title: Evidence of In Vivo Absorption of Lactate and Modulation of Short Chain Fatty Acid Absorption from the Reticulorumen of Non-Lactating Cattle Fed High Concentrate Diets.
abstract: Short-chain fatty acids (SCFAs) and lactate are endproducts of rumen fermentation and important energy sources for the host ruminant. Because their rapid accumulation results in ruminal acidosis, enhancement of the absorption of SCFA and lactate across reticuloruminal wall is instrumental in increasing energy supply and preventing ruminal acidosis in cattle. This study investigated whether the reticuloruminal absorption of SCFAs and lactate was altered by different strategies of high concentrate feeding. Eight rumen-cannulated, non-lactating Holstein cows were fed a forage-only diet (baseline) and then gradually adapted over 6 d to a 60% concentrate level. Thereafter, this concentrate-rich diet was fed for 4 wk either continuously (Con; n = 8) or interruptedly (Int; n = 8). Absorption of SCFAs and lactate was determined in vivo from the experimental buffer introduced into the washed reticulorumen. The buffer contained acetate, propionate, butyrate and lactate at a concentration of 60, 30, 10 and 5 mmol/L, respectively and Cr-EDTA as a marker for correcting ruminal water fluxes. The reticuloruminal absorption after 35 and 65 min of buffer incubation was measured at the baseline, after 1 wk of 60% concentrate feeding in the interrupted model (Int-1) and after 4 wk of concentrate feeding in both feeding models (Int-4 and Con-4). Data showed that the absorption rates of individual and total SCFAs during the first 35 min of incubation of Con-4 were highest (~1.7 times compared to baseline), while Int-1 and Int-4 were similar to respective baseline. Lactate was not absorbed during forage-only baseline and 1-wk concentrate feeding, but after 4-wk feeding of concentrates in both models. In conclusion, SCFAs absorption across the reticulorumen of non-lactating cattle was enhanced by the 4-wk continuous concentrate feeding, which seems to be more advantageous in terms of rumen acidosis prevention compared to the interrupted feeding model. The study provides evidence of lactate absorption across the reticulorumen of non-lactating cattle after both continuous and interrupted 4-wk concentrate feeding.
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Qumar
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Ratchaneewan
authors.initials: R
authors.lastname: Khiaosa-Ard
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Poulad
authors.initials: P
authors.lastname: Pourazad
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.|Institute for Milk Hygiene, Milk Technology and Food Science, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Stefanie U
authors.initials: SU
authors.lastname: Wetzels
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Fenja
authors.initials: F
authors.lastname: Klevenhusen
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology, IFA-Tulln, University of Natural Resources and Life Sciences in Vienna, Tulln, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kandler
authors.affiliation: Institute of Veterinary Physiology, Free University of Berlin, Berlin, Germany.
authors.forename: Jörg R
authors.initials: JR
authors.lastname: Aschenbach
authors.affiliation: Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Qendrim
authors.initials: Q
authors.lastname: Zebeli
mesh_terms: D000138:Acidosis / Q000378:metabolism; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology; D000818:Animals; D002417:Cattle; D018592:Cross-Over Studies; D004032:Diet; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D007774:Lactation / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism*
chemical_list: D005232:Fatty Acids, Volatile; D019344:Lactic Acid