Lupinosis of ewes around the time of mating reduces reproductive performance

Abstract

Lupinosis was induced in Merino ewes by subcutaneous injections of phomopsin toxins, given for 2 weeks before and up to 2 weeks after the start of joining, and the reproductive performance of the injected ewes was compared with untreated control ewes. Two experiments were conducted in consecutive years, with similar results. The liver damage and impairment of liver function due to lupinosis were measured by increases in plasma activities of glutamate dehydrogenase and gamma glutamyl transferase, plasma concentration of bilirubin, and plasma clearance of bromosulfthalein. Ovulation rate was depressed by phomopsin administration (1.11 v. 1.33 for the combined phomopsin-treated and control ewes, P < 0.001), and fewer phomopsin-treated ewes were pregnant (70.4% for the combined phomopsin-treated ewes v. 93.8% for the combined control ewes, P < 0.01). Thus, fewer lambs were born to the phomopsin-treated ewes compared with the control ewes (66.0 v. 109.3% for the combined years, P < 0.01). These results indicate that there may be severe detrimental effects of phomopsin intoxication on reproductive performance of ewes.

Scientific Opinion on the risks for animal and public health related to the presence of phomopsins in feed and food

“…Crude extract used by Barnes (1993) and Barnes et al (1996Barnes et al ( , 1997 was derived from the C4274 (Department of Agriculture and Food Culture Collection Number) isolate of D. toxica. One laboratory (CSIRO) primarily used purified, crystalline phomopsin in their studies, while the other (DAFWA) primarily used a crude extract of cultures of D. toxica.…”

“…per day, yet in another experiment 100 % of sheep dosed 50 μg phomopsins/kg b.w. Barnes et al (1996) conducted two experiments to examine the effect of lupinosis around the time of mating on reproductive performance in mature ewes (3.5 to 5.5-years-old). There is evidence, that as in rats with a s.c. dosing route, a single oral dose of phomopsins is less toxic than the same total dose given as multiple, smaller, oral doses.…”

“…In the majority of the studies, both the crystalline phomopsin and the crude extract were sourced from the same isolate of D. toxica (Department of Agriculture and Food Culture Collection Number WA1515, also identified by Commonwealth Mycological Institute Collection Number IMI 153063). Crude extract used by Barnes (1993) and Barnes et al (1996Barnes et al ( , 1997 was derived from the C4274 (Department of Agriculture and Food Culture Collection Number) isolate of D. toxica.…”

“…It is not recorded to what degree liver disease was caused by the feeding of the toxic stubble, but at day 53, ewes being fed the highest rate appeared to have a lower percentage of pregnancy, as assessed by real-time ultrasound. Barnes et al (1996) conducted two experiments to examine the effect of lupinosis around the time of mating on reproductive performance in mature ewes (3.5 to 5.5-years-old). Significant liver disease and deaths due to lupinosis were produced by s.c. injections of a crude extract of D. toxica.…”