Nutritional secondary hyperparathyroidism and fibrous osteodystrophy in a Captive African Penguin (Spheniscus demersus) similar to osteomalacia in poultry

A nine-year-old female Black-footed African penguin ( Spheniscus demersus ) was presented for necropsy after a history of reproductive abnormalities, paresis of limbs, weakness and sudden death. Post-mortem examination revealed soft keel, collapsed rib cage with beading of the ribs and bilateral parathyroid enlargement. Classical histological lesions of fibrous osteodystrophy with osteomalacia were observed in the ribs, vertebrae and to a lesser extent femur and tibiotarsus associated with hyperplasia of parathyroid glands. This represents the first report of nutritional secondary hyperparathyroidism in birds of the order Spheniciformes , most likely caused by low level of calcium supplementation during egg laying. The reproductive abnormalities observed in this penguin and others from the same group (asynchronous egg laying cycles, abnormal breeding behavior) were most likely exacerbated by the lack of an adequate photoperiod mimicking the natural daylight pattern.