erythrocyte lysis. Vitamin E deficient salmonids are
recognised from gross observations and the examination of
stained tissue sections.
Histological abnormalities associated with pantothenic
acid-deficient fish (vitamin B5) exhibit dermatitis and
exudate-covered gill lamellae, with extensive hyperplasia
(Fig. 10.22). Differential diagnosis include changes
attributed to infestation with Paramoeba perurans (see
Fig. 8.2).
Vitamin B 6 deficiency in rainbow trout includes anorexia,
listlessness, frantic erratic swimming, and ataxia. Deficiency
can be readily determined by measuring pyridoxineenhanced liver aspartate aminotransferase (ASAT) activity
before clinical signs of deficiency are apparent. Histological
Fig. 10.16 X ray showing two different types of spinal deformity in farmed rainbow trout with vitamin C deficiency
Fig. 10.17 Abnormality of the caudal part of the vertebral column in
farmed rainbow trout suffering from vitamin C deficiency
Fig. 10.18 Vitamin C deficiency in rainbow trout. The cartilage of the
lamellae is curved and show irregularities. The cartilage cells are
hydropic and vacuolated. Azan and toluidine blue. Low power
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10 Production Diseases and Other Disorders