New Scientific Results on Natural Growth Promotion in Broilers vs. An Antibiotic Growth Promoter


Reducing the use of antibiotics, as well as replacing antibiotic growth promoters, is a very important objective. To implement and succeed with such an intention, it is mandatory to consider all of the main factors that can influence the performance and health of the animals (e.g. proper management, vaccination protocols, water quality and the correct nutritional formulation).

There are many alternatives to antibiotics available on the market. Most alternatives target gut health and function, and immunity as well as modulation of gut microbiota and inhibition of pathogen proliferation. With such a range, it can be very difficult to understand their mode of action, choose, and combine the right products. The three most important types of feed additive that are integral to any program to improve gut performance are:

• Phytogenic feed additives (PFAs)
• Synbiotics
• Organic acids

PFAs enhance feed efficiency and gut protection. Synbiotic products improve immune status and help to colonize the gut with beneficial bacteria. And organic acids fight against the uncontrolled proliferation of pathogens.

Biotronic® Top3: the enhanced organic acid

The use of organic acids or single chain fatty acids (SCFA) has recently become more and more attractive, not only to improve feed hygiene by reducing feed pH and positively influencing buffer capacity, but also to support gut health. Organic acids can have a direct antimicrobial effect on many pathogens (e.g. Salmonella spp, E. coli) preventing an uncontrolled proliferation of pathogenic bacteria in the gastrointestinal tract. Furthermore, SCFAs contribute to gut health indirectly by improving digestibility. This ensures proper feed digestion, meaning that less undigested feed is present in the lower part of the intestine. This undigested feed may be used as a source of energy by opportunistic bacteria to consequently outgrow the beneficial bacteria, creating intestinal dysbiosis.

The control of pathogenic bacteria is even clearer when Biotronic® Top3, an enhanced organic acid feed additive, is used. Biotronic® Top3, an innovative formulation for better management of Gram-negative pathogens, combines a Permeabilizing Complex™ (a phytogenic substance and a blend of other substances that are able to permeate the outer membrane of Gram-negative bacteria) with the beneficial effects of organic acids. This special blend ensures that the antimicrobial activity of SCFAs have an optimal effect in the animal gut.

Table 1. Trial groups and diets

A science-backed solution

Scientific peer-reviewed papers (Palamidi et al., 2016; Palamidi and Mountzouris, 2018) demonstrated how Biotronic® Top3 added to broiler feed positively affects the key gut ecosystem elements, improving performance. In a trial carried out in cooperation with the University of Athens, Greece, the use of Biotronic® Top3 was compared to the use of avilamycin, an antibiotic often used as a growth promoter in poultry production where regulations still allow. The birds (Cobb) received a corn-soybean basal diet formulated according to a three-phase feeding regime for 42 days. The four experimental treatments are listed in Table 1.

The results clearly indicated that the use of Biotronic® Top3 improved nutrient digestibility and thereby performance in a similar manner to avilamycin. Although nutrient digestibility was improved in both the BTR and the BTPC groups, the same effects cannot explain both of these improvements. Analysis of many different parameters revealed differences in the mode of action of the enhanced organic acid based feed additive and the antibiotic growth promoter.

The use of avilamycin and Biotronic® Top3 had no significant effect on the concentration of total bacteria, Bacteroides spp., Lactobacillus, E. coli, C. leptum and C. coccoides subgroups in the ileal digesta and ileal mucosa associated bacteria. However, the use of avilamycin significantly reduced the concentration of the Clostridium perfringens subgroup in the ileal digesta. This is not particularly surprising, as avilamycin is known to inhibit the growth of Gram-positive bacteria. On the other hand, avilamycin did not affect either the bacterial population in the cecal digesta or the mucosa-associated bacteria in the cecum.

Biotronic® Top3 significantly increased the concentration of C. leptum and C. coccoides subgroups in the cecal digesta. These two bacteria synergize with other intestinal microbiota and ferment unabsorbed dietary carbohydrate into SCFAs, mainly butyrate and propionate. These two SCFAs are the major energy source for the colonic epithelium and profoundly influence intestinal epithelial function. Hence, by stimulating the growth of these two bacterial subgroups, Biotronic® Top3 indirectly influences gut health, having a positive impact on broiler growth performance. Confirming these positive effects was a significant increase in the BTR group of microbial glycolytic enzymes in the ileal digesta, which are associated with better starch digestibility.

A holistic approach that includes proper management, proper vaccination protocols and the correct nutritional formulation is required in order to replace antibiotic growth promoters in commercial poultry production units.

Table 2. Performance results of the trial
Table 3. Cost-benefit analysis of the study groups; Broiler price* = €1.15/kg; Feed price* = €0.33/kg

The improvement of beneficial bacteria growth as well as the promotion of better microbial enzyme activities related to the use of Biotronic® Top3 resulted in better nutrient digestibility, thus improving the performance outcome of the trial (Table 2). This proves that although the mode of action of enhanced organic acids differs from that of antibiotics, enhanced organic acids can be successfully used in a program that aims to reduce the use of antibiotics in animal production.

Biotronic® Top3: a profitable solution

An economical comparison between the cost of the antibiotic solution and Biotronic® Top3 shows that with the use of organic acids it is possible to reduce the gap generated when antibiotic growth promoters are removed from the diet. At an average market price of €1.15/bird, the use of Biotronic® Top3 resulted in an additional net income of €0.22/bird, with a return on investment of 7.83:1 (Table 3).


However, the simple replacement of antibiotics with feed additives is not enough. A holistic approach that includes proper management, proper vaccination protocols and the correct nutritional formulation is required when replacing antibiotic growth promoters in commercial poultry production units. The use of feed additives like Biotronic® Top3 can be a helpful tool for implementing an antibiotic-free feeding program. The product allows the antibiotic to be replaced, while maintaining good performance levels at a low to moderate breakeven point.

In Brief:
  • Antibiotic use for the prevention of disease will likely be banned as a result of increasing consumer demands and regulatory pressure.
  • Simply removing antibiotics from poultry diets will open up a performance gap caused by challenges from pathogens.
  • Biotronic® Top3, an enhanced organic acid, bridges the performance gap by improving the digestibility of the feed and indirectly promoting gut health.


Palamidi I., Paraskeuas V., Theodorou G., Breitsma R., Schatzmayr G., Theodoropoulos G., Kostas F. and Mountzouris C.K. 2016. Effects of dietary acidifier supplementation on broiler growth performance, digestive and immune function indices.
Animal Production Science 57(2). DOI: 10.1071/AN15061

Palamidi I. and Mountzouris C.K. 2018. Diet supplementation with an organic acid based formulation affects gut microbiota and expression of gut barrier genes in broilers. Article in Press. DOI: 10.1016/j.aninu.2018.03.007