Achromatosis

Introduction

Achromatosis aka the failure to lay down normal feather pigments is caused by a variety of nutritional deficiencies including choline, lysine and riboflavin deficiencies.

Signalment

Achromatosis is caused by a lysine deficiency in dark breeds of chickens, turkeys and quail. It is also caused by a riboflavin or choline deficiency in growing cockatiels. Once rapid growth is complete in these birds, moulting occurs and when feathers regrow they are of a normal pigment.

Achromatosis is important as it indicates a significant underlying nutritional deficiency, however the level of pigmentation does not reflect the severity of the deficiency. Only in extreme cases do the feathers not grow at all.

Diagnosis

Diagnosis of achromatosis is possible on physical exam, however this should initiate an investigation into potential nutritional deficiencies.

Treatment

Treatment should be supplement with the limiting nutrient. Response to clinical signs should be observed in growing birds, with growing feathers demonstrating normal pigment. Once the rapid growth phase is complete, the nutrient requirements of the bird is reduced. Therefore it may be possible to return to the diet that was originally nutrient-deficient. If the condition is diagnosed at the end of the growth phase then treatment is not normally necessary.

Prognosis

Prognosis is good if the underlying nutritional deficiency is addressed, or the rapid growth phase ends (reducing the nutritional requirements of the bird). The birds will moult and grow normal feathers.

References

Forbes NA & Altman RB (1998) Self-Assessment Colour Review Avian Medicine Manson Publishing Ltd