How to Improve Weaned Piglet Performance Naturally with Organic Acids and Phytogenic Feed Additives

Pig production today has to overcome major challenges, such as reducing the therapeutic use of antibiotics and cutting ammonia emissions. Producers also have to struggle with the inconsistent availability and increasing price of raw materials. Feed formulation is a delicate process that must balance the nutrient requirements of the animal at each stage of production with the nutritional value of various raw materials and ingredients, while bearing price and availability in mind. Sustainable feeding, based on selected feed additives that increase nutrient digestibility and modulate the microbiota, can help to manage gut performance and improve profitability in pig production.

Challenges in pig production

Factors that affect pig performance and productivity include:

  • Genetics
  • Housing (temperature, stocking density, air flow and ventilation, regrouping policy)
  • Health of the animals (birth weight, vitality, immune status)
  • Environment (pathogen load in pens, biosecurity)
  • Water availability (flow rate, quality) and biofilms in water pipes
  • Nutrition (feed components, particle size, dietary fiber, protein content and amino acid balance, energy density, anti-nutritional factors)
  • Presence of mycotoxins and endotoxins (gut integrity, contamination levels, period and extent of intake).

Other stress factors, such as environmental changes, feed changes, vaccinations and transportation, can affect animal health and performance. Feed contaminants like mycotoxins disrupt the barrier function of the gut, creating opportunities for the invasion of bacteria and endotoxins.

Low endogenous acid and enzyme secretion, coupled with an immature immune system, make piglets highly susceptible to infectious diseases. Reduced feed intake and dysbiosis are the result of these challenges, especially after weaning. Post-weaning diarrhea is linked to poor protein digestion and an overload of bacteria in the gastrointestinal tract (GIT). Pathogenic toxins can cause intestinal inflammation, resulting in high energy losses (up to 30%) and negative effects on growth.

Natural feed additives support gut health in weaned piglets

It is very important to find sustainable solutions that combine various strategies to control pathogens like E. coli and clostridia. Strict biosecurity, an appropriate feeding regime and good mycotoxin risk management are all crucial in modern pig production. Feed additives, such as mycotoxin deactivators, organic acids, phytogenics, probiotics and prebiotics, and enzymes, help modulate the GIT, controlling pathogens, supporting the immune system and improving nutrient digestibility. These preventive tools reduce the risk of dysbiosis, inflammation and scour in weaned piglets.

There is growing public concern over the spread of bacterial resistance and its repercussions on animal and human health, so natural feeding strategies that can help reduce the need for antibiotics are highly sought after.

Organic acids in piglet feed

Organic acids are well known for their ability to modulate the intestinal microbiota in pigs, which has a positive effect on gut health and performance, so organic acids are very commonly added to piglet diets.

Free organic acids can:

  • Reduce the microbial and fungal contamination that causes feed spoilage
  • Reduce the buffering capacity of the diet
  • Reduce feed pH
  • Reduce the pH in the upper part of the piglet GIT

The positive effect of acidifiers depends on the type and concentration of the product.

Various studies have demonstrated that acidifying piglet diets can reduce coliform counts throughout the GIT, reducing scours and mortality. Organic acids have a positive effect on the growth of Lactobacillus in the GIT, which may competitively inhibit E. coli proliferation.

Organic acids, e.g., formic, propionic, lactic, benzoic, butyric and acetic acid, are used individually or as a blend in swine diets. The level of dietary acidification and pH reduction depends on the diet's composition and the quantity of organic acid.

Combining various organic acids, and using acid blends instead of individual organic acids, has become increasingly common, as using organic acids in combination broadens their spectrum of activity. The antimicrobial effect of a blend of formic and propionic acids on Salmonella and E. coli was up to 24% better than the efficacy of the individual acids.

There is also growing evidence to suggest that some essential oils or their phytochemical constituents, and permeabilizing substances, can act synergistically with organic acids. The permeabilizers generally have no bactericidal effect themselves, but they can weaken the outer membrane of Gram-negative bacteria and facilitate the action of other antimicrobials on the bacteria. These synergistic effects have been confirmed in Biotronic® Top3 (Figure 1).

Figure 1. Bacterial inhibition by an organic acid mixture (formic acid, acetic acid, propionic acid and cinnamaldehyde) with and without the Biomin® Permeabilizing Complex™
Figure 1. Bacterial inhibition by an organic acid mixture (formic acid, acetic acid, propionic acid and cinnamaldehyde) with and without the Biomin® Permeabilizing Complex™

What makes Biotronic® Top 3 unique?

The Biotronic® product line combines selected organic acids and a phytochemical substance with the unique Permeabilizing Complex™ blend. The special carrier in the solid forms of the Biotronic® Top product line, also called the sequential release medium, starts to release the active substances in the feed, as well as in the GIT. The Permeabilizing Complex™ boosts the activity of the active ingredients in both the product and the feed, and helps them pass through the membrane and into the cytoplasm of Gram-negative bacteria.

In vivo trials confirm efficacy

Several studies have demonstrated that adding a feed additive based on a blend of organic acids and a phytochemical, combined with Permeabilizing Complex™ (Biotronic® Top3, BIOMIN), to piglet diets enabled levels of other acids to be reduced due to its boosting effect. Feed palatability is improved and feed intake by weaned piglets increases.

