Effect of glycerides of butyric, caprylic and capric acids on growth performance in weaned pigs


The first weeks after weaning are critical stage for the piglets in terms of nutritional, environmental and physiological stresses leading to malabsorption coupled with reduced weight gain and increased morbidity and mortality rates. In the past the dietary supplementation with antibiotics has been proven the efficient tool to compensate the post-weaning stress. However, the public concerns about the potential development of resistant pathogen strains and general food safety resulted in antibiotics ban and consequently forced nutritionists to search for alternative growth promoters. Particular attention has been paid to the short (SCFA) and medium (MCFA) chain fatty acids, which are widely distributed in nature as a constituent of plants, animal tissues or common metabolites of microbial fermentation (Partanen and Mroz, 1999).

Butyric acid is produced along with other SCFA by microbial fermentation of dietary and endogenous residues in the lower gut of all animal species, however in the small intestine of pigs the formation of butyrate is low or absent (Knudsen et al., 2003; Claus et al., 2007). The free butyric acid is rapidly taken up from the gut lumen and it is the crucial oxidative fuel for the colonocytes (Roediger, 1980). Additionally, butyric acid has also been shown to have several cellular effects, i.e. influencing cell maturation and differentiation (Knudsen et al., 2003). Pig mucosa cells are renewed every 2-7 days. Mucosal integrity is ensured by an appropriate balance between the mitotic activity of stem cells in crypt area and apoptosis in the villi tips (Claus et al., 2007). According to some studies butyric acid stimulates mitosis and inhibits apoptosis of mucosal cells in the pigs' colon, consequentially increases the vill length and crypt depth (Galfi and Bokori, 1990; Mentschel and Claus, 2003; Kotunia et al., 2004). Various studies confirmed bactericidal and stimulant effect of butyric acid on beneficial microflora in pigs (Leeson et al., 2005; Boyen et al., 2008) thus leading to improved animal performance (Galfi and Bokori, 1990; Kotunia et al., 2004).

Different reviews showed that approximately fifty percent of newborn piglets' deaths were reported to occur within the first 3 days, because of energy insufficiency (Wieland et al., 1993a, b). To remedy the energy insufficiency medium chain triglycerides (MCT) can serve as a unique supplemental fuel source for piglets (Odle et al., 1991; Odle, 1997). Medium chain fatty acids (MCFA) which are the constituents of MCT having 6 to 12 carbon atoms are more soluble than long chain fatty acids and can diffuse through the enterocytes wall without the assistance of the carriers (Wieland et al., 1993a, b). MCT can be easily absorbed and oxidized by neonatal pigs improving blood glucose homeostasis (Lepine et al., 1989) and energy status of the animal (Benevenga et al., 1989). Moreover, MCFA have been shown to be bactericidal to numerous gram-negative and gram-positive bacteria (Nakai et al., 2002; Skrivanova et al., 2006).

SCFA and MCFA are rapidly metabolized by the microbiota of the gut and absorbed by the epithelial cells along the gastro-intestinal tract (Van Immerseel et al. 2006, Louis et al., 2007). The supplementation of protected fatty acids enables them to reach the further gastrointestinal tract compartments in pigs, where the colonization by pathogenic bacteria mainly takes places, and consequentially reduce the bacterial counts. Reduced colonization of the distal parts of the intestinal tract may in turn correlate with the reduced fecal shedding of bacteria and moreover, improved animal growth performance.

The aim of the study was to evaluate the effect of glycerides of butyric, caprylic and capric acids on the growth performance in weaned pigs.

Materials and methods

A trial was carried out with weaned pigs on a commercial farm in Austria. The trial was conducted in a period of 14 d post-weaning. Eighty-four crossbred piglets (German Landrace x Pietrain; mixed males and females) were weaned at 28 d and transported to the barn where they were housed into crates on slatted plastic floor. The piglets were divided into 4 groups (21 animals per group) that were homogenous for weight and sex. During the trial piglets received the commercial weaned pigs' diet in a mash form. The diet was formulated according to the GfE (2006) requirements. Two groups received the diet containing no feed additive, whereas the other two received the dietary supplementation with glycerides of butyric, caprylic and capric acids (BIOMIN GmbH, Austria) at inclusion rate of 2.0 kg/ton feed. Feed and water were provided ad libitum. The composition and nutrients of the commercial weaned pigs' diet is shown in Table 1 and 2.

Each pen had its own feeder and nipple drinker. The room was equipped with automatic heating and forced ventilation. The temperature was gradually reduced from 29 to 25°C during the experiment.

