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Review Article


Butyric Acid as an Antibiotic Substitute for Broiler Chicken–A Review


Kumarasamy Deepa1*, M.R. Purushothaman2, Purushothaman Vasanthakumar3, Karuppsamy Sivakumar4

1Department of Animal Nutrition, Veterinary College and Research Institute, Namakkal – 637 002; 2Department of Animal Nutrition, Veterinary College and Research Institute, Namakkal – 637 002; 3Veterinary University Training and Research Centre (VUTRC), Karur, 4Department of Livestock Production Management, Veterinary College and Research Institute, Namakkal – 637 002m, Tamil Nadu, India.


Abstract | In modern commercial broiler chicken production, the birds are inevitably exposed to various stress due to rapid growth, intensive poultry rearing, high stock density resulting in diminishing immune competence, gut health etc. This paves way to greater susceptibility of the birds to illness, infection and mortality. To overcome these losses, mostly antibiotics are being incorporated in feed. These antibiotics have possible lead to the emergence and dissemination of multiple antibiotic resistant pathogens and reduction in response to human and animal infections. The ban of antibiotic growth promoters in many countries necessitates to find an alternative to suppress microbial load particularly the gut. Probiotics, prebiotics or organic acids have being included to replace antibiotics. Of which, prebiotics are costlier affecting economics in poultry production, while probiotics have different degrees of survivability in feed and in the gut environment. Organic acids could be the possible choice as alternative to antibiotics. In poultry production, organic acids have not gained as much attention as in swine production (Langhout, 2000).Generally, short chain fatty acids (formic acid, acetic acid, butyric acid) are preferred acidifiers, among which, butyric acid (BA) is considered as the prime enterocyte energy source, necessary for development of Gut Associated Lymphoid Tissue (GALT) (Friedman and Bar-Shira, 2005) and has the highest bactericidal efficacy against the acid-intolerant species such as Escherichia coli and Salmonella sp. (Kwan and Ricke, 2005) with selective stimulation of beneficial gut bacteria.


Keywords | Broiler chicken, Antibiotic substitute, Organic acid, Butyric acid


Editor | Kuldeep Dhama, Indian Veterinary Research Institute, Uttar Pradesh, India.

Received | November 04, 2017; Accepted | January 06, 2018; Published | January 29, 2018

*Correspondence | Kumarasamy Deepa, Department of Animal Nutrition, Veterinary College and Research Institute, Namakkal – 637 002, Tamil Nadu Veterinary and Animal Sciences University, India; Email:

Citation | Deepa K, Purushothaman MR, Vasanthakumar P, Sivakumar K (2018). Butyric acid as an antibiotic substitute for broiler chicken–A review. Adv. Anim. Vet. Sci. 6(2): 63-69.


ISSN (Online) | 2307-8316; ISSN (Print) | 2309-3331

Copyright © 2018 Deepa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Butyric Acid and its Forms

Butyric acid (or butanoic acid or 1-Propanecarboxylic acid or Propanecarboxylic acid,) is a carboxylic acid containing four carbon atoms. BA is available as Na, K, Mg and Ca salts which can used as feed additive,. The advantage of salts over free acids is that, they are generally odour-less and easier to handle the feed manufacturing process owing to their solid and less volatile form. Sodium butyrate (SB) is the most commonly available form.BA has a pKa (4.81) that dissociates in crop.Hence, 90-99 % of the short chain fatty acids are present in the gastrointestinal tract as anions rather than free acids.However, the fat coated BA salts may overcome this problem as it is available even in the lower part of the small intestine (Ashan et al., 2016).Protection can be made either by esterification of BA with glyceride, known as Butyric Acid Glycerides (BAG), or by encapsulation of butyric acid or its salts. These encapsulated products are also referred to as coated butyric acid or coated salts. Of which, encapsulated salts reach the distal sections of gastrointestinal tract at higher concentration (Mallo et al., 2012).


Benefits of Butyric Acid

Antimicrobial effect

Inhibition of pathogenic bacteria by organic acids is by penetration (non-ionized) into lipophilic bacterial cell wall, dissociation at neutral cytosolic pH and releases anions and protons causing lethal accumulation of anions that affects purine bases (Choi et al., 2000), denatures essential enzymes (Roe et al., 2002) and results in bacterial


Table 1: Effect of various forms of butyric acid supplemented at different levels in broiler chicken diet on microbial count of intestinal digesta


Forms of butyric acid

Level of inclusion (%)

Site of intestine where digesta collected

Type of count studied (Result: Reduced (-), Not influenced (NI))


Butyric acid (BA)



Salmonella (-)

Van Immerseel et al. (2004)

Sodium Butyrate(SB)




Van Immerseel et al. (2005)

