion that addition of diformate considerably improves poultry performance by increasing live weight and reducing feed consumption and thus feed conversion, compared to a negative control. The best results in respect of these parameters were obtained for a dosage of 0.3% diformate.

Both the feed industry and the food production sector still suffer from losses due to the contamination with pathogenic bacteria. Their resultant impacts in animals, include lower weight gains and increased mortality. Banning the use of in-feed antibiotics (AGPs) in livestock, as has happened in the EU, placed more pressure on animal producers and feed millers. It also poses an important challenge to innovative animal nutritionists. Addressing these problems in a suitable manner can help the industry regain the trust of consumers and NGO's, concerned about the safety of food. In this respect organic acids have long been used to counteract gram-negative pathogenic bacteria in animal feed, where the beneficial effects of feeding organic acids to monogastric animals on animal performance and health are well accepted. While the effects in pig feeding are well documented, more and more experiments are now conducted in poultry feeding.

The potential of single organic acids in feed preservation lies in their ability to protect feed from microbial and fungal degradation. Their effects on stomach pH and gut flora have also been known for decades and have been proven in many laboratory and field trials (Eidelsburger et al., 1992; Eidelsburger and Kirchgessner, 1994; Freitag, 2007). Acidifiers act as performance promoters by lowering the pH in the gut (mainly the upper intestinal tract), inhibiting the proliferation of unfavourable microorganisms. Gut acidification also stimulates enzyme activity and thus optimises digestion and the absorption of nutrients and minerals. Un-dissociated forms of organic acids penetrate the lipid membrane of bacterial cells and dissociate into anions and protons. After entering the neutral pH of the cell's cytoplasm, organic acids inhibit bacterial growth by interrupting oxidative phosphorylation and inhibiting adenosine triphosphate-inorganic phosphate interactions.

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. (1990a) found significantly reduced levels of Salmonella spp. in carcass and caecal samples, after including calcium formate in broiler diets. Izat et al. (1990b) went on to show that buffered propionic acid could be used to counteract pathogenic microflora in the intestine of broiler chickens, and resulted in a significant reduction in E. coli and Salmonella spp, also on the carcass.

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, 6 kg / t (0.6%) of this organic acid blend was effective in preventing intestinal colonization 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 new molecule (diformate) has been proven to be effective against pathogenic bacteria along the whole gastro-intestinal tract, like Salmonella (Lückstädt and Theobald, 2009). Furthermore, most acids are corrosive, with negative impacts on work safety as well as on the feed intake of birds. In the aforementioned study, the effects of diformate, a double salt of formic acid, which overcomes such problems, investigated the anti-bacterial effects in the GI-tract of broilers (Table 1).

Table 1: Results of various dosages of diformate on Salmonella inhibition (% positive samples)





Table 2: Results of microbiological investigation of the intestine (CFU/g)

  (Data from Lückstädt and Theobald, 2009)

These results clearly show the beneficial effects of diformate against pathogenic bacteria in broilers. No positive samples of Salmonella were found in meat from broilers fed the additive. Furthermore, there were no positive samples for Salmonella in the GI-tract of diformate-fed groups. Notably lower Enterobacter numbers and distinctly higher Lactobacilli and Bifidobacteria counts were further evidence of the beneficial impact of diformate on the intestinal microbiota (Table 2).

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. This hypothesis formed the impetus for a further broiler trial.

A scientific trial with diformate was conducted at the research farm of the All-Russian Poultry Institute in Moscow, Russia. Each of the four groups, 0.1% diformate, 0.3% diformate and 0.5% diformate, as well as a negative control, consisted of 35 one day old Cobb broilers, which were raised to 38 days on a commercial wheat-corn-soy diet.

Feed intake, growth, as well as mortality of birds were recorded. An economic analysis based on the European Broiler Index (EBI) was used to predict the benefit to the farmer. EBI is widely used to describe the efficiency of  broiler production. It is calcluated as:

 

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

 

Statistical analysis was based on the Emperical Rule and µ±2σ was considered to be a significant result.

Diformate addition was found to enhance individual live weights with increasing dosage, at day 26 as well as at the termination of the trial (day 38). By the end of the experiment, diformate treatment improved broiler weight gain by 6.5% to 10.3% compared to the negative control. Based on the Empirical Rule all diformate treated groups differed statistically from the negative control (µ±3σ). Diformate furthermore improved feed conversion ratio by 7.6% (dosage: 0.1%), 12.0% (0.3%) and 11.4% (0.5%) compared to the negative control group. The results are summarized in Table 3.

Table 3: Dose dependent performance of broiler fed with diformate

These findings lead to the conclusion that addition of diformate considerably improves poultry performance by increasing live weight and reducing feed consumption and thus feed conversion, compared to a negative control. The best results in respect of these parameters, calculated as a European Broiler Index (EBI), were obtained for the dosages of 0.3% and 0.5% diformate. The EBI for 0.3% diformate inclusion improved by more than 31% compared to the negative control group.

The mode of action of the acidifier in poultry is mainly due to its antimicrobial action, unlike in pigs where one of the key activities is the reduction of stomach pH. In the trial discussed above, the final body weight of the broiler chickens fed diets with double-salts was significantly increased, while the FCR was also improved - resulting in an improved European Broiler Index. Additionally, other trials have shown improved health status in chickens, as demonstrated by a significantly improved gut microflora - reflected in lower Enterobacter numbers and high Lactobacilli and Bifidobacteria counts (Lückstädt and Theobald, 2009).

Using acidification in broiler diets is therefore a valuable strategy in the producer's armoury against productivity losses caused by pathogenic bacteria.

The results described above prove irrefutably how a healthy gut with inhibited growth of pathogens and food safety can be achieved by dietary means. A balanced acidifier, such as

diformate increases the performance of broiler chickens and is a sustainable option for maintaining or improving broiler growth and efficiency, without resorting to supplementation with an AGP.

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Freitag M. (2007) Organic acids and salts promote performance and health in animal husbandry, pp. 1-11. In: Acidifiers in Animal Nutrition - A Guide for Feed preservation and Acidification to Promote Animal Performance (Lückstädt, C., ed.). Nottingham University Press, Nottingham.

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Humphrey T.J. and Lanning D.G. (1988) The vertical transmission of salmonellas and formic acid treatment of chicken feed. A possible strategy for control. Epidemiology and Infection 100: 43-49.

Izat, A.L., Adams, M.H., Cabel, M.C., Colberg, M., Reiber, M.A., Skinner, J.T. and Waldroup, P.W. (1990a) Effect of formic acid or calcium formate in feed on performance and microbiological characteristics of broilers. Poultry Science 69: 1876-1882.

Izat, A.L., Tidwell, N.M., Thomas, R.A., Reiber, M.A., Adams, M.H., Colberg, M. and Waldroup, P.W. (1990b) Effects of a buffered propionic acid in diets on the performance of broiler chickens and on the microflora of the intestine and carcass. Poultry Science 69: 818-826.

Lückstädt C. and Theobald P. (2009) Effect of a formic acid-sodium formate premixture on Salmonella, Campylobacter and further gut microbiota in broilers. Proceedings and Abstracts of the 17^th European Symposium on Poultry Nutrition, p. 246.

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