Dysbiosis in the gut of poultry occurs when the balance between beneficial and harmful bacteria in the digestive tract is disrupted. The causes are diverse: from nutritional errors and heat stress to infections and abrupt feed changes. This article answers the most frequently asked questions about how dysbiosis develops, when poultry is most vulnerable, and how you can structurally support the gut health of your flock.
What is the normal condition of the gut in poultry?
The normal condition of the gut in poultry is called eubiosis: a stable, diverse microbiome in which beneficial bacteria predominate. In this state, the intestinal wall functions as an effective barrier, nutrients are efficiently absorbed, and the immune system remains in balance.
In a healthy gut, we see a well-developed villus structure with high villi and shallow crypts. This large absorptive surface ensures maximum utilization of proteins, fats, vitamins, and minerals from the feed. Lactic acid bacteria, such as Lactobacillus species, dominate the microbiota and displace pathogenic bacteria such as Clostridium perfringens and E. coli through competition for nutrients and through the production of organic acids.
Tight junction proteins such as occludin and claudin-1 keep the cells of the intestinal epithelium firmly connected. As long as these proteins are adequately produced, pathogens and toxins cannot penetrate through the intestinal wall. A healthy gut also produces short-chain fatty acids, including butyrate, which serve as an energy source for the intestinal cells themselves and suppress inflammatory responses.
Which factors disrupt the gut microbiome of poultry?
The gut microbiome of poultry can be disrupted by a variety of factors. The most common causes are nutrition-related stress, infections, environmental factors, and management errors. Each of these factors can individually trigger dysbiosis, but in practice they often occur in combination.
The most important disruptive factors are:
- Abrupt feed changes: A sudden transition to a different feed type or a different raw material composition gives the microbiota insufficient time to adapt.
- High levels of non-starch polysaccharides (NSP): Wheat- and barley-rich diets increase the viscosity of the gut contents, which promotes fermentation by undesirable bacteria.
- Heat stress: At high temperatures, blood flow to the gut decreases, the permeability of the intestinal wall increases, and resistance to pathogenic colonization declines.
- Coccidiosis infections: Eimeria species directly damage the intestinal epithelium, clearing the way for opportunistic bacteria.
- Antibiotic use: Although antibiotics combat infections, they simultaneously destroy the protective microbiota, which delays the recovery of eubiosis.
- Poor litter quality and hygiene: Wet litter increases the bacterial pressure in the barn environment and increases the chance of oral uptake of pathogens.
- Stress from stocking density or transport: Physiological stress activates the stress hormone cortisol, which directly undermines gut barrier function.
The combination of several of these factors makes the microbiome particularly vulnerable. A flock that is already under heat stress and simultaneously undergoes a feed change has a considerably higher risk of intestinal dysbiosis than a flock in which only one factor is at play.
How does the mechanism of dysbiosis in the gut proceed?
Dysbiosis in the gut of poultry proceeds via a cascade of interconnected processes. A disruptive factor first weakens the gut barrier or shifts the microbiome composition, after which opportunistic bacteria can multiply rapidly and further destabilize the balance.
The mechanism typically proceeds in the following steps:
- Initial disruption: A trigger such as heat stress, an infection, or a nutritional deficiency reduces the production of tight junction proteins or lowers the production of the protective mucus layer in the gut.
- Increased permeability: The intestinal wall becomes more permeable. Toxins, bacteria, and undigested food particles can now pass the barrier and trigger an inflammatory response.
- Shift in microbiota composition: Beneficial bacteria lose their dominance. Pathogenic species such as Clostridium perfringens benefit from the freed ecological space and the presence of undigested proteins as a nutrient source.
- Local inflammation: The immune response of the intestinal wall activates inflammatory cells, which increases tissue damage and further reduces absorptive capacity.
- Reduced nutrient utilization: Due to damaged villi and a smaller absorptive surface, nutrients are absorbed less efficiently. This leads to poorer technical performance, wet droppings, and a higher feed conversion ratio (FCR).
What makes this mechanism insidious is its self-reinforcing nature. Inflammation causes more tissue damage, tissue damage provides more substrates for pathogens, and pathogens worsen the inflammation. Without targeted intervention, a mild onset of dysbiosis can quickly escalate to clinically visible gut problems.
