Identity

A non-infectious metabolic disorder of caged laying hens driven by excessive dietary energy and restricted movement. Massive de novo lipogenesis leads to hepatic lipid accumulation, weakening the liver structure until abdominal pressure causes fatal liver rupture and hemorrhage.

Overview

Fatty Liver Hemorrhagic Syndrome (FLHS) is a major cause of non-infectious mortality in caged layer facilities. Estrogen stimulates hepatic lipogenesis for yolk production, but excess dietary carbohydrates and lack of exercise overload the liver. The fat content can reach 70% of dry matter, making the organ friable. Straining during egg laying ruptures the liver capsule. Mortality spikes during hot summer months due to lower maintenance energy needs. Management requires strict feed intake control, replacing carbs with lipids, and supplementing lipotropic agents (choline, methionine, Vitamin B12).

Structured Facts

Classification

Metabolic > Non-Infectious

Epidemiology

• Prevalence in India: Highly prevalent in caged layer systems
• Severity: Medium to Major
• Affected Species: Poultry (Caged layers)
• Affected Age: Layers past peak production (> 35 weeks of age)
• Transmission: Non-infectious
• Seasonality: Mortality peaks during hot summer months
• Mortality: 3% to 5% (up to 10% in summer); causes up to 74% of total cage mortality
• Morbidity: High (subclinical obesity)
• Economic Importance: Major cause of non-infectious mortality

Clinical Signs

• Early/Intermediate: Birds are overweight, pale combs
• Advanced: Sudden mortality with no premonitory signs. Targets Reproductive, Cardiovascular, and Hepatic systems.
• Postmortem Findings: Large clotted blood masses in abdominal cavity. Liver is enlarged, pale-yellow, soft, greasy, friable, with extensive subcapsular hemorrhages. Large abdominal fat deposits.

Diagnosis

• Field Diagnosis: Sudden death of heavy layers; internal bleeding from liver
• Laboratory Tests: Hepatic lipid content analysis; histopathology showing diffuse fatty infiltration and architectural disruption
• Differential Diagnosis: Inclusion Body Hepatitis, Lymphoid Leukosis

Treatment

• Immediate Actions: Restrict energy intake
• Supportive Care: Vitamin therapy
• Medicines: Lipotropic agents (Choline, Methionine, Vitamin B12), L-tryptophan
• Withdrawal: Not applicable

Prevention

• Vaccination: None
• Biosecurity: Not applicable
• Farm Management: Avoid overfeeding; restrict feed intake during early lay (22-30 weeks); replace dietary carbs with lipids; restrict energy during hot weather

Quantitative Data

• Mortality Rate: 3% to 5% (up to 10% in summer)
• Target Age: > 35 weeks
• Hepatic Lipid Content: 50% to 70% of dry matter
• Housing System: Accounts for up to 74% of mortality in cages vs 0-5% in cage-free

Relationships

• Vaccines: None
• Medicines: Choline, Methionine, Vit B12
• Breed Susceptibility: Caged Layers
• Predisposing Factors: High environmental temperatures, high carbohydrate diets