Introduction

The advantage of adding organic acids to the feed of pigs or poultry has been proven and well documented in the scientific literature. Many independent trials have shown the potential of these substances very clearly but new trials are also necessary to establish performance results under different production conditions. The efficacy of organic acids in the poultry gastrointestinal tract was tested by Professor N. Senkoylu of the Namik Kemal University in Tekirdag, Turkey. The tested product was from Biomin - Biotronic SE forte. The product contains formic and propionic acids on a special carrier which is able to protect acids and release them sequentially in the intestinal tract. The second trial demonstrates the influence of Biotronic SE forte on the performance of piglets. The trial was carried out under the surveillance of Prof. Dr. H. Sarandan from the University of Agricultural Sciences and Veterinary Medicine in Timisoara, Romania. You will find useful information in the following pages about organic acids and their effect on poultry and pig performance.

The growth period is progressively shortened and feed efficiency has to be continuously improved. Nutrition of the animal is becoming more demanding. Nutritive additives, such as acidifiers, still play an important role in animal production. Using the Biotronic SE forte product as an example, the influence of acidifiers on pigs and poultry performance is shown below.

It is generally well-known that acidifiers improve animal performance. Acids start their work via the feed by reducing microbial load, buffering capacity and the pH level in the feed. The level of reduction depends a lot on the acid used because each acid has its own specific range of efficacy. By incorporating different acids, there is a broader spectrum of activity and the product is considerably more effective. The influence of acidifiers in the upper intestinal tract of animal has been investigated and described extensively in the scientific literature. The pH reducing effect of acidifiers in the stomach supports protein digestion. A change in the upper digestive tract influences the lower digestive tract, and in the case of acidifiers this means a reduction of pathogen loads, improved protein digestion and a slowdown in the emptying of the gut which leads to improved digestibility and lower diarrhoea rates. In addition, acids reduce the buffering capacity of the feed, which also improves nutrient digestibility.

Some studies indicate that the response of animals to organic acids may depend on ingredient and chemical composition of the diet. The greatest acidification benefits have been observed when diets were formulated from cereals and plant proteins (Partanen et al., 1999). Wheat and barley can be more cost-effective feed ingredients compared to maize in broiler diets, especially during the harvest season in various regions of the world. However, wheat and barley contain considerably higher levels of anti-nutritional factors consisting mainly of water-soluble and insoluble non-starch polysaccharides (NSP) compared to maize. NSP fractions in wheat and barley have been found to adversely affect nutrient digestion, absorption and the gut microflora (Bedford, 2000). Thus, supplementation of wheat- and barley-based diets with organic acids might alleviate some of the negative effects of NSP in these cereals (Senkoylu et al., 2007).

Broiler Trial

An independent study to examine the influence of acids on broiler performance using a basal diet with different levels of wheat and barley was carried out at the Department of Animal Sciences in Namik Kemal University in Turkey. Day-old male Ross 308 broilers (n=216) were weighed, sorted and randomised prior to placement in broiler battery cages with mesh floors. The experiment was set up in four dietary treatments with six replicates per treatment. Nine birds were placed per cage. Cages were kept in an environmentally controlled room and feed and water were provided ad libitum. A starter diet was fed to chicks for the first three weeks and a finisher diet for the final two weeks. Chickens were weighed individually on days 1, 21 and 35. The experiment was terminated on day 35. Body weight (BW) gain, feed intake and feed conversion ratio (FCR) values were determined at 21 and 35 days of age. Biotronic SE forte was supplemented at 3 kg per tonne in the standard starter and grower diet containing low levels of wheat and barley and in lower nutrient density (LND) starter and grower diets containing higher levels of wheat and barley. The diet composition is presented in Table 1.

Data presented in Table 2 and Figure 1 indicate that the body weight gain of broiler chicks was significantly (P<0.001) increased by 12 per cent due to Biotronic SE forte supplementation in both groups with standard and low nutrient density. Feed intake was also increased in the group fed standard diet by about 5 per cent. A significant (P<0.001) improvement in FCR was also evident for this group by about 6 per cent in comparison with the negative control. Significant (P<0.001) stimulation effect on feed intake (from 2315 to 2688 g) in the LND group was observed due to Biotronic SE forte supplementation, whereby FCR was not completely in line with the control group. The trial showed that poor performance of the negative control group was improved by Biotronic SE forte supplementation. The reason for poor performance of chickens is not known. The enhancement of performance could be also due to the improvement of feed hygiene. Performance enhancement is higher than the average of Biotronic trials. It shows the potential of the product but can not be expected under better conditions.

