Physiological effects of endophyte-infected perennial ryegrass straw on female camels in the Middle East

Abstract

Recently, the United Arab Emirates has increased importation of perennial ryegrass (Lolium perenne) straw as part of the grass/hay ration for camels. Unfortunately, perennial ryegrass straw may be infected with the endophyte Neotyphodium lolii which produces lolitrem B, a toxic alkaloid responsible for the disease 'ryegrass staggers.' A range-finding study was conducted using 24 non-pregnant female camels fed four doses (0, 1111, 1478 and 2273 ppb) of lolitrem B-containing perennial ryegrass straw over 56 days to establish a threshold of toxicity in camels so that perennial ryegrass straw can be safely fed as part of their dietary ration. Physiological parameters were evaluated. Neurological deficits were evaluated by videotape and scored according to an established scale for the neurological syndrome ryegrass staggers. Camels in the endophyte-infected groups developed varying degrees of ataxia. Brain edema, degenerative renal and hepatic lesions as well as Purkinje cell vacuolar degeneration were observed in camels receiving the highest dose. To avoid clinical disease in camels, endophyte-infected perennial ryegrass straw should be fed at 500 ppb or lower lolitrem B; straw at 1000 ppb or higher should be diluted to achieve the 500 ppb threshold of toxicity.

Activities and Effects of Ergot Alkaloids on Livestock Physiology and Production

“…The geographic scope of this impact ranges from countries such as the United States [ 1 ], New Zealand [ 2 ], and Australia [ 3 ] that have a heavy reliance on grazing for aspects of livestock production. This impact also extends to countries such as Japan [ 4 , 5 ], Korea [ 6 ], and the United Arab Emirates [ 7 ] that import hay as a feedstuff for livestock production and maintenance and countries such as Australia that use ergot-contaminated feeds in intensive livestock production settings [ 8 , 9 ]. A substantial challenge in the elucidation of ergot alkaloid-induced effects is the highly variable individual animal response to exposure.…”

The Role of the Oregon State University Endophyte Service Laboratory in Diagnosing Clinical Cases of Endophyte Toxicoses

“…Analytical methods using HPLC-fluorescence were developed and refined for testing feed material. − However, threshold levels of toxicity were needed to correlate alkaloid levels in feed with clinical disease so that preventative “safe feed” practices could be instituted in livestock management. A series of studies determined the threshold levels for both the ergot alkaloid ergovaline, 1 (Figure ), in tall fescue (Festuca arundinacea), and the perennial ryegrass (Lolium perenne) toxicant causing ryegrass staggers, lolitrem B, 2 (Figure ), in various animals. − …”

“…As a consequence, they have begun importing the majority of their livestock feed as opposed to growing it domestically. New threshold levels of toxicity need to be established for native livestock species consuming tall fescue and perennial ryegrass straw, with particular attention paid to replicating the environmental conditions in which these animals exist; such a study has been conducted for camelids …”

Recent investigations of ergot alkaloids incorporated into plant and/or animal systems

“…The result has been increased occurrences of ergot alkaloid issues arising in areas not typically associated with pasture-based agriculture. To illustrate, weight loss in camels in the United Arab Emirates consuming an imported ergovaline-containing endophyte-infected perennial ryegrass straw (Alabdouli et al, 2014 ) along with issues associated with import and feeding of perennial ryegrass straw to Japanese black cattle (Miyazaki et al, 2001 ) have been documented. In addition to these incidents, grasses can also become infested with Claviceps purpurea where the alkaloids, typically ergotamine and ergocristine, are responsible for the resultant ergotism associated with C. purpurea .…”