Lupinosis

Lupinosis is a mycotoxicosis caused by the ingestion of toxins produced by the fungus Diaporthe toxica (Phomopsis leptostromiformis) which grows on lupin plants.  Allen and Randall 1993 found that in addition to being an hepatotoxicity, lupinosis also resulted in injury to muscle, kidney and adrenal cortex. [1]

Isolation of phomopsin the poison of lupinosis [2]
Lupinosis was first recognised in Germany in 1872 and is being reported in the United States of America, Poland, New Zealand, Australia and South Africa. Sheep are particularly susceptible and cause high economic losses. Two metabolites of P. leptostromijormis (phomopsins A and B) have been isolated as a crystalline mixture from a culture of the fungus on lupin seed. The mixture has been shown to be capable of inducing lupinosis in sheep and in young rats.

Varieties of lupin  [3]
Lupinus angustifolius breeding has been by far the major focus in Australia. Lupinus albus and Lupinus luteus have received more attention in Europe and the former USSR but breeding of Lupinus angustifolius is increasing. The most important disease of the narrow-leaf lupin (Lupinus angustifolius) in Victoria is brown leaf spot which is caused by the fungus Pleiochaeta setosa.

Albus lupin variety Kiev [4]
The management of sheep grazing Albus lupin (Lupinus albus) stubble is similar to those grazing narrow leafed lupins. However, the seed is almost three times bigger and consequently sheep select and eat the seed much more quickly.  Albus have a higher protein and energy content than narrow leafed lupins. In addition, Albus varieties such as Kiev are less prone to Phomopsis infection than narrow leafed lupins.

Lupin stubble paddocks provide a valuable feed source. Careful management reduces the risk of lupinosis which can cause deaths, reduced twining and conception rates at joining, weight loss, poor wool growth and pregnancy toxaemia.

An outbreak of natural lupinosis in lambs in Caceres, Spain was described by Soler Rodrigues et al. in 1991. [5]

Lupinosis is a result of livestock grazing lupin stems or lupin seed infected by the fungus Diaporthe toxica, formerly known as  Phomopsis leptostromiformis. New lupin varieties have some resistance to the fungus, however,  danger still remains as favourable conditions are likely to result in the fungus being present in all varieties.

The Western Australian Department of Agriculture and Food recommends to ensure  there is other more digestible feed available and stocking rates are below 15 sheep per hectare to reduce grazing pressure. This reduces the need for sheep to graze lupin stems.
Livestock are removed of the pasture when the grain falls below four grains per ten square centimetres and before the green weeds run out, as lupin stubbles on their own provide poor nutrition and the risk of Lupinosis greatly increases as the animals are more likely to graze the stems.  [6]

Weather [4]
Temperature, rainfall, humidity and dew all influence the production of toxin by the fungus. Rainfall, high humidity or consistent dews when daily maximum temperatures are about 25°C create ideal conditions for toxin production in stubble. Lupinosis most commonly occurs in the first few days following more than 10 mm of summer rain.

[1] Allen JG, Randall AG: The clinical biochemistry of experimentally produced lupinosis in the sheep. Aust Vet J. 1993 Aug;70(8):283-8.
http://www.ncbi.nlm.nih.gov/pubmed/8216093

[2] Culvenor CC, Beck AB, Clarke M, Cockrum PA, Edgar JA, Frahn JL, Jago MV, Lanigan GW, Payne AL, Peterson JE, Petterson DS, Smith LW, White RR: Isolation of toxic metabolites of Phomopsis leptostromiformis responsible for lupinosis. Aust J Biol Sci. 1977 Aug;30(4):269-77.
http://www.publish.csiro.au/?act=view_file&file_id=BI9770269.pdf

[3] Lupins.org: Information Resource Portal for Lupins
http://www.lupins.org/production/

[4] 13 Lupinosis
http://www.agric.wa.gov.au/OBJTWR/imported_assets/content/fcp/lp/lup/lupins/Lupinbulletinch13.pdf

[5] Soler Rodriguez F, Miguez Santiyan MP, Pedrera Zamorano JD, Roncero Cordero V: An outbreak of lupinosis in sheep. Vet Hum Toxicol. 1991 Oct;33(5):492-4.
http://www.ncbi.nlm.nih.gov/pubmed/1746145

[6] Lupinosis is a risk to stock. The Rural 03 Feb, 2011
http://www.therural.com.au/news/local/news/general/lupinosis-is-a-risk-to-stock/2066118.aspx