The trial showed that Biotronic SE forte stimulates overall broiler performance and confirms other reports showing beneficial effects of acidification in broiler chickens with Biotronic products.

Pig Trial

This trial was carried out on a commercial pig farm in Romania under the surveillance of Professor Horea Sarandan from the University of Agricultural Sciences and Veterinary Medicine in Timisoara.

The experiment was done with on two groups of piglets aged 28 days. Each group consisted of 12 piglets (six big and six small piglets), which were housed in two pens with a surface area of 0.39 square metres per piglet. This grouping was made in order to see if the results of the treatment would be different in the small piglets which were underfed during lactation and were at risk of digestive disorders. The consideration was that especially undernourished piglets need the support of acidifiers and the performance improvement should be better with small piglets than with well developed piglets.

The initial weight of small piglets in Biotronic SE forte group was about 13 per cent lower in comparison with the small group of the negative control. The weakest piglets obtained Biotronic SE forte. The piglets in the experiment were monitored for nine weeks until the average body weight reached 30 kg. There were two diets: from 28 days to 56 days and from 57 to 91 days (Table 3).

The first group was fed the basal diet without any growth supporting substances and the second was fed basal diet with Biotronic SE forte included at 3 kg per tonne of feed. The piglets in the experimental groups were weighed weekly. The quantity of feed consumed per group was determined weekly. Average daily weight gain (ADWG) and FCR in each experimental group were calculated. The performance results are shown in Table 4 and in Figures 2 and 3.

As can be seen from the data above, the final weight of piglets in the trial group fed with Biotronic SE forte was notably increased compared with the control group. Daily weight gain increased by 22 per cent in the trial group compared to the negative control. This growth rate was achieved with a remarkably reduced FCR (nearly 24 per cent). The performance results of piglets fed Biotronic SE forte were considerably improved compared to negative control group. The reason of such a difference is understandable in taking into account the different development of small and big piglets as it is shown in Tables 5 and 6.

Small piglets were kept separately therefore they did not have to compete with stronger piglets for feed and had the possibility to grow better. ADWG of small piglets in Biotronic SE forte group was increased by 42 per cent compared to small piglets in the negative control group, whereas the ADWG of big piglets was improved by six per cent in comparison with the big piglets in the negative control group (Figure 4). It has to be taken into account that some of the small piglets in the group were undernourished and had sub-clinical problems at weaning. Especially such piglets need the support of acidifiers to be able to digest and absorb nutrients properly. The trial demonstrates and confirms the crucial importance of acidifiers in the juvenile animal nutrition and the special importance in the supporting of undernourished piglets with acidifiers.

Conclusion

The interaction between health and nutrition of the animal occurs predominantly in the gastrointestinal tract. Acidifiers positively influence gut health and therefore support nutrient absorption. The supplementation of Biotronic SE forte to basal diets with different levels of wheat and barley show the ability of the product to improve broiler performance significantly. Acidifiers improve feed hygiene, reduce the pH level in the stomach and improve digestion therefore enhance poultry performance. In addition, the use of Biotronic SE forte improves growth performance and feed conversion in piglets, showing the importance of the supplementation of the product especially for small piglets.

References

Chost M., Ao Zhigang (2006) Influence of gut health on nutrition. 67th Minnesota Nutrition Conference.

Eckel, Roth F.X., Kirchgessner, M. and Eidelsburger, U. (1992) Zum Einfluss von Ameisensäure auf Konzentrationen an Ammoniak und Biogene Aminen im Gastrointestinaltrakt. J. Anim. Physiol. A Anim Nutr. 67: 198-205.

Frankel, W.L., Zangh, W., Singh. Mediation of the trophic effects of short-chain fatty acids on the rat jejunum and colon. Gastroenterology, 106: 375-380.

Partanen, K.H., Mroz, Z. (1999) Organic acids for performance enhancement in pig diets. Nutrition Research Review, 12: 117-145.

Sakata, T (1987) Stimulatory effect of short chain fatty acids on epithelial cell proliferation in the rat intestine. Br. J. Nutr. 58: 95-103.

Sarandan, H., (2009) Evaluation of natural growth promoters (acidifiers) in weaned piglets" Trial report.

Senkoylu, N.,Samli H.E., Kanter M., Agma A. (2007) Influence of a combination of formic and propionic acids added to wheat- and barley- based diets on the performance and gut histomorphology of broiler chickens. Acta Veterianaria Hungarica 55(4): 479-490.

August 2009