CSB (Coated sodium butyrate)



Salmonella (-)

Van Immerseel et al. (2005)

CSB and UCSB (Uncoated sodium butyrate)

0.125 and 0.0315 respectively

Salmonella (-)




Escherichia coli (NI)

Hu and Guo (2007)

Lactobacillus (-)




Salmonella (-)

Fernandez-Rubio et al. (2009)


Salmonella (-)




Salmonella (-)


Salmonella (-)


0.1 % + Essential oil


Salmonella (-)

Cerisuelo et al. (2014)

Protected SB



Escherichia coli (NI)

Chamba et al. (2014)


cell death. The in vitro study of microbial count influenced due to organic acid is presented in Table 1. The different forms of butyric acid at various levels studied by several authors showed divergent results of body weight gain, feed intake and feed efficiency (Table 2).Table 3 shows that coated sodium butyrate (CSB), butyric acid glycerides (BAG) or butyric acid (BA) supplementation produces performance similar to antibiotic supplemented group indicating the ability to replace various feed antibiotics.


by supplementation of coated (0.09% and 0.18%) and uncoated sodium butyrate (0.03% and 0.06%), showed performance in terms of body weight gain, feed intake and FCR comparable to Oxytetracycline (50 ppm) supplemented group suggesting the capability to replace the antibiotic. Further, 0.18% coated sodium butyrate (CSB) reduced serum total cholesterol, LDL cholesterol and uric acid, increased serum sodium level, villi height, villi height to crypt depth ratio, villi height to villi width ratio of jejunum. In addition, both levels of CSB reduced duodenal pH, caecal Escherichia coli and Clostridium perfringens count determining that CSB can be a better antimicrobial agent than uncoated sodium butyrate.


Effect on PH of Intestinal Digesta

Supplementation of 0.6% BA reduces the pH of gastrointestinal segments such as crop, proventriculus, gizzard and duodenum (Panda et al., 2009), whereas, ileal pH was not altered by addition of 0.3 % BAG (Mahdavi and Torki, 2009) and 0.03% coated SB (Czerwinski et al., 2012) in broiler ration. Similar comparable caecal pH was also recorded when 0.03 % fat coated SB (Smulikowska et al., 2009) and 0.1 % SB together with essential oil (Cerisuelo et al., 2014) were used in broiler ration.


Effect on Immunity

During the process pathogenesis, an interaction occurs between bacteria and host cells, where, butyrate down regulates expression of invasion genes and decreases the virulence of bacteria. (Van Immerseel et al., 2004). In addition to that, butyrate produces mucin glycoproteins in the intestinal epithelium and increase the defence barrier of colon mucosa (Leonel and Alvarez-Leite, 2012).Butyrate increases serum globulin concentrations and lowers albumin to globulin ratio (Griminger, 1986).Studies showed that, BAG at 0.4 % in broiler ration increased serum total protein, albumin and globulin (Ali et al., 2014) in normal and Eimeria maxima challenged-birds.SB at 0.1 % in broiler ration had no influence of serum total protein in healthy birds but in E.coli LPS challenged birds BA prevented the elevation of the serum total protein (Zhang et al., 2011a).Unlike the above results, BAG supplementation at 0.3 (Mahdavi and Torki, 2009) and BA at 3.0 % (Kamal and Ragaa, 2014) did not influence serum total protein, but in the latter study, serum globulin level was significantly higher.


Effect on Serum Protein and Lipids

BAG at 0.4 per cent in broiler ration significantly increased serum total protein, albumin and globulin (Ali et al., 2014) in normal and Eimeria maxima challenged-birds while SB at 0.1 per cent in broiler ration had no influence of serum total protein in healthy birds but in E.coli LPS challenged birds BA prevented the elevation of the serum total protein (Zhang et al., 2011a). Unlike the above studies, BAG supplementation at 0.3 (Mahdavi and Torki, 2009) and BA at 3.0 per cent (Kamal and Ragaa, 2014) did not influence serum total protein, but in the latter study, serum globulin level was significantly higher.