When is poultry most vulnerable to dysbiosis?
Poultry is most vulnerable to dysbiosis during the early rearing phase, during feed changes, and in periods of heat stress. At these times, the microbiome is not yet fully established or is under increased physiological pressure, causing the gut’s line of defense to temporarily weaken.
In the first weeks of life, the gut microbiome of chicks is still actively developing. Colonization by beneficial bacteria is then still incomplete, giving pathogens relatively easy access. Hygiene in the barn and the quality of the starter feed are decisive in this phase for how the microbiome becomes further established.
In laying hens, there is a second vulnerable moment: the transition to the laying period and the later production phase. Feed changes that coincide with the physiological effort of egg production can put the gut balance under pressure, which manifests as wet droppings and poorer eggshell strength.
Heat stress is a seasonal risk factor that directly affects gut integrity in both broilers and laying hens. When body temperature rises, the body redirects blood flow from the organs to the skin to dissipate heat. The gut therefore receives less oxygen and becomes more susceptible to damage and pathogenic colonization. For drinking water and feed additives that support gut resistance during stress periods, targeted solutions are available.
What are the visible consequences of dysbiosis in poultry?
The visible consequences of dysbiosis in poultry are wet or slimy droppings, reduced growth, a higher feed conversion ratio, and in severe cases increased mortality. These symptoms are the direct result of a disrupted gut function and reduced absorptive capacity.
Veterinary practitioners and poultry farmers typically recognize dysbiosis by a combination of the following signs:
- Wet, watery, or slimy droppings that quickly deteriorate litter quality
- Uneven growth within a flock and greater variation in body weight
- Rising feed conversion ratio without a clear nutritional change
- Pale or damaged intestinal wall visible at post-mortem examination
- Increased mortality, particularly in young animals or after stressful events
- In laying hens: decline in laying percentages and more second-quality eggs
At carcass quality level, dysbiosis translates into a lower dressing percentage, more abdominal fat, and higher drip loss. This has direct economic consequences for the producer, both through higher feed costs and lower returns per animal. Early recognition of the symptoms is therefore essential to make timely corrections.
How can betaine contribute to a healthy gut balance in poultry?
Betaine contributes to a healthy gut balance in poultry by strengthening the integrity of the intestinal wall, reducing oxidative stress, and positively influencing the composition of the gut microbiome. It acts simultaneously as an osmolyte, antioxidant, and methyl donor.
As an osmolyte, betaine helps intestinal cells maintain their fluid balance, even under stress conditions such as heat or infection. This is crucial for maintaining the tight junction proteins occludin and claudin-1, which keep the gut barrier closed. When these proteins are insufficiently produced, the permeability of the intestinal wall increases and the risk of dysbiosis rises.
Betaine also increases villus height and reduces crypt depth, resulting in a larger absorptive surface and better utilization of nutrients. Combined with its antioxidant action, betaine actively protects the intestinal wall against damage caused by infections or heat stress. Studies show that betaine also improves resistance to coccidiosis, one of the most common triggers of intestinal dysbiosis in poultry. More background on the mode of action of this ingredient can be found on the page about betaine.
How Jodoco helps with dysbiosis in the gut of poultry
At Jodoco, we develop scientifically substantiated products that structurally support the gut health of poultry, from the early rearing phase through to the finishing period. Our approach combines natural betaine with organic acids, medium-chain fatty acids (MCFA), and essential oils for complete gut support.
Concretely, we offer the following solutions for dysbiosis in poultry:
- Jodobet: Natural betaine as an osmolyte and methyl donor that strengthens the gut barrier, supports tight junctions, and promotes microbiome balance
- Jodoplume: A liquid combination of betaine, organic acids, and copper for application via drinking water, specifically during heat or coccidiosis stress
- Grovax: A combination of organic acids, butyrate, MCFA, and essential oils that reduces gut inflammation, combats pathogenic bacteria, and fits within a No Antibiotic Ever strategy
- All products are based on natural ingredients, GMO-free, and compliant with EU legislation
Would you like to know which product best suits the specific situation in your barn? Contact us and we will be happy to think along with you.
