Fatty Liver Hemorrhagic Syndrome in the Backyard Chicken

Abstract

Fatty liver hemorrhagic syndrome, characterized by sudden death in overconditioned hens due to hepatic rupture and hemorrhage, is one of the leading noninfectious idiopathic causes of mortality in backyard chickens. Nutritional, genetic, environmental, and hormonal factors, or combinations of these, have been proposed yet not proven as the underlying cause. In an attempt to characterize the hepatic changes leading to the syndrome, this retrospective case study examined 76 backyard chickens that were diagnosed with fatty liver hemorrhagic syndrome between January 2007 and September 2012 and presented for necropsy to the diagnostic laboratory of the California Animal Health and Food Safety Laboratory System. A majority of the birds were female (99%), obese (97.5%), and in active lay (69.7%). Livers were examined histologically, and the degree of hepatocellular vacuolation (lipidosis), the reticular stromal architecture, the presence of collagenous connective tissue, and vascular wall changes were evaluated and graded using hematoxylin and eosin, Gomori's reticulin, oil red O, Masson's trichrome, and Verhoeff-Van Gieson stains. Interestingly, there was no correlation between lipidosis and reticulin grades; hepatocellular lipidosis was absent in 22% of the cases and mild in 26% of the cases. Additionally, there was evidence of repeated bouts of intraparenchymal hemorrhage before the acute "bleed-out" in 35.5% of the cases. These data are not supportive of the previously proposed causes and provide a framework for future studies to elucidate the pathogenesis of this condition. Furthermore, the data shown in this study support hemorrhagic liver syndrome as a more accurate name, as hepatic lipidosis is absent in a significant proportion of ruptured livers.

Biosecurity Strategies for Backyard Poultry: A Controlled Way for Safe Food Production

“…Necropsy findings in FLHS include abundant coelomic fat and an enlarged, tan to yellow, friable liver with hemorrhages. Another study revealed absence of hepatocellular lipidosis in 22% of the FLHS cases and mild hepatocellular lipidosis in 26% of the FLHS cases in the backyard birds (Trott et al, 2014).…”

Improving effect of dietary soybean phospholipids supplement on hepatic and serum indexes relevant to fatty liver hemorrhagic syndrome in laying hens

“…; Trott et al . ). It was reported that 74% of the total mortality in caged layers was due to FLHS in Queensland, Australia (Rozenboim et al .…”

Pathology and molecular characterization of recent Leucocytozoon caulleryi cases in layer flocks

“…Unfortunately, these characteristic gross findings could also indicate fatty liver or FLHS. Moreover, in the summer season, laying hens frequently suffer from fatty liver or FLHS, especially those reared in conventional battery cages [13-14,22-23] . In addition, other hepatic diseases, such as salmonellosis or inclusion body hepatitis by FAdV-4, could co-occur [24-25] , so careful diagnosis is needed so that other hepatic diseases are not overlooked.…”