Fatty Liver Syndrome in poultry is under-diagnosed

When are layers at risk to develop FLS?

Despite good knowledge being available on laying hen nutrition, fatty liver syndrome in poultry cannot completely be prevented in highly productive layers. Fatty livers in poultry can occur at two different moments in the laying cycle:

  • During peak production, young laying hens are not always able to increase their feed intake to such a level that it meets the energy requirements for egg production. As a result, they will start to convert carbohydrates to fatty acids, a process which takes place in the liver. If transport of fatty acids out of the liver can’t match production, fat starts to accumulate in the liver, resulting in FLS.
  • At the end of the laying cycle, lower egg production results in lower energy requirement of the birds. If feed intake is not reduced, excess carbohydrate is metabolised into fatty acids in the liver. This may result in an increase in fat deposition in the liver, resulting in FLS.

How to recognise FLS?

Fatty liver syndrome may be present in your flock if you observe a sharp drop in egg production and mortality. Fatty liver in poultry can result in the following symptoms:

  • Pale comb
  • Performance failure
  • Sunken eyes
  • Mortality
  • Drop in egg production
  • Increased amount of abdominal fat
  • Increase in body weight

How to control FLS?

FLS is one of the most important metabolic disorders observed during high production periods or at the end of the laying cycle of hens. Several factors can cause increased deposition of fat in the cells of the liver.

How to calculate the economic impact of FLS?

To calculate the economic impact of an outbreak of FLS per 1000 hens, the following assumptions have been made: 

  • Egg price of €0.06 per egg
  • Pullet price of €3.80 per head for pullets at the age of 17 weeks
  • Value of the pullet goes down to zero during the laying period

The drop in laying percentage and the mortality chosen in the examples are typical for FLS outbreaks under field conditions.

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