Feed Passage Syndrome in Poultry

Feed passage syndrome, also known as “undigested feed passage,” occurs when partially or fully undigested feed appears in the droppings of poultry. This condition is often a symptom of underlying gut health issues that disrupt digestion and nutrient absorption, and it can lead to reduced feed efficiency, slower growth, and other economic losses in poultry production.

Causes of Feed Passage Syndrome:

Several factors can contribute to feed passage in poultry, including:

1. Dysbacteriosis: An imbalance in the gut microbiota disrupts normal digestion as enzymes produced by the bacteria also aid in digestion of the nutrients in the gut. Hence, dysbacteriosis often leads to poor feed breakdown and undigested feed in droppings.
2. Coccidiosis: This intestinal parasite damages the gut lining, alters the structure of the gut, erodes the intestinal epithelium leading to reduced nutrient absorption and bloody diarrhoea with undigested feed particles.
3. Feed Quality: Diets with low nutrient density lacking in digestible nutrients or improperly formulated feed can overwhelm the digestive system, causing incomplete digestion. A balanced feed is required as over supply of nutrients is also detrimental to gut health and proper digestion.
4. High Fiber Content: Diets high in indigestible Fibers can speed up gut transit time, leading to feed passage syndrome.
5. Mycotoxins/anti-nutritional factors: Toxins produced by certain moulds or anti-nutritional factors present in the feed can cause inflammation of the gut lining and damage it , impairing digestion and nutrient uptake.
6. Enzyme Deficiency: Enzymes are crucial for breaking down feed components like proteins, fats, and carbohydrates. As the enzymes produced by the bird and bacterial enzymes produced by the gut microbiota are not enough, enzymes are also added as feed additives. Enzyme deficiency, whether due to diet or gut health issues, can lead to undigested feed.
7. Stress and Rapid Transit Time: Environmental stressors (e.g., high environmental temperature increases water consumption and thereby speeds up gut transit time), and sudden dietary changes also causes undigested feed to appear in the droppings.
8. Hardness / Fineness of feed: Inappropriate durability of the feed also causes changes in rate of gut movement leading to undigested feed in the droppings.
9. Poor Bio-security: If bio-security measures are not adequately adopted, the environmental bacterial load increases in the system that gets into the gut and thereby disturbs eubiosis, Ultimately, the gut health is impaired due to increased load of pathogens and leading to high quantity of undigested feed passage.

Clinical Signs of Feed Passage Syndrome:

Birds with feed passage syndrome exhibit specific symptoms, including:

• Undigested Feed in Droppings: This is the most characteristic sign, with noticeable feed particles like grains and fiber appearing in feces.
• Diarrhoea and Wet Droppings: Watery feces are common, as poor digestion often leads to intestinal inflammation, increased water consumption and faster passage through the gut.
• Poor Growth and Feed Conversion: Since nutrients are not fully absorbed, affected birds will suffer from deficiency of required nutrients and hence, will show reduced growth rates/  require more feed to gain weight leading to poor feed conversion efficiency.
• Increased Feed Intake with No Weight Gain: Birds may eat more to compensate for the lack of nutrient absorption, but this does not lead to the expected weight gain.
• Dirty birds, discolored feathers, increase in water: feed ratio, wet litter, poor air quality, uneven growth, increased mortality etc.,

Economic Impacts:

Feed passage syndrome can result in severe economic challenges:

1. Increased Production  Cost: Due to feed passage wastage of feed and nutrients through faeces is more and birds take further more feed to meet out its requirements and for performance which ultimately increases production cost 
2. Reduced Growth Rates: Affected broilers may take longer to reach market weight, which can disrupt production schedules
3. Poor litter Quality: Watery droppings will lead to poor litter and air quality, due to excess ammonia production and  bacterial load in the environment, higher level of culls and increased mortality.
4. Healthcare and Management Costs: Managing underlying causes, such as coccidiosis or dysbacteriosis, may require medication, additional biosecurity measures, better supervision and more labor.
5. Poor Meat and Egg Quality: Birds experiencing malnutrition due to poor nutrient absorption may produce lower-quality meat and eggs which will bring down their grades in the market leading to less monetary realisation.
   
   Management and Prevention Strategies:

Addressing feed passage syndrome requires identifying and managing the underlying causes. Here are some key approaches:

1. Optimize Diet Formulation: Ensuring balanced, high-quality feed with digestible protein, fat and carbohydrates with adequate levels of vitamins, minerals and any other gut health enhancers can reduce the risk of feed passage.
2. Use of Enzymes: Adding enzymes like Xylanases or Proteases or any other carbohydrases that can improve digestion, especially if there are ingredients in the feed that poultry struggle to digest as even under normal circumstances, only 80-90% of feed ingredients are digested.
3. Coccidiosis control: Implementing an appropriate coccidiostat  management program can protect gut integrity and improve nutrient absorption. One has to show extreme caution in selection of anti-coccidial chemicals keeping in mind the need to follow a rotation policy and also possible interactions with other additives being used.
4. Improve Gut Health with Additives: Feed additives like gut health enhancers can support a balanced microbiome in the gut and improve its health as bacterial enzymes produced by favourable bacteria aid in digestion and bacterial toxins produced by pathogenic bacteria cause inflammation of the gut and impair digestion.
5. Broad spectrum natural Bio-polymer: Concept of the bio-polymer with broad spectrum anti-bacterial, anti-inflammatory and immune modulation properties is getting popular in reducing gut impairment and tackling feed passage syndrome.
6. Reduce Stress and Environmental Factors: Managing temperature, ventilation, stocking density, and other stressors effectively can help maintain stable digestion and reduce transit time issues.
7. Monitor and Control Mycotoxins: Effective monitoring of feed ingredients quality and their storage conditions, using mycotoxin binders in feed etc., can prevent mycotoxicosis and the associated gut damage.
   
   Conclusion:

Feed passage syndrome is a sign of impaired digestion and nutrient absorption, often due to underlying gut health issues or dietary imbalances. Managing this condition through diet optimization, gut health support, and preventive measures can help improve feed conversion, promote growth, and reduce economic losses in poultry production. Early intervention and routine monitoring are essential to maintain a healthy flock and efficient production system.