Environmental temperature as a factor in the aetiology of fatty liver-haemorrhagic syndrome in the fowl

Abstract

Unidirectional air flow isolators were used to house laying hens at 13 degrees C, 18--30 degrees C and 29 degrees C. Their diet was formulated to provide 2655 k cal metabolisable energy/kg and 142 g crude protein/kg. Groups were killed for examination at the age of 35 and 45 weeks. Sub-clinical FLHS occurred in all isolators but in the case of the younger hens appeared to be more prevalent at 29 degrees C than at 13 degrees C. Both the triglyceride and the glycogen content of the liver were higher at 29 degrees C despite a reduction in food intake. The free fatty acid level in the plasma was lower, probably as a consequence of reduced lipolysis. Liver haemorrhage was associated with an increase in plasma aspartate transaminase activity. It was concluded that an interaction between environmental temperature and the energy balance is not the only factor involved in the aetiology of FLHS and maybe of secondary importance, and that there is a pathogenic relationship between hepatic steatosis and haemorrhage.