Vitamin C Deficiency - Fish

Also known as: Ascorbic Acid Deficiency — Hypovitaminosis C

Introduction

Most animals can synthesis vitamin C in sufficient quantities for normal growth and function, but many fish cannot, as they lack the enzyme L-gulonolactone oxidase for synthesis of vitamin C from glucose.

Vitamin C is a cofactor for hydroxylation of proline to hydroxyproline, an essential component of collagen, and thus it is necessary for the formation of connective tissues, scar tissue in wound repair and bone matrix.

Vitamin C also facilitates the absorption of iron. It can spare vitamin E in reducing peroxidation of lipids in fish tissues, and is essential for the regeneration of vitamin E after oxidation.

It is necessary for a maximum rate of immune responses and enables a good response to stressors.

Fish show signs if they are fed diets deficient in vitamin C. Most commercial feed ingredients are almost completed devoid of vitamin C and it has to be supplemented. However vitamin C is very sensitive to oxidative destruction during processing and storage and that a significant amount is lost at that time.

Clinical Signs

The most common signs observed with vitamin C deficiency are skeletal deformities seen as: spinal lordosis and scoliosis, stress fractures and opercular and gill lamellar deformation.

This may appear to the owner as a slight asymmetry at the level of the spine.

Fish may otherwise be normal, or may show external and internal haemorrhaging, usually preceded by anorexia and lethargy.

Wound healing may also progress at a reduced rate.

Diagnosis

Radiography is useful in identifying any spinal deformities, however these may have arisen through trauma or inheritance.

Reliable measures of vitamin C deficiency include:

Low liver and kidney concentrations

Vertebral collagen level, especially in channel catfish and rainbow trout

Treatment

Treatment involves vitamin C supplementation.

Care should be taken to take into account the oxidation that can occur during feed processing and storage.

More stable derivatives of vitamin C have been developed to counteract these problems by conjugating ascorbic acid with phosphate or sulfate.

Fish are more prone to developing bacterial infections, and any problems should be dealt with promptly.

Vitamin C Deficiency - Fish Learning Resources
Flashcards Test your knowledge using flashcard type questions	Ornamental Fish Q&A 23

References

National Research Council,Committee on the Nutrient Requirements of Fish and Shrimp (2011) Nutrient Requirements of Fish and Shrimp National Academic Press

Lovell, T. (1998) Nutrition and Feeding of Fish Springer

Roberts, R. (2001) Fish Pathology Elsevier Health Sciences

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