Fatty liver hemorrhagic syndrome (also referred to as fatty liver syndrome or FLHS), a disease in chickens and other birds. Birds with this disease have large amounts of fat deposited in their liver and abdomen.[1] This often results in an enlarged liver that is easily damaged and prone to bleeding.[2] In some cases the disease is fatal, usually as a result of blood loss from an internal hemorrhage in the liver.[3] The hemorrhage often occurs when a hen is straining to lay her egg.[2] Fatty liver hemorrhagic syndrome is "the major cause of mortality in laying hens."[4]
Causes
Excessive dietary energy intake is believed to be the cause of fatty liver hemorrhagic syndrome.[2] Heredity may also play a role, but it is not the entire cause for the disease.[3] Birds housed in cages will more likely be affected because they are unable to exercise to burn off the extra dietary energy.[2] A 2019 study showed 74% of caged hens died from FLHS whereas only 0–5% of mortalities in hens from cage-free barn or free-range systems were attributed to this condition.[5] Walking hens are less likely to develop this problem. The disease is observed most often in birds that appear to be healthy and in a state of high egg production.[2] As a result, death can occur quite unexpectedly.
Symptoms
Affected birds are usually overweight and may also have pale combs.[1] Generally, however, the disease has few or no symptoms prior to the bird's death.[6]
Treatment
Additional information needed
The use of L-Tryptophan in the diet can decrease the syndrome.[7]
References
^ ab"Fatty Liver Syndrome: Introduction," Merck Veterinary Manual Online, 8th Edition, 2003. Retrieved from Merckvetmanual.com on 2007-03-10.
^ abcde"Poultry: Causes for Fatty Liver Hemorrhagic Syndrome," Mississippi State University Extension Service. Retrieved from Msucares.com on 2007-03-11.
^ ab"Miscellaneous Management Related Diseases," Cooperative Extension Service: Mississippi State University. Retrieved from Msstate.eduArchived 2007-02-20 at the Wayback Machine on 2007-03-11.
^Cherian, G, "Fatty Liver Hemorrhagic Syndrome in Laying Hens: An Investigation into the Role of Dietary Fatty Acids," USDA Current Research Information System (CRIS).
^Shini, A., Shini, S., Bryden, W.L. (2019). Fatty liver haemorrhagic syndrome occurrence in laying hens: impact of production system. Avian Pathology, 48:1, 25-34.
^"Death Occurring In Fowl," GameRooster.Com Disease Diagnostics Aid. Retrieved from Gamerooster.comArchived 2007-02-22 at the Wayback Machine on 2007-03-11.
^Y. Akiba et al, L-Tryptophan alleviates fatty liver and modifies hepatic microsomal mixed function oxidase in laying hens, 1992, Comp. Biochem. Physiol. Vol 102A, N°4, pp 769-774.
