ORIGINAL RESEARCH A comparative study on mimosine, 3,4-dihydroxy pyridone (3,4-DHP) and 2,3-dihydroxy pyridone (2,3-DHP), purine derivatives (PD) excretion in the urine, thyroid hormone and blood metabolites profiles of Thai swamp buffalo (Bubalus bubalis) and Murrah buffalo (Bubalus bubalis) Thongsuk Jetana & Sirima Thongruay & Sawong Uswang & Runchuan Hengtrakulsin Accepted: 8 September 2011 /Published online: 18 September 2011 # Springer Science+Business Media B.V. 2011 Abstract Four Thai swamp buffaloes (SB) and four Murrah buffaloes (MB) fed a based diet of fresh ruzi grass (Bachiaria ruziziensis) with an increased proportion of fresh leucaena leaves. Intake of nutrients in animals increased when ruzi grass was mixed with leucaena. Digestibility of nutrients were the highest in SB and MB fed diets containing 25% and 50% of leucaena, respectively, and nitrogen (N) balances in both animal breeds were varied among diets. The regression equation coefficient of mimosine + DHP in the urine was twice as high in SB than in MB. Urinary purine derivatives excretion rate in SB was higher than that in MB. Plasma triiodothyronine and thyroxine declined in both animal breeds fed a diet containing >1 g mimosine intake/kg BW 0.75 /day. Plasma urea–N was the lowest in SB, but the highest in MB when fed a diet containing 84% of leucaena. Plasma β-HBA in SB have declined when diets contained >50% of leucaena but that in MB was not affected by any diet. In conclusion, the effect of leucaena in diet upon buffalo breeds depends on the proportion of leucaena in the diet, mimosine contents and condensed tannins components. Keywords Buffalo . Dihydroxypyridone (DHP) . Leucaena (Leucaena leucocephala) . Mimosine . Purine derivatives . Ruzi grass (Bachiaria ruziziensis) Abbreviations ADF Acid detergent fibre ADL Acid detergent lignin BW Body weight BW 0.75 Metabolic body weight CT Condensed tannins DHP Dihydroxy pyridone DM Dry matter DMI Dry matter intake DOMI Digestible organic matter intake GE Gross energy MB Murrah buffalo MJ Mega joules N Nitrogen NDF Neutral detergent fibre NDFI Neutral detergent fibre intake OM Organic matter OMI Organic matter intake PD Purine derivative PUN Plasma urea nitrogen RDP Rumen degradable protein rpm Revolutions per minute SB Swamp buffalo SEM Standard error of mean T 3 Triiodothyronine T 4 Thyroxine β-HBA Beta-hydroxybutyrate T. Jetana (*) : S. Thongruay : S. Uswang Research and Development Center for Livestock Production Technology, Faculty of Veterinary Science, Chulalongkorn University, Henri Dunant Street, Phathumwan, Bangkok 10330, Thailand e-mail: Thongsuk.J@Chula.ac.th R. Hengtrakulsin Murrah Farm, 99/14 Moo 12, Nong Maikaen, Amphoe Plaengyao, Chachoengsao 24190, Thailand Trop Anim Health Prod (2012) 44:887–897 DOI 10.1007/s11250-011-9983-1