Table 2: Performance of various forms of butyric acid supplementation at different levels in broiler diet when compared to unsupplemented group


Level of inclusion (%) Body weight gain Feed intake Feed Efficiency Reference
0.1 NI NI Better(4.2)

Smulikowska etal.(2009)





Jerzsele et al. (2012)

0.15 + 0.15 % essential oil (ginger and carvacrol oils)
0.03 - (1.1) NI NI

Czerwinski et al. (2012)

0.03 + 0.06 % salinomycin + (2.5) -(1.9) NI
0.07 + (5.7) NI Better (3.8)

Chamba et al. (2014)

0.1 in starter phase - (7.8) NA NI

El-Ghany et al. (2016)

0.05 in grower phase - (3.9) +(6.2) Poor (9.4)
0.025 in finisher + (0.7) NI Poor (3.3)
0.2 NI NI NI

Leeson et al. (2005)

0.2 + (3.13) NI NI


Antongiovanni et al. (2007)

0.35 NI
0.5 and 1.0 NI

0.3 in starter and

0.2 in grower phase

+ (7.41) -(10.98) Better (17.5)

Taherpour et al. (2009)

0.3 NI NI NI

Mahdavi and Torki (2009)

0.2 - (9.11) - (10.74) Better (2.65)

Mansoub (2011a)

0.2 + (9.9) - (7.2) Better (19.1)

Mansoub (2011b)

0.2 NI NI NI

Jang (2011)

0.3 in 1st week and 0.2 up to 25 days

Sayrafi et al. (2011)


Irani et al. (2011)

0.4 + (15.14) - (6.31) Better (20.7)

Ali et al. (2014)

0.09 in starter and 0.045 in grower -finisher phase + (8.05) + (6.73) NI

Edmonds et al. (2014)

(0.05 in starter and 0.025 in grower -finisher phase) + Humic acid NI NI NI
0.05 + (2.00) NI Better (1.9)

Levy et al. (2015)

0.2 NI NI NI

Hu and Guo (2007)



Zhang et al. (2011a)

0.2 NI + (1.18) NI

Shahir et al. (2013)

0.1 UCSB + Essential oil (Cinnamaldehyde and thymol) NI NI NI

Cerisuelo et al. (2014)

0.6 + (3.31) NI Better (4.8)

Panda et al. (2009)

3.0 + (8.47) Better (8.4)

Adil et al. (2010)

0.5 NI NI NI

Rahmatian et al. (2010)


Aghazadeh and Yazdi (2012)

3.0 + (8.55) NI Better (8.84)

Kamal and Ragaa (2014)

0.3 + (8.19) NA Better (11.5)

Lakshmi and Sunder (2015)

0.25 (starter & grower phase) NI NI NI

Dehghani-Tafti and Jahanian (2016)

0.25 (finisher phase) + (5.29) + (2.32) Better (3.0)


Values in parenthesis for body weight gain, feed intake and feed efficiency indicateper cent increase (+) or decrease (-); Not influenced (NI); Not applicable (NA)


Table 3: Performance of various forms of butyric acid supplemented at different levels in broiler diet when compared to antibiotic supplemented group


Level of inclusion Antibiotics Body weight gain Feed intake FCR Reference
CSB (Coated sodium butyrate) 0.03 % Salinomycin (60 ppm) NI - (6.31) NI

Czerwinski et al. (2012)

CSB - 0.07 % Colistin + (2.63) NI Better (1.70)

Chamba et al.(2014)

Butyric acid glycerides (BAG) 0.4 %


(11 ppm)


Leeson et al.(2005)

BAG -0.2 % Bacitracin methylene disalicyate (50 ppm)
BAG -0.3 % Salinomycin (50 %) NI NI NI

Irani et al.(2011)

0.3 % in first week and 0.2 % up to 25 days of age (BAG)

Bacitracin methylene disalicyate

(50 ppm in grower and 25 ppm in finisher phase)

Sayrafi et al. (2011)

Butyric acid (BA) - 0.6 % Furazolidone (0.05 %) NI NI NI

Panda et al.(2009)

BA-0.5 % Salinomycin (0.5 %) NI NI NI

Rahmatian et al. (2010)

BA- 0.3 %


(11 ppm)

+ (6.55) - Poor (7.6)

Lakshmi and Sunder (2015)


It is well known that acidifiers improve gut health by promoting the growth of beneficial bacteria while inhibiting the pathogenic bacteria. Beneficial bacteria like Lactobacillus sp. havehigh bile salt hydrolytic activity which is responsible for deconjugation of bile salts (Sarono, 2003). Deconjugated bile acids are less soluble, hence less absorbed in the intestine and are more likely to excrete cholesterol and its fractionin faeces (Klaver and Van der meer, 1993) thus reduction of cholesterol accretion in the body. Previous work done by Taherpour et al. (2009), Jang (2011), Mansoub (2011a), Kamal and Ragaa (2014) and Deepa et al. (2017) showed reduced levels of serum total and LDL cholesterol without affecting HDL cholesterol level due to addition of various forms of BA. Similarly, serum triglyceride level was also found to be reduced when BAG was supplemented in broiler ration at 0.2 (Jang, 2011; Mansoub, 2011a) and BA at 0.25 % (Dehghani-Tafti and Jahanian, 2016). Addition of 0.6 (Panda et al., 2009), 0.3 % BA (Lakshmi and Sunder, 2015) in broiler chicken reduced the abdominal fat. While, it was not influenced by inclusion of 0.04 % microencapsulated SB (Zhang et al., 2011b), 0.3 % protected BA (Mahdavi and Torki, 2009), 0.25 (Aghazadeh and Yazdi, 2012) and 0.2 % BAG (Jang, 2011).


