Influence of gradual adaptation of cattle to Leucaena leucocephala leaf meal on biodegradation of mimosine and 3- hydroxy-4(1H)-pyridone (3,4 DHP) in rumen,their levels in blood,fate and influence of absorbed DHP on thyroid hormones and liver enzymes |
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| Institution: | 1. i3S — Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal;2. Cancer Drug Resistance Group, IPATIMUP — Institute of Molecular Pathology and Immunology of the University of Porto, 4200-465 Porto, Portugal;3. ICBAS-UP — Institute of Biomedical Sciences Abel Salazar, University of Porto, 4099-003 Porto, Portugal;4. NICB — National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland, UK;5. Department of Biological Sciences, FFUP — Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal;6. Department of Pathology and Oncology, FMUP — Faculty of Medicine of the University of Porto, 4200-319 Porto, Portugal;1. DAI-Labor, Technische Universität Berlin, Germany;2. German Turkish Advanced Research Laboratory (GT-ARC), Germany;1. Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, CA, USA;2. Shiley Center for Orthopaedic Research & Education at Scripps Clinic, La Jolla, CA, USA |
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| Abstract: | Three rumen fistulated Karan Fries crossbred (Holstein X Tharparkar) calves were fed increasing dry matter (DM) levels of 25%, 50%, 75% and 100% through leucaena leaf meal (LLM) starting at week 1, 2, 3 and 4, respectively. The mimosine, 3,4 DHP and 2,3 DHP levels were determined in strained rumen liquor (SRL) and serum at 0, 1, 2, 4, 8, 12 and 24 h postfeeding on days 1, 8, 15, 22, 29 and 42. LLM was incubated for 24 h with SRL in vitro on days 0, 7, 14, 21, 28 and 41 to study mimosine and dihydroxypyridone (DHP) biodegradation. On day 43, 1–1.5 l of rumen liquor was transferred to another set of three unadapted calves which were fed 50% LLM after transfer of inoculum. DM intake was 1.78%, 2.13%, 2.27%, 1.66%, 1.54% and 1.35% of live weight during the 1st through 5th week, respectively. Both in vitro and in vivo studies showed extensive degradation of mimosine to 3,4 DHP and 2,3 DHP from first day of LLM feeding. The overall in vitro DHP degradation was nil, 28.6%, 43.3% and 40.1% on day upto 15, 21, 28 and 42 of LLM feeding. No mimosine was found in serum on any day of sampling. The 3,4 DHP detected (56.94±31.65 μg ml−1 serum) one hour post feeding on day 1 exhibited a decline from day 22 onwards. The serum also contained 2,3 DHP on days 8, 15, 22, 42. The faecal and urinary excretion of 3,4 DHP and 2,3 DHP as percent of mimosine intake declined from first week (76.3±2.8) to 4th week (42.1±4.1). The feeding of LLM resulted in reduced level of T3 and T4 within a week of LLM feeding. The level of T3 improved to normal by 6th week while that of T4 remained low. The SGOT and SGPT activities were within normal range. The gradual adaptation to LLM feeding caused Karan Fries calves to acquire DHP degrading ability to nontoxic compounds and this ability was transferred through transfer of rumen liquor from such calves to other unadapted calves at as early as 9th day of LLM feeding. The results revealed the possibility of two types of microbes degrading mimosine and 3,4 DHP to 2,3 DHP. One type of 2,3 DHP degrading microbes may be inhibited in the presence of 3,4 DHP whereas the other type may be active. |
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