In a German field trial with 380 weaned piglets, 6 kg of a product based on formic acid salt was replaced by 1.5 kg of Biotronic® Top3 per ton of feed. The feed also contained other standard acids that were included at the same rate for both the trial and control groups. The trial demonstrated that weaned piglet growth improved when potassium diformate in the feed was replaced by Biotronic® Top3. Average daily gain increased by 8.4% and feed conversion improved by 2.1% in the trial group.

Another trial Another trial was carried out at the Center of Applied Animal Nutrition in Mank, Austria: a total of 84 weaned piglets [(Landrace x Large White) x Pietrain] were allocated to 12 pens with seven piglets each (four groups, with three pens per replicate) and were assigned to one of four treatments. All piglets were fed a two-phase diet during the trial period: a starter diet, which was fed from day 0 to day 14, and a grower diet, fed from day 15 until the end of the trial. The trial lasted 49 days. The trial groups and treatments are shown in Table 1.

Table 1. Trial groups and treatments
Table 1. Trial groups and treatments

The results demonstrated that growth was better in the groups given feed supplemented with Biotronic® Top3 alone or in combination with formic acid.

From day 1 to day 27, the average daily gain (ADG) was very similar in the different trial groups (TG), ranging from 359 to 365 g, except in TG III, which had an ADG of 348 g. Between day 28 and day 49, ADG was highest in TG I. Over the whole trial period, the ADG of TG I was 5.2% better than the control group, 1.5% better than TG II and 4.8% better than TG III (Figure 2).

Figure 2. Average daily gain (g) in the four treatment groups
Figure 2. Average daily gain (g) in the four treatment groups

Feed intake per piglet per day was higher in TG I than all the other trial groups. Feed conversion ratio (FCR) from day 1 to day 27 was poorest in TG I; 1.4% higher than the control group and 2.1% higher than TG II and TG III. However, from day 28 to day 49, the FCR of TG I had dropped to the lowest level out of all the treatment groups; 5.4% lower than the control group, 2.8% lower than TG II and 1.7% lower than TG III. Over the whole trial period, FCR was again best in TG I (Figure 3).

Figure 3. Feed conversion ratio in the four treatment groups
Figure 3. Feed conversion ratio in the four treatment groups

Based on the cost-benefit analysis, net income was highest in TG I, resulting in a return on investment of 1:6.85. Moreover, having extra space in the feed formulation allows greater flexibility regarding the inclusion level of raw materials to optimize nutrient levels and costs. Other feed additives can be used to improve growth further and support animal health.

Organic acids + phytogenics = the perfect match to manage gut performance

Organic acids are mainly effective against Gram-negative bacteria but other bacteria often cause post-weaning diarrhea, so it is useful to combine organic acids with other feed additives that can help to control Gram-positive bacteria (e.g., clostridia, staphylococci, streptococci).

Phytogenic feed additives (PFAs) are some of the most common additives to be paired with organic acids. Various PFAs are commercially available in the feed industry, including essential oils, nature-identical products, herbal extracts and their complexes, and their effects on piglets vary, depending on their formula.

In addition to the flavoring and antimicrobial properties of complex PFAs, they also stimulate endogenous enzyme secretion and improve the digestibility of nutrients, especially proteins and amino acids. They can reduce the effects of stress by down-regulating the release of inflammatory proteins and/ or increasing the production of cytoprotective protein.

Complex PFAs reduce inflammatory processes and improve nutrient digestibility

The complex PFA Digestarom® modulates the gut microbiota, has anti-inflammatory and anti-oxidative effects, and improves digestion.

In vitro studies with Digestarom® demonstrate that it inhibits the pro-inflammatory transcription factor NF-kB, counteracting inflammatory processes. It also promotes transactivation of the 'gut protection marker' Nrf2, stimulating antioxidant enzyme expression.

A digestibility study conducted at the Free University of Berlin demonstrated that Digestarom® increased the digestibility of proteins, amino acids and other nutrients in piglets (Figures 4 and 5). Fewer undigested nutrients remained in the GIT, so gut health improved and ammonia emissions were reduced.

Figure 4. Effect of Digestarom® on apparent ileal digestibility of crude protein, fat, starch, calcium and phosphorus
Figure 4. Effect of Digestarom® on apparent ileal digestibility of crude protein, fat, starch, calcium and phosphorus
Figure 5. Effect of Digestarom® on apparent ileal digestibility of amino acids in piglets
Figure 5. Effect of Digestarom® on apparent ileal digestibility of amino acids in piglets


Many factors, such as genetics, management and nutrition, affect health and performance in pigs. Nutritional strategies based on organic acids combined with a complex PFA help to control a wide range of bacteria, limiting their harmful effect on piglets. The Permeabilizing Complex™ blend in Biotronic® Top3 weakens the outer membrane of Gram-negative bacteria and boosts the antimicrobial effect of organic acids and phytochemicals. Organic acids and PFAs are the perfect match in piglet feed, and are effective tools to reduce the need for antibiotics, increase protein digestibility and reduce ammonia emissions.