Effect on Mineral Absorption

In general, acidification of feed increases calcium absorption in intestine by decreasing the pH of digesta, in turn inhibiting phytic acid from formation of calcium-phytate complex (Boling et al., 2000; Rafacz-Livingston et al., 2005). Butyrate induces absorption of water and sodium (Friedel and Levine, 1992). Earlier works with BAG supplemented at 0.3 (Mahdavi and Torki, 2009) and BA at 3.0 % (Adil et al., 2010; Kamal and Ragaa, 2014) in broiler ration increased serum calcium level. The latter authors also documented increased serum phosphorus (Adil et al., 2010; Kamal and Ragaa, 2014) and magnesium levels (Kamal and Ragaa, 2014).


Anticatabolic Effect

Elevated levels of serum ALT and AST indicates the deleterious effects of liver functions. BA supplementation at 3.0 % (Kamal and Ragaa, 2014; Adil et al., 2010) did not influence the serum Alanine Transaminase (ALT) and Aspartate Transaminase (AST) levels in broilers. In Eimeria maxima challenged-birds, inclusion of BAG at 0.4 % prevented the elevation of serum ALT and AST levels as found in positive control indicating that butyric acid, at times, have the protective effect over hepatocytes (Ali et al., 2014).


Antioxidant Effect

Dietary inclusion of various forms of butyric acid increases serum superoxide dismutase(SOD) activity and decrease malanoldehyde (MDA) content suggesting enhanced the capacity of scavenging free radicals and decreased damage of tissues or cells. Catalase is one of the key defence systems against oxidative stress which is also found to be elevated due to inclusion of various forms of butyric acid. In a study by Zhang et al. (2011a), at day 21, broiler birds supplemented with SB up to 0.1 % elevated serum SOD and catalase, while reduced serum MDA levels. Similarly, supplementation of 0.04 % microencapsulated SB inhibited stress due to corticosterone injection by enhanced catalase activity and decreased MDA level in breast muscle of broiler birds (Zhang et al., 2011b).


Effect on Intestinal Integrity

Frankiel et al. (1994) have shown that short chain fatty acid mixture infusions into the rat isolated caecum caused trophic effects in the jejunum mucosa. Further, an increase in the villus height and villus height to crypt depth ratio are directly correlated with increased epithelial cell turnover (Fan et al., 1997) and an indicator of activated intestinal villi function (Langhout et al., 1999; Shamoto and Yamauchi, 2000) and it also stimulates intestinal blood flow. In addition, butyrate of stimulates cell growth and differentiation of normal cells and apoptosis (early cell death) of tumour cells which represents‘butyrate paradox’ (Canani et al., 2011).Previous studies showed increased jejunum villi height (Adil et al., 2010; Jerzsele et al., 2012; Chamba et al., 2014), villi height to crypt depth ratio (Hu and Guo, 2007; Shahir et al., 2013) and comparable crypt depth (Hu and Guo, 2007; Adil et al., 2010; Smulikowska et al., 2009; Chamba et al., 2014; Sayrafi et al., 2011; Antongiovanni et al., 2007) by supplementation of different forms of butyric acid.


Table 4: Effect of butyric acid oncarcass characteristics in broilers


Inclusion of Butyric acid (%) Parameter influenced Increase (+) or

>Decrease (-)

0.25 Dressed carcass weight +

Aghazadeh and Yazdi (2012), Dehghani-Tafti and Jahanian (2016)

0.6 +

Panda et al.(2009)

3.0 +

Adil et al.(2010)

0.3 Breast meat +

Lakshmi and Sunder (2015)

0.25 Liver weight +

Aghazadeh and Yazdi (2012)


It is clear from the Table 4 that inclusion of BA in broiler diet improves the weight of carcass indicating anabolic effect in broiler chicken.




Butyric acid is thus known to have antimicrobial, anticatabolic and antioxidant effect together improving the lipid metabolism, mineral absorption and immune status of birds. It is also known to improve the carcass characteristics and overall performance of broiler birds. Among various sources of butyric acid, coated form of butyric acid overcomes the odour problems and produces desired outcome by enabling the butyric acid to reach entire gastrointestinal tract effectively.




We wish to thank all the knowledge contributors in this field of study


Conflict of Interest


We don’t have any conflict of interest


Authors Contribution


All authors contributed equally.




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