Fatty liver haemorrhagic syndrome
This is a problem of mature laying birds characterized by fatty liver, mortalities and drop in egg production. In contrast to mammals where lipogenesis is in adipose tissues, it occurs in the liver in birds. As birds approach sexual maturity and lay, there is further increase in liver lipogenesis. It is this lipogenic liver function that forms the key stone for occurrence of condition involving excess accumulation of liver fat.Aetiology
It is caused by too much amount of caloric dense which is high carbohydrate and low fat resulting in obesity especially in absence of lipotrophic nutritional factors like choline and inositol.
High temperature and lack of exercise like in caged layers.
Housing and environmental problem which predispose birds to excessive heat and poor ventilation can be the cause.
Increased lipogenesis resulting from abnormal estrogen and thyroxine levels in blood can be the cause.
Some bird strains vary in amount of lipid or fat in which they contain in liver (25%-50%) depending on bird strain.
Clinical manifestation and effects of the disease
There are mortalities in actively laying birds.
Accelerated weight gain can be observed.
There is drop in flock egg production and egg bounding. Egg bounding is the blockage of oviduct by egg due to narrowing of lumen by fat.
Post-mortem findings
There is enlarged putty-like and friable liver which may contain up to 70% fat. The liver may show multiple haemorrhagic foci or hematoma or actual liver rupture with the presence of blood clot in peritoneum. There may be excessive fat deposit in abdominal wall which may attain 2-3cm in thickness. There is excessive perigastric and pericardial fat. There is egg bounding of fully formed eggs in oviduct.
Control
Control should be targeted as at alleviating as many are the causative factors as possible including:
Reduction in caloric intake during hot season, introduction of some additional fibre or use of more fibre raw materials, environmental control of heat stress through improved ventilation and supplementation with lipotrophic factor for example, addition of yeast in feed.
Fatty liver kidney syndrome/pink liver disease
This is a metabolic disorder of young broilers and sometimes pullets commonly 10-30 days of age characterized by extensive fatty infiltration of body tissue with enlarged liver, kidneys and heart. It arises from a failure of hepatic gluconeogenesis due to marginal deficiency in biotin.Aetiology
The condition involves interaction of nutritional, environmental stress and maternal factors such as marginal deficiency of dietary biotin and combination of fat and protein.
High levels of fat offer protection by depressing the need for lipogenesis making more biotin available for gluconeogenesis or pyruvate carboxylase.
Floor rearing makes fecal biotin available.
Starvation and stress which deplete the glycogen reserve can cause the condition.
Age and biotin status of the parent bird, other diseases which cause stress and depress intestinal absorption are also factors to consider.
Clinical signs
The signs are of sudden onset with affected birds depressed and recumbent. Mortality is between 5-20%
Post-mortem lesions
There is enlarged pale fat infiltrated liver and kidneys.
Pink adipose tissue and subcutaneous fat and blackish fluid in intestine and crop can be observed.
The parlour of liver and kidneys is due to excess amount of fat which is about 2-5 times the normal. Fatty infiltration is widespread but less marked in other times including cardiac and skeletal muscles and central nervous system.
Control
Alleviating as much as connective factor as possible can help in the control of this condition.