Bulletin No 4168 - Plants in Australia which when eaten produce photosensitization in livestock

Authors

T E H Aplin, Western Australian Department of Agriculture

Files

Publication Date

1990

Series Number

4168

Abstract

Photosensitization is the term used to describe inflammation of the skin (usually unpigmented) caused by photodynamic compounds, circulating in blood stream, becoming bound to dermal cells and fluorescing when the animal is exposed to ultraviolet light (290-400 nm).

Photosensitization usually occurs when an animal eats certain plants that contain photodynamic compounds. These compounds can be deposited unchanged in the skin after ingestion, the normal liver being incapable of excreting the native fluorescent compound. This is termed type 1 photosensitization and the compounds involved are naphthodianthrone derivatives. Photodynamic compounds can also be produced through aberrant metabolism by the liver due to a genetic deficiency of specific metabolic enzymes. This is termed type 2 photosensitization.

The most common type of photosensitization is hepatogeneous ( type 3) photosensitization. This occurs when a functionally damaged liver fails to excrete a photodynamic metabolite of green feed. All plants contain chlorophyll in their leaves and when ingested by a herbivore this compound is converted to phylloerythrin by the action of microbes in the gastrointestinal tract. Phylloerythrin, a photodynamic compound, is usually excreted in the bile by the normal liver. However, any pathological process that interferes with the excretion of bile by the liver for more than a few days is likely to result in a build-up of phylloerythrin in the blood stream and photosensitization of the unpigmented skin of the animal.

Number of Pages

20

Publisher

Western Australian Department of Agriculture

City

Perth

Keywords

Plants, Livestock, Photosensitization, Western Australia

Disciplines

Agricultural Science | Animal Sciences | Environmental Indicators and Impact Assessment | Environmental Monitoring | Plant Biology | Plant Sciences

Comments

Bulletin 4168 replaces Bulletin 3960

Recommended Citation

Aplin, T E. (1990), Bulletin No 4168 - Plants in Australia which when eaten produce photosensitization in livestock. Western Australian Department of Agriculture, Perth. Bulletin 4168.
https://library.dpird.wa.gov.au/bulletins/312

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