AGP Replacement Tools Are Ready For Action

Photo: donskarpo
Photo: donskarpo

More intensive industrial production has placed greater demands on birds and given rise to several challenges related to gut health, including unspecific dysbiosis problems, reduced nutrient digestibility and impaired barrier function. These issues put pressure on farm profitability and explain, at least in part, the motivations for sub-therapeutic application of antibiotics for disease prevention and growth promotion.

A recent scientific study notes that the poultry industry’s global consumption of antibiotic growth promoters (AGPs) is three times higher than that of cattle: 45 mg/kg vs 148 mg/kg (Van Boeckel et. al. 2015). Without indicating any relationship between resistance level and antibiotic usage, Teillant and Laxminarayan (2015) point out that recommended dosage of sub-therapeutic antibiotics has increased over last 60 years, from 10–20 g/ton in the early 1950s to 40–50 g/ton in the 1970s, to 30–110 g/ton nowadays.

New ways to promote growth

The experiences in countries that were early to adopt AGP bans, such as Sweden in 1986 and Denmark in 1998, demonstrate that while a move to antibiotic-free production is not without short-term challenges, these can be overcome and flock performance can reach even higher levels. Replacing AGPs relies upon a holistic approach to improve animal health status and performance through better management, biosecurity measures, vaccination programs, diagnostics and feeding strategy.

Since feed costs account for a significant part (up to 70%) of total production costs, feeding strategy is a crucial point. Organic acids, phytogenic feed additives (botanicals, or PFAs), probiotics (direct-fed microbials, or DFMs) and prebiotics have all been identified as potential in-feed antibiotic replacements. They work in different ways (various modes of action) in order to prevent the proliferation of harmful bacteria, to promote health and immune status, and to enhance animal performance, e.g. by influencing a bird’s anti-inflammatory response.

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Comparable or better results

Significant effort has been paid to identifying which additives will be able to reduce usage of AGPs. In general, novel growth promoters (NGPs) should perform roughly equally as well under practical conditions in order to gain acceptance.

Looking across 25 broiler trials performed in various countries worldwide and testing both AGPs and NGPs (phytogenics, organic acid-based products or microbials) at a variety of production stages, each NGP group performed similar on average in terms of FCR and ADG compared to the AGP group (Figures 1 and 2).

Figure 1. Feed conversion ratio comparison (number of trials).
Source: BIOMIN 2016

The feed conversion ratio (FCR) showed an average improvement of 0.05 in the phytogenic supplemented group versus the AGP (control) group in 14 trials. This may be due to the fact that phytogenic feed additives (PFAs) tend to improve digestion and an animal’s anti-inflammatory and anti-oxidative status, directing more energy towards growth. The organic acid-based additive delivered a 0.01 FCR improvement versus AGP groups averaged over 5 trials. One potential explanation relates to the additive’s antimicrobial effect that supports feed and water hygiene, the control of gram-negative bacteria, and overall reducing the total bacterial load. Microbials (probiotics) delivered an FCR 0.02 higher than the AGP supplemented group across 6 non-challenge trials. The mode of action of direct-fed microbials (DFMs) serve to reinforce a healthy gut microbiota, and improving gut immune function, having an effect on growth mostly in challenging production conditions.

In terms of average daily gain (ADG) of birds, the grams per day figures of the acidifier and microbial groups were similar to the AGP groups (Figure 2). The phytogenic supplemented group recorded a slight improvement (1.5%) compared to the AGP group. Average daily gain (ADG) can positively influence the final weight of the animals and number of rotations, resulting in higher income.

Figure 2. Average daily gain comparison (number of trials).
Source: BIOMIN 2016

Absolute mortality in NGP groups were lower on average compared to the AGP groups (Figure 3). The greatest improvement was observed in the microbial supplemented groups in 6 trials where mortality was reduced more than 30% versus AGP groups. Mortality in phytogenic and organic acid based product groups were 12.3% and 1.3% lowered compared to AGP groups, respectively.

Figure 3. Relative mortality comparison (number of trials).
Source: BIOMIN 2016

Identifying the right tool

These results suggest that flock performance can be maintained with natural growth promoters and that these can be considered an important tool in antibiotic reduction strategies. However, it appears obvious that various NGPs have differing modes of action, needing to be supplemented at the right time and/or in the correct combination, depending on the specific challenge the animals encounter throughout production.

The aim of NGPs should always focus on disease prevention, not treatment. Species, production phase, farm conditions, product dosage and ROI considerations all influence the choice of feed additive.

Furthermore, combinations of additives have been demonstrated to work successfully in particular situations to achieve specific objectives or to counter challenges such as mycotoxins or pathogenic bacteria. This means that organic acid-based products, microbials and phytogenic feed additives may each play a role in future production as part of a tailor-made solution to help producers achieve bird health and performance goals.