Phytogenic feed additives (PFAs), categorized as sensory and flavoring compounds, consisting mainly of volatile and non-volatile plant extracts and their active compounds, have traditionally been used in human nutrition, in medicine or even for food preservation.
Their increasing popularity in modern poultry production stems from the fact that their effects in birds can result in better growth promotion that is comparable or better than antibiotic growth promoters (AGPs).
Effects in birds
Many different plant derived substances are known to have antimicrobial, antiviral and/or antioxidant properties. These beneficial properties of PFA are mainly due to their bioactive molecules. Phenolic compounds such as thymol, carvacrol and eugenol and their methyl ethers have strong antiseptic effects. Strong antioxidative properties are for example appointed to species of the families Apiaceae and Lamiaceae, such as caraway and peppermint, respectively. Additionally, specific plant compounds can improve digestibility by supporting digestive secretion such as bile, mucus and saliva as well as enhancing enzyme activity.
Commercial trial results
In a meta-analysis looking across 14 broiler trials performed in various countries worldwide comparing performance results of birds receiving either an AGP or a PFA, each PFA group performed similar on average in terms of feed conversion ratio (FCR) and average daily gain (ADG) compared to the AGP group.
The FCR showed an average improvement of 5 points in the phytogenic supplemented group versus the AGP (control) group, as shown in Figure 1. In terms of ADG, the phytogenic-supplemented group recorded a slight improvement (1.5%) compared with the AGP group, as shown in Figure 2.
Figure 1. FCR results across 14 broiler trials comparing AGPs and PFAs
Figure 2. ADG results across 14 broiler trials comparing AGPs and PFAs
Overall, these results show that specific PFAs can enhance nutrient digestibility and beneficially modulate the intestinal microbiota. PFA are capable of promoting intestinal health and gut performance, which is crucial for optimal profitability.