Zum Inhalt
Zur Hauptnavigation

Broiler Performance and Feed Intake

Growth promotion and performance enhancement

A crucial topic for those who rear broiler chicken is how to increase broiler weight using nutrition strategies and growth promoters. 

Good gut health relies on overcoming or avoiding challenges to feed intake, and can be improved with gut performance tools such as novel feed additives.

Good gut health is the best growth promoter.
Franz Waxenecker, Managing Director at BIOMIN

Modern genetics 

Modern broiler chickens (reared for their meat) are the result of millions of years of evolution by means of natural selection, on which artificial selection for commercial objectives has been applied. However, it was in the latter half of the twentieth century that the greatest progress made in chicken genetics. This is a fact that the huge change in the performance of broilers can be greatly attributed to the advancements made in their genetics. 

Feed efficiency

Broilers are among the most efficient feed converting livestock in the world. During the selection process, intensive selection pressures placed on broiler performance traits, such as increased body weight and growth rate. The result was the animals with increased appetite and therefore increased voluntary feed intake per day. 

Modern broilers with such amazing appetite are quite energy efficient too. These two traits help them to have a much faster growth rate compare to their ancestors. The birds with such capacity need to have a super-efficient digestive system. It is known that broilers have a faster rate of small intestinal development and an increased rate of morphological growth compared to slower growing layer birds.

Broilers’ small intestines grow fast in terms of weight than carcass mass. The proper growth and increase of the gastrointestinal tract (GIT) stimulate the feed intake as well. Therefore, regular eating and optimum functionality of GIT in broilers are essential to enhance performance. 

Challenges to feed intake

Any internal or external challenges that lower the feed intake or depress the optimum functionality of GIT in broilers may hugely compromise their performance. Unfortunately, there are plenty of things that may cause the birds not eating as much as they suppose to. Van der Aara, P.J., et.al. (2016) showed these factors in the Figure 1. 

Factors that supress feed intake
Factors that supress feed intake | Source: adapted from Van der Aara et al., 2017

The origin of these supressing challenges can be both nutritional (mycotoxins, ANFs, low digestibility of raw material, etc) or environmental (infections, heat/cold stress, management failure, etc). 

Main factors that suppress broiler feed intake

  • Mycotoxins
  • Anti-nutritional factors
  • Low digestibility of feed
  • Infections
  • Heat/cold stress
  • Management failure

Whatever the origin is, via a cascade of reactions, they may influence intestinal health, causing immune suppression and inflammation and eventually reduce feed intake. The effect might be in the in the lumen or within the intestinal wall. The effect might be even a systemic effect. 


One of the biggest stressors of the gut is mycotoxins in poultry feed. These fungal metabolites hinder proper nutrient absorption, causing damage to the junctional complex in epithelial cells and also overstimulate the bird’s immune system. A typical first reaction of birds towards mycotoxin ingestion is reduce feed intake. 


Viruses, bacteria or parasites are also compromise intestinal health and put the GIT health under considerable pressure. The mode of action of each of these microorganisms is different. However the negative impact is same, which is reduction of intestinal functions (through lesions or reduced villus/crypt ratios).

Nutrient digestibility

Poor nutrient digestibility provides harmful bacteria with more substrate, which in turn cause bacteria proliferation and eventually toxin formation within the GIT. Toxic metabolites put the whole digestive system under pressure and eventually decrease animal feed consumption. 

Environmental and nutritional stress

Environmental stress (heat, cold, transport, etc) as well as nutritional stress (toxins, NSPs, imbalance diets, etc) are also resulting in inflammation of the epithelium and reduced intestinal integrity. Upon such condition, feed intake may decrease substantially. 


Including proper feed additives to broiler feed, in the periods where they are exposed to different challenges might improve intestinal health and thus maintain feed intake in broilers. Therefore, it is essential to provide feed additives that not only directly improve performance, but also reduce stress to GIT of the bird, enhance the integrity of the gut, boosting immune system, reduce bacterial challenges and finally increase nutrient digestibility.

The three main types of feed additives key to improve broiler gut performance and feed efficiency are:

  • Phytogenic feed additives (PFAs)
  • Synbiotics
  • Poultry acidifiers


Scientifically-formulated mixtures of plant-based substances such as those found in herbs essential oils can support efficient feed conversion. 

Recent trial results in Cobb 500 Standard broilers demonstrate the ability of Digestarom® DC, a next generation phytogenic feed additive, to improve performance. Over 42 days, birds fed Digestarom® DC supplemented diets showed a statistically significant improvement in body weight gain (2.470 kg) versus birds fed the control diet (2.353 kg), as shown in Figure 2.

Digestarom® DC improves average body weight gain in broilers
Digestarom® DC improves average body weight gain in broilers | Source: University trial in broilers, Southern Europe, Summer 2016
Digestarom® DC improves feed conversion ratio (FCR) in broilers
Digestarom® DC improves feed conversion ratio (FCR) in broilers |Source: University trial in broilers, Southern Europe, Summer 2016

Feed Conversion Ratios (FCR)

Similarly, a difference was observed in the feed conversion ratios (FCR) of the two groups: 1.72 for control versus 1.69 for the Digestarom® DC group, as shown in Figure 5. Overall, Digestarom® DC supplementation resulted in a 2.83% increase in feed intake, a 4.96% increase in weight gain and a 1.75% decrease in FCR. The efficiency gains translate into direct economic benefits producers.

Acidifiers/Organic acids

The use of a natural poultry acidifier, Biotronic® Top3, has been shown to be comparably effective to avilamycin, an antibiotic often used as a growth promoter in poultry production where regulations still allow, according to several scientific peer-reviewed papers. 


PoultryStar®, a combination poultry probiotic and prebiotic, can support birds’ gut health and uniformity either in a conventional or antibiotic-free feeding system. Discover the results of a trial in India where PoultryStar® improved broiler performance on top of an antibiotic-growth promoter regimen.


Van der Aar, P. J., Molist, F., & van der Klis, J. D. (2017). The central role of intestinal health on the effect of feed additives on feed intake in swine and poultry. Animal Feed Science and Technology, 233, 64–75. 



Related articles