title: Relationship between thiamine concentration and fermentation patterns in the rumen fluid of dairy cows fed with graded concentrate levels.
abstract: The objective of this study was to investigate the relationship between the thiamine concentration and the fermentation patterns [pH, concentration of short-chain fatty acids (SCFA)] in the free liquid (FRL) and particle-associated liquid (PARL) of the rumen in dairy cows fed with graded concentrate levels in the diet. Four ruminally cannulated Holstein cows in mid lactation were fed [semi-ad libitum, 18 kg dry matter (DM)/day] diets consisting of hay (H) and slowly degradable concentrate (C), offered in five different H:C ratios (% DM basis) in the following sequence: period 1, 30:70; period 2, 40:60; period 3, 50:50; period 4, 60:40 and period 5, 75:25. A negative quadratic relationship was observed between thiamine concentration in FRL and intake of dietary thiamine (R(2) = 0.36), of concentrate (R(2) = 0.38) and of digestible non-fibre carbohydrates (R(2) = 0.37). The thiamine concentration in PARL was higher (p < or = 0.05) compared to FRL. The ruminal thiamine concentration correlated negatively to pH and positively to concentrations of SCFA and propionate in the rumen. R(2) of these relationships varied markedly (0.002 and 0.77), depending on time after feeding and fluid digesta compartment. The higher R(2) were observed at 8 and 11 h after the morning feeding for FRL (R(2) 0.46-0.71) and PARL (R(2) 0.41-0.77), respectively.
authors.affiliation: Institute of Animal Nutrition, The University of Hohenheim, 70599 Stuttgart, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Tafaj
authors.forename: M
authors.initials: M
authors.lastname: Schollenberger
authors.forename: J
authors.initials: J
authors.lastname: Feofilowa
authors.forename: Q
authors.initials: Q
authors.lastname: Zebeli
authors.forename: H
authors.initials: H
authors.lastname: Steingass
authors.forename: W
authors.initials: W
authors.lastname: Drochner
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism; D004063:Digestion; D004305:Dose-Response Relationship, Drug; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005260:Female; D005285:Fermentation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007774:Lactation / Q000378:metabolism; D019518:Postprandial Period; D011897:Random Allocation; D012417:Rumen / Q000737:chemistry / Q000378:metabolism*; D013831:Thiamine / Q000008:administration & dosage* / Q000378:metabolism; D013997:Time Factors
chemical_list: D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D013831:Thiamine