JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES SYSTEM
May 2018
S-M18

Signalment (JPC # 2640635):  Salt water, penned Atlantic salmon (Salmo salar), first and second year stock

HISTORY:  Over the course of several months, 6-16% of the stock of 100,000 fish developed lenticular cataracts.  The fish were intensively farmed and maintained on a low grade, producer formulated ration. 

HISTOPATHOLOGIC DESCRIPTION:  Eye, lens:  Multifocally, separating and replacing subcapsular lens fibers are variably sized, irregularly shaped eosinophilic homogeneous to granular globules (morgagnian globules).  Multifocally individual lens epithelial cells deep to the superficial lens epithelium, are markedly hypertrophied with abundant eosinophilic microvacuolated cytoplasm and retained nuclei (bladder cells).Lens epithelium, especially at the poles of the lens, is hyperplastic forming up to 3 cell layers.  At one pole, lens epithelial cells become spindyloid and are separated by fine collagen fibers (fibrous metaplasia).  There are multifocal large lakes of proteinaceous fluid replacing lens fibers (liquefied lens fibers). 

MORPHOLOGIC DIAGNOSIS:  Eye, lens:  Cataractous change, circumferential, moderate to severe, with epithelial hyperplasia, posterior lens epithelial migration,  and fibrous metaplasia, Atlantic salmon (Salmo salar), piscine.

ETIOLOGIC DIAGNOSIS:  Nutritionally induced cataract

GENERAL DISCUSSION: 

PATHOGENESIS: 

TYPICAL CLINICAL AND GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES: 

  1. Barthold SW, Griffey SM, Percy DH.: Pathology of Laboratory Rodents & Rabbits, 4th ed. Ames, IA: Blackwell Publishing Ltd; 2016:4,161,295,318.
  2. Davidson MG, Nelms SR. Diseases of the lens and cataract formation. In: Gelatt KN, ed. Veterinary Ophthalmology. Vol.2 5th ed. Philadelphia, PA : Lippincott Williams & Wilkins; 2013:797-821.
  3. Dubielzig RR, Ketring KL, McLellan GJ, Albert DM. Diseases of the lens. In: Dubielzig RR, Ketring KL, McLellan GJ, Albert DM, eds. Veterinary Ocular Pathology: a comparative review. Philadelphia, PA: Saunders Elsevier; 2010:327-329.
  4. Richter M, Guscetti F, Spiess B. Aldose reductase activity and glucose-related opacities in incubated lenses from dogs and cats. Amer J Vet Res 2002;63(11):1591-97.
  5. Waagbø R, Troße C, Koppe W, Fontanillas R, Breck O. Dietary histidine supplementation prevents cataract development in adult Atlantic salmon, Salmo salar, in seawater. British Journal of Nutrition 2010;104:1460–1470.
  6. Wilcock BP. Special senses. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Saunders Elsevier; 2016:442-444.
  7. Wilcock BP. Eye, Eyelids, Conjunctiva and Orbit. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Mosby; 2012:1209-10.


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