Protected acids improving pig performance

Optimising gut health is a key to improving animal performance. Animals need support to develop and maintain a healthy micro-flora in their intestinal tract. Butyric, caprylic and capric acids strengthen the intestine and therefore improve animal performance and protect the gut against the effects of pathogens.

There are several possibilities to influence gut health. Feed additives such as probiotics, phytogenics, acids, etc. are one option available to the animal producer. Among these feed additives, one possibility is butyric acid. Butyric acid is produced in the large intestine of monogastric animals or in the rumen of ruminants due to microbial degradation of carbohydrates.


The use of butyric acids has several advantages for producers:
  • It is known that protected butyric Protected acids improving pig Optimising gut health is a key to improving animal performance. Animals need support to develop and maintain a healthy micro-flora in their intestinal tract. Butyric, caprylic and capric acids strengthen the intestine and therefore improve animal performance and protect the gut against the effects of pathogens. By Nataliya Roth, Biomin, Herzogenburg, Austria acid is a good growth promoter as it is an efficient nutrient for the intestinal mucosa increasing the density and length of villi, enlarging the absorptive surface of the intestine (Galfi and Bokori, 1990).
  • Butyric acid is also known as an antibacterial agent against pathogenic micro-organisms including Salmonella, Clostridia, Escherichia coli, Brachyspira etc. and as modulator of the intestinal flora supporting useful micro-organisms such as Lactobacilli (Galfi 1990).
  • Butyric acid improves digestibility by increasing activity of intestinal enzymes (Claus, 2006).
  • Moreover, butyric acids upregulates the expression of tight junction proteins, thereby enhancing the barrier function of the epithelium (Bordin, 2004).
  • Overall, butyric acid fortifies the gut of the animal, which leads to improved performance and increased protection against many pathogens.
Table 1. Effect of butyric acid glycerides on growth performance in pigs.
Control Group
Butyric Acid glycerides
Number of animals
Age at trial beginning, days
Weight at trial beginning, kg
Final average weight at day 134, kg
Daily weight gain, kg
FCR during trial

Table 2. Effect of butyric, caprylic and capric acids on growth performance in piglets under sub-optimal conditions.
Glycerides of butyric, caprylic and capric acids
Initial weight, kg
Final weight, kg
Feed intake (g/animal/day)


There are several products on the market providing salts of butyric acid in protected and unprotected forms. Protection makes the handling of the product easier, due to the unpleasant persistent odour of butyric acid. Another reason for protection is to obtain a stomach by-pass of butyric acid and subsequent release of the active substance in the small intestine. Encapsulation of acids is a wellknown form of protection. Another way to beneficially protect butyric acids is in the form of glycerides – which is the combination of acids and glycerol. The glycerol-acid compound is not influenced by the pH of the stomach; therefore these compounds reach the small intestine where the gradual release of the undissociated acids through the action of lipases takes place. In nature, butyric acid glycerides are found in the milk of cows, sows and other species.

Healthy gut
Healthy intestinal mucosa and efficient nutrient uptake.

Subclinical ileitis
Decreased nutrient resorption due to swelling of intestinal mucosa.

Loss of functionality of gut mucosa due to massive swelling.


The effect of butyric acid glycerides was tested on a farm which had problems with ileitis, caused by Lawsonia intracellularis. Figure 1 shows the difference between a healthy gut and a subclinical or chronic form of ileitis. The alteration of intestinal mucosa due to Lawsonia intracellularis can lead to impaired feed conversion and weight gain, as well as poor group uniformity. The trial was carried out on 70-dayold fattening pigs for 63 days on a commercial farm in Italy with 850 DanBred sows. A total of 1,025 pigs were divided into two groups (see Table 1). Both groups received lincomycin and doxycycline for the first 14 days. One group received 0.2% lincomycin and commercial acidifier at 0.3% inclusion rate, whereas the other group received the dietary supplementation with glycerides of butyric acids at inclusion rate of 0.2%. During the trial, blood and faeces were analysed to detect the presence of Lawsonia intracellularis. The Lawsonia antibodies were detected in the blood of both groups. In faeces, the control and treated groups were negative to Lawsonia except for one positive 60 days after the beginning of the trial. The hematic analysis proved that it was impossible to eradicate Lawsonia from both the antibiotic and the glycerides group but it was possible to maintain animal performance. The increased resistance to the infection by the piglets receiving glycerides of butyric acid can be attributed to:
  • better gut and mucosa development
  • increased capacity of repairing lesions caused by pathogens
  • microflora control

Recently developed is a combination of butyric, caprylic and capric acids in the protected glycerides form.* Glycerides allow all acids to act as antibacterial in the intestine, furthermore caprylic and capric acids show very strong antimicrobial activity in the higher pH value (6-7) of the intestine. In addition, glycerides containing butyric acid and medium chain fatty acids possess nutritional value which is especially important for young animals. Mediumchain fatty acids, which are saturated fatty acids mainly composed of 8-10 carbons (caprylic and capric acids), have unique nutritional characteristics different from those of long-chain fatty acids. Medium-chain triacylglycerides (MCT) are more readily digested and absorbed than long-chain triacylglycerides (LCT), and easily utilised as energy.

The efficacy of this combination was tested in a trial carried out with weaned pigs under the surveillance of Prof Dr H. Sarandan, University of Agricultural Sciences and Veterinary Medicine in Timisoara, Romania.

The experiment was carried out 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 m2 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 growth promoting feed additives and the performance improvement should be better with small piglets than with well developed piglets. The piglets in the experiment were monitored for nine weeks, until the average body weight reached 30 kg.

The first group was fed the basal diet without any growth supporting substances and the second was fed weaner diet with glycerides of butyric, caprylic and capric acids included at 1.5 kg per tonne of feed. The dosage was reduced for grower diet to 0.7 kg per tonne of feed. The piglets in the experimental groups were weighed weekly. The quantity of feed consumed per group was determined weekly. The performance results are shown in Table 2.

As can be seen from the data above, the final weight of piglets in the trial group fed with glycerides of butyric, caprylic and capric acids was notably increased compared with the control group. Daily weight gain increased by 16% in the trial group compared to the negative control. This growth rate was achieved with a remarkably reduced FCR (nearly 17%). The performance results of piglets fed glycerides of butyric, caprylic and capric acids 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.

Small piglets were kept separately therefore they did not have to compete with stronger piglets for feed and had the possibility to grow better. Average Daily Weight Gain (ADWG) of small piglets in glycerides of butyric, caprylic and capric acids group was increased by 20% compared to small piglets in the negative control group, whereas the ADWG of big piglets was improved by 12% in comparison with the big piglets in the negative control group. It has to be taken into account that some of the small piglets in the group were undernourished and had subclinical problems at weaning.

The result shows that the combination of acids was able to improve performance very well in the groups with big and small piglets. Especially small piglets need the support of growth promoters, therefore the results for this group were even better.

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