PCR Amplification for Detection of Synergistes jonesii, the Ruminal Bacterium that Degrades the Toxins of Leucaena leucocephala

摘要

Large scale ranching requires a reliable continuous supply of livestock forage but due to the poor soil conditions and periods of overall low rainfall experienced in many areas, native grasses in south Texas are not always able to supply the animal'sfeed demands. Leucaena, Leucaena leucocephala, is a highly digestible, high quality forage legume (Jag Jiwan Ram et al., 1994; Aschfalk et al., 2000) that has the potential to be used as forage in mis area due to its drought tolerance, disease resistanceand ability to grow in poor soils (Akingbade et al., 2001). In some areas of south Texas where leucaena has been planted, it thrives, growing up to 10 m within 2 years if not grazed (personal observation). However, leucaena contains mimosine, a toxic non-protein amino acid analogue of tyrosine (Hegarty et al., 1964; Jones, 1985; Hammond, 1995) and under certain conditions has caused poisoning of Texas cattle (Anderson et al., 2001). During mastication and rumen digestion, mimosine undergoes enzymatic degradation to 3-hydroxy-4(1H)-pyridone (3,4-DHP) and its isomer 2,3-dihydroxy pyridine (2,3-DHP), both of which are also toxic (Jones, 1985; Hammond, 1995). Symptoms of leucaena toxicosis include a partial loss of appetite, emaciation, poor live weight gains, alopecia (especially near the tail switch, near the base of the tail and at brand sites), scaly skin, ear and eye lesions, mouth ulceration and drooling viscid saliva (Jag Jiwan Ram et al., 1994).