Table 1. Composition of the commercial weaned pigs' diet (as fed).
Potato protein
Soy protein concentrate
Corn pressure cooked
Whey powder
Palm kern-coconut fat
Mono calcium phosphate
Calcium formate
Magnesium phosphate
Sodium chloride
Vitamin premix
Trace mineral premix
Sweetener&Flavour additive

Table 2. Nutrient composition of the commercial weaned pigs' diet (per kg as fed).
ME MJ 14.3
Crude protein % 17.0
Crude fibre % 2.7
Ether extract % 6.4
Crude ash % 5.0
Calcium g 6.4
Phosphorus g 5.6
Sodium g 2.6
Magnesium g 1.6
Lysin g 14.0
Methionin g 5.3
Threonin g 8.8
Tryptophan g 2.7
Vit. A I.U. 18000
Vit. D3 I.U. 2000
Vit. E mg 230
Vit. C mg 40
Vit. K3 mg 20.0
Vit. B1 mg 3.0
Vit. B2 mg 8.6
Vit. B6 mg 5.1
Vit. B12 mcg 50
Nicotinic Acid mg 60
Panth acid mg 20
Cholinchloride mg 250
Folic Acid mcg 1000
Biotin mcg 150
Copper mg 160
Zinc mg 120
Iron mg 115
Manganese mg 80
Cobalt mg 2.0
Iodine mg 3.2
Selenium mg 0.4

The pigs were weighed in groups at the beginning and at the end of the trial. Feed consumption was recorded for each group daily and then individual feed intake was calculated. Clinical observations for diarrhea, depression, immobility and inappetence were carried out daily.

Results and discussion

All animals remained in good health throughout the duration of the trial. The dietary supplementation with glycerides of butyric, caprylic and capric acids improved animal growth performance. The final body weight (BW) and average daily weight gain (ADWG) were increased by 4 and 14%, respectively, whereas feed conversion rate (FCR) decreased by 18% in the trial group compared to these in the control group (Table 3). The feed intake (FI) was slightly decreased in the trial group compared to the control.

The improved growth performance in the present study is in a good agreement with the studies conducted with butyrates in weaned pigs (Manzanilla et al., 2008, Kotunia et al., 2008). According to the various literature sources SCFA and MCFA are absorbed and transported directly to portal vein to provide animals with additional energy. Especially butyric acid is considered as a nutrient for the epithelium integrity along the intestinal tract (Scheppach et al., 1996). It is indicated that free butyric acid is absorbed very quickly in upper digestive tract and likely is limited of its use. Therefore in the present study the protected butyric acid form coupled with glycerides was used. Unlike free butyric acid, glycerides of butyric acid result in slow release of butyric acid in gastro-intestinal tract delivering it to the further compartments of intestine. Therefore it might be assumed that the higher ADWG in piglets fed glycerides of butyric, caprylic and capric acids improved absorption of nutrients from lumen gut due to increased length of the intestinal villi and therefore enlarged absorption surface of the gut.

Table 3. Effect of glycerides of butyric, caprylic and capric acids on the growth performance in weaned pigs.
Trial 1
No of animals n = 42 n = 42
Initial BW d 28, kg 7.55 7.54
Final BW d 42, kg 10.73 11.16
ADWG, g 227 258
FI/animal/day, g 419 389
FCR 1.85 1.51
BW = body weight; ADWG = average daily weight gain; FI = feed intake; FCR = feed conversion rate

In the present study FCR was improved in piglets fed with dietary supplementation of glycerides of butyric, caprylic and capric acids. The results reported herein might suggest that MCT provided piglets with fuel energy, therefore less feed was needed per unit weight gain. These results are in a good agreement with those of De Rodas and Maxwell (1990) who obtained a significantly increased feed efficiency during the first week post weaning (weaning at 21 to 28 d) by adding 6 % MCT oils. Finally, Dove (1993), feeding 5 % soyabean oil, MCT or animal fat, obtained the highest growth rate with the MCT source. There are discrepancies between the effects of MCT on pig performance. These discrepancies may be related to the absence or very low levels of endogenous gastric or plant lipases (Decuypere and Dierick, 2003).

Regarding to the various literature sources the SCFA and MCFA act against pathogenic bacteria (Boyen et al., 2008; Van Imerseel et al., 2004, 2006). In the present study the counts of the bacteria in gastrointestinal tract were not measured, however it might be assumed that the number of the pathogenic bacteria was decreased reducing the bacterial challenge.


In the present study the dietary supplementation with glycerides of butyric, caprylic and capric acids resulted in overall improved animal performance in weaned pigs. The enhancement of growth performance in pigs might be attributed to the slow release of the butyric acid in gastrointestinal tract. Due to nourishing butyric acid function the intestine villi are enlarged, enhancing absorption area for nutrients. Moreover, triglycerides of caprylic and capric acids provided weaned pigs with the high quality energy, thus improved feed efficacy.

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