Sudden Death in Broilers - Metabolic Load on Modern Broilers

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Sudden Death in Broilers - 

Metabolic Load on Modern Broiler Birds


Due to rapid growth rates & weight gain defects in internal metabolism in broilers is inevitable; it manifests in 2 forms (1) SDS (2) Ascites

Its a major problem of broiler industry and more than that its of problem of pain and life which is suffering (one can ask a question why such high growth rates are required?)



Anyways all ages are affected but 4 week old are more susceptible; males are more affected than females;

It have been reported that 70- 80 per cent of male mortality and 20-25 per cent of female broilers chickens mortality could be attributed to acute death syndrome or “Flip-Over Diease”. 
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CVS (Cardio Vascular System) failure is seems to be main and immediate cause

Factors suspected - 
  • Level and type of fats (in diet); 
  • Electrolyte imbalance; 
  • Sudden noise; 
  • High intensity lighting; 
  • Blood clot in heart 
  • also suggest vitamin deficiencies; 
  • managemental causes -  high light intensity (may or may not be a cause bcz many contradicting studies are found); 
  • Stocking density - cuases stress (which release catecholamines adrenaline) 
  • Increase calcium in heart muscle; 
  • Cardiac arrhythmia; Exersice decrease BP. which along with catecholamines cause severe congestion of abdominal organs;


Nutrition - pellet feed; faster growth high incidence of SDS; while pelleting, protein may change to toxic factors (need more investigation), argument given "since reduction in the quantity of soyabean meal in the diet reduced the incidence of SDS";  

Lactic acid  in a study it was found that "100% mortality (SDS type death) is seen" "in broilers by injecting 20 per cent lactic acid solution into the wing vein. Pipetting 5 ml of same lactic acid solution into the crop had less consistent effect but gave high SDS mortality in general" 

Conclusion high glucose/carbohydrate causes SDS type deaths (higher levels of blood lactate); 

Wheat soybean diet causes more SDS than corn soybean diet; protein have very little effect; higher protein diets associated with lower SDS; 

Lactate metabolism - 100% mortality is indicated when lactate level increases 10 times the normal; fast growing broilers have higher proportion of muscles a.c.t visceral organs (get lower supply of oxygen resulting in hypoxia); 

Biochemical Explanation - Lack aerobic metabolism & utilization of NADH2 in glycolytic pathway; lack of oxygen cause pyruvate to convert into lactic acid through lactic acid dehydrogenase - systemic acidosis occurs - that causes fall in blood pH - CVS disturbances - Cardiac arrhythmia arises; lactic acid also produced in crop; if sulphur rich protein is given leads to increase acid secretion causes SDS; 

Prostaglandins - regulate blood flow & nerve transmission to visceral organs, in SDS heart shows little linoleic acid and arachidonic acid hence decrease in the synthesis of prostaglandin which leads to deterioration of membrane structure and cardiovascular disturbances causing increase in SDS;

Correlation between SDS and Ascites - both are metabolic diseases, cardiac involvement & edema are common to both; When condition is acute results in SDS and if condition is chronic it results in ascites.

Clinical Signs :- normal birds suddenly extend their necks,  beat wings & dies (sudden attack prior to death characterized by loss of balance, violent wing flapping and strong muscular contraction); most of birds gave some type of squawk or high pitched cry during the attacks.

PM findings; 

Necropsy reveals the presence of a structure within the blood of the heart. Histologically this structure have been identified as “Jelly clots” or chicken fat clots both of which as PM in origin.
Lung :- Edema of lung
Kidney and liver :- Slightly congested and subcapsular petechial hemorrhage. Heavier liver with fatty infiltration.
Heart :- Firmly contracted with enlargement, ventricles were empty. Atria filled with blood clots. Clot was considered as post-mortem origin.
Crop and Gizzard :- Full of recently ingested food.
Gall bladder :- Empty, indicates birds prior to death eaten up food.

Microscopic lesions

Lung :- Varying degree of vascular engorgement. There is presence of RBCs and edema of intestinal and interlobar connective tissue.
Liver :- At the portal triad, infiltration of leucocytes. there is distortion and reduction of lumen of bile duct.
Heart :- Degeneration of myofibrils, leukocytes infiltration which was lymphocyte and heterophils. There is edema which leads to separation of myofibrils.

Balanced electrolyte supplements and blood buffers (like citrate/bicarbonate) provide sufficient relief from biochemical imbalance along with this herbal antioxidants and Vitamin C. 






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