A single system, the gastrointestinal tract, is responsible for energy extraction, nutrient utilization and growth. Consequently, the structure required to facilitate the desired function of the gastrointestinal tract makes it the most significant entry point for pathogens and a prominent site for immune responses responsible for preventing poultry diseases.
Gastrointestinal tracts are host to populations of microbes that synergistically capitalize on hard-to-digest dietary components while also releasing nutrients that would otherwise go to waste. Establishing these microbes’ aids bird immunity by inhibiting pathogen colonization within the gut through competitive exclusion. This synergistic relationship is complex, and any shift from homeostasis introduces risk and can cause disruption.
Disruption and dysbiosis can leave gastrointestinal tracts vulnerable to pathogens such as Clostridia perfringens and lead to intestinal inflammation, mucosal barrier damage and clinical disease. Ultimately negatively impacting feed conversion, bird productivity and mortality.
Why is the microbiome important to poultry disease prevention?
In addition to helping birds extract more nutrients critical to mechanisms promoting physiological function, growth and productivity, microbes within the microbiome protect bird health and support immunity. However, one of the most critical impacts of the microbiome is its ability to protect intestinal tissue integrity. Challenges to tissue integrity increase the risk of diseases such as Necrotic Enteritis.
Microbiome populations are variable and can shift by necessity or in response to enteric stress, dietary changes, environment, age and many other factors challenging the status quo. Microbiomes can contain populations of undesirable microbes; in some cases, shifts can occur due to the introduction of new microbial populations. In these situations, pathogens have the opportunity to capitalize and colonize.
How do feed-source pathogens impact the microbiome?
Feed is one of the easiest ways to introduce new microbial populations to the microbiome. After all, feed has a direct line to the gut. However, variable microbial loads and heightened pathogen prevalence in feed can challenge the microbiome, leading to dysbiosis, triggering an immune response, and leaving the bird vulnerable to infection.
High feed microbial loads are associated with an increased risk of high pathogen prevalence. Our lab analyzed over 8000 feed and feed ingredient samples and found that feed microbial loads vary by feed and ingredient type. When specifically evaluating Clostridia perfringens incidence in feed and feed ingredients, we found it to be highly variable, even in finished feeds.
Clostridia occur naturally within poultry gut and are prevalent within poultry production systems. Clostridia perfringens, specifically, is linked to Necrotic Enteritis. Within the literature, Necrotic Enteritis has been attributed to elevated mortality, in some cases by up to 10%, feed conversion increases of 2 to 3 points and body weight reductions ranging from 10% to 20%. Data from a collaboration between Dr. Dan Moore, Colorado Quality Research, and Dr. Enrique Montiel, Anitox, indicates that feeding broilers cleaner feed with lower microbial loads throughout the lifecycle supports broiler growth and feed conversion while also reducing mortality in the face of a Clostridia perfringens challenge.
A balanced microbiome facilitates nutrient extraction, absorption and growth. Conversely, disruption of the microbiome by feed-source pathogens triggers the immune system and partitions energy from growth to survival.
What options exist for feed-source pathogen mitigation?
It is no secret that the poultry industry has spent years implementing and evaluating mitigation strategies designed to control feed-source pathogens and prevent poultry diseases.
Common ones include:
When implemented correctly, heat treatment can effectively reduce feed microbial loads. However, based on Aviagen’s recommendation, for heat treatment to be effective, temperatures must be high and sustained for a long hold time (86°C for 6 minutes). When considering heat treatment for eradication of Clostridia perfringens, this is incredibly important as Clostridia exposure to heat conditions prompts sporulation in order to support survival under periods of stress. Furthermore, heat can also activate Clostridia growth from surviving spores. When used properly, heat is effective against feed microbial loads, however, it does not provide continued protection against recontamination.
Organic acid blends are routinely used in feed hygiene programs and show efficacy at high inclusion rates when containing formic, propionic and acetic acids, even more so when used with heat treatment. However, organic acid blends still don’t provide long-term protection against recontamination.
Pre, Pro and Post-biotics
Pre, Pro and Post-biotics are used to support the establishment of a balanced microbiome.
Prebiotics are compounds intended to be metabolized by desirable members of the microbiome that facilitates the proliferation and colonization of the good bacteria in hopes of preventing colonization of pathogens.
Probiotics, also known as direct-fed microbials, are live microbes that supplement the existing microbiome and contribute to gastrointestinal health.
Postbiotics are microbial metabolites that promote host gut health.
These products work to prevent pathogen disruption by supporting the colonization of microbes contributing to a healthy gut, thereby preventing the colonization of pathogens through competitive exclusion. Establishment of a healthy microbiome upregulates mucin production, with aids in supporting immune responses and increased tight junctions, thereby preventing leakage and pathogen transfer into tissues. Depending on management, stress and pathogen challenge, even the strongest microbiome is vulnerable to population shifts and disruption. The efficacy of pre, pro and post-biotics may be enhanced by controlling the introduction of variable microbial loads and feed-source pathogens.
Feed Sanitizers are used at low inclusion rates and effectively reduce microbial loads in feed. True feed sanitizers remain active in feed and can provide long-term protection against recontamination. Controlling microbial loads and mitigating feed-source pathogens until the point of consumption is essential to preventing pathogen introduction and colonization in the gut.
Microbial contamination and recontamination of feed are nothing new. A body of literature connecting feed-source pathogens to performance challenges and costly poultry diseases continues to grow, making it more critical than ever for producers to understand how to implement effective clean feed strategies best. Preventing poultry diseases by mitigating feed-source pathogens and supporting microflora depends on the producer’s ability to control variable microbial load and eliminate pathogens. Feed-source pathogens are opportunistic, and when exposed to favorable conditions, populations can quickly explode. Therefore, one of the most significant considerations when selecting an effective solution is its ability to work beyond the point of intervention. To truly control feed-source pathogens in poultry production, solutions and strategies must possess a high level of control and prevent feed recontamination until the point of consumption.
Check out our podcast, Frankly Speaking, to hear more about Dr. Moore and Dr. Montiel’s work.