A novel combination of organic acids helps poultry producers realize superior levels of gut health and performance

The link between gut health and bird performance is undeniable. When poultry producers support and encourage gut development from hatching, the bird achieves better performance levels over its lifetime. At its core, gut health refers to nutrient digestion and absorption via a stable microbiome. But there are peripheral benefits to good gut health including better immune function, protection against disease and general bird well-being which also contribute to overall flock performance.

There are a number of ways to boost gut health including making improvements to flock management and litter management, and ensuring the provision of fresh and clean drinking water. Feed additives are a useful tool to support the birds’ intrinsic nutritional requirements. Short chain fatty acids (SCFAs) are typically present in the gastrointestinal tract as a product of the fermentation of non-digestible carbohydrates, amino acids, and proteins. Including additional SCFAs in the diet delivers a range of gut health and performance benefits for broilers including:

  • Improvements in feed hygiene
  • Increased stomach acidification
  • Better pathogen control
  • Modulation of the immune response
  • Improvements to gut morphology and mucosa production

Butyric acid delivers gut health improvements

Butyric acid is accepted as a SCFA that plays a crucial role in gut health. There is a library of scientific information available which supports the role of butyric acid in improving animal performance due to its positive effect in the gut. Blaak et al. (2020) describe the modes of action as:

  1. Directly impacting the epithelial function by providing energy to epithelial cells, supporting electrolyte transport, and regulating pH
  2. Promoting mucus production and hence supporting the stability of the barrier between epithelial cells and the outside
  3. Impacting the intestinal barrier function by supporting epithelial cell integrity, reducing permeability, and promoting tight junction expression
  4. Positively affecting mucosal immune function
  5. Inducing expression of antimicrobial proteins (defensins and cathelicidins)
  6. Affecting the enteric nervous system with an apparent impact on the motility of the epithelial cells

Even though the role of butyric acid is well-established, scientific research continues in order to further our understanding. That research has led to the recent discovery of the importance of valeric acid. 

Valeric acid: the latest piece in the organic acid puzzle

Valeric acid is gaining attention in a number of fields, including human medicine. Various in vitro and in vivo studies (in mice) have shown that valeric acid is capable of preventing inflammation and maintaining gut integrity. Its property as a histone deacetylases inhibitor (HDI), as used in psychiatry and neurology, is attracting more attention for use in treatments against cancer, parasite infections and inflammatory diseases. 

In poultry production, valeric acid (in its esterified form) has shown to have a positive effect on the intestinal structure of broilers by increasing the production of GLP-2, a peptide which is considered to have an important role in promoting intestinal growth and function. Another study reported a reduction in lesion scoring and mortality after a Clostridium perfringens challenge when valeric acid was included in the diet. So, what happens to broiler performance when you combine butyric acid with valeric acid in the feed?

Discovering new levels of broiler performance with valeric acid

A study was conducted to evaluate the effects of the combination of butyric acid and valeric acid (Gastrivix™ Avi, Perstorp) on the growth performance of broilers. The trial was conducted at the Institute of Poultry Management & Technology in India and used 3250 as-hatched, day-old Vencobb 430Y chicks divided into four dietary treatment groups (with eight replicates/treatment and 110 birds/replicate). The treatments are shown in Table 1. Feed refusal and body weight were measured weekly until the end of the trial (day 42). On days 4, 28 and 42, one bird per replicate (eight birds in total) was randomly selected from each pen and euthanized for jejunum and ileum morphology analysis. The results are shown in Table 2.

Table 1. Treatment overview

Treatment group Treatment 
 T1 Basal control diet (corn/soybean meal)
 T2 T1 + Bacitracin Methylene Disalicylate (BMD) at 500 g/MT
 T3 T1 + butyric acid / valeric acid combination at 500, 500 and 250 g/MT in the starter, grower, and finisher phases, respectively
 T4 T2 + butyric acid / valeric acid combination at 500, 500 and 250 g/MT in the starter, grower, and finisher phases, respectively

Table 2. Comparison of performance parameters and jejunum and ileum villi length and crypt depth in broilers fed different dietary treatments


FI (kg/bird)

BWG (kg/bird)


Mortality (%)


Jejunum villi length (µm)

Ileum villi length (µm)




1.70a± 0.054





























(Source: Li et al. Australian Poultry Science Symposium  (2023)

The results of the trial show that performance in the broilers fed a diet containing a combination of butyric and valeric acid (T3) was at least as good, if not better for some parameters, as the performance of the broilers fed diets containing the antibiotic Bacitracin Methylene Disalicylate (BMD; T2). In both groups, feed conversion rate (FCR) was improved by 6 points compared to the control group (T1). Body weight gain (BWG) was 0.1 kg in the BMD group, and 0.18 kg in the butyric/valeric acid group, both significant improvements compared to the control treatment group. 

Broilers fed the diet containing butyric and valeric acid in addition to in-feed BMD showed further improvements in growth performance and feed efficiency over and above the BMD treatment alone, as shown by an 11-point improvement in FCR and an increase in BWG by 0.27 kg. These improvements are the result of the improved gut morphology in the small intestine which increases nutrient absorption efficacy.

A novel combination of organic acids delivers more performance

Continuing to investigate the role played by organic acids in poultry diets has uncovered a new piece of the puzzle. Poultry producers can now include a novel combination of butyric and valeric acid in their diets, with or without an antibiotic, and realize even better performance from their flock due to the improvements in gut morphology. The intestinal growth effects of butyric acid and the anti-inflammatory benefits of valeric acid support the animals ability to better use the fed energy to grow. 

References are available on request.

Antonia Tacconi

Global Product Manager Gut Health

Contact me

Antonia Tacconi

Global Product Manager Gut Health

Contact me