Increased anaplerosis of the tricarboxylic acid cycle decreased meal size and energy intake of cows in the postpartum period.
The objective of this study was to determine the effects of anaplerosis of the tricarboxylic acid cycle on feeding behavior and energy intake of cows in the postpartum period. We infused propionic acid (PA) and glycerol (GL) continuously into the abomasum and hypothesized that PA will decrease meal size and energy intake compared with GL because PA enters the tricarboxylic acid cycle, likely stimulating oxidation of acetyl CoA and satiety compared with GL. Three experiments (Exp.) were conducted using 20 Holstein cows between 3 and 22 d postpartum (8 cows in Exp. 1 and 6 cows each for Exp. 2 and 3). Treatments were compared using isoenergetic (Exp. 1, 193 kcal/h) and isomolar (Exp. 2, ∼0.5 mol/h) continuous infusions of PA (99.5%) and GL (99.7%) to the abomasum using a double crossover design with four 2-d infusion periods each, and 2 mol of PA or GL pulse-dosed to the abomasum using a crossover design (Exp. 3). Treatment sequences were assigned alternately to cows based upon date of parturition. Feeding behavior was recorded by a computerized data acquisition system for Exp. 1 and 2. Propionic acid decreased dry matter intake (DMI) compared with GL 16.7 and 23.4% in Exp. 1 and 2, respectively. The decrease in DMI was because PA decreased meal size compared with GL by 12.6 and 15.3% in Exp. 1 and 2, respectively. Propionic acid decreased total metabolizable energy intake (diet plus treatment infusions) compared with GL for both experiments. Compared with PA, GL increased plasma glucose and insulin concentrations for Exp. 2 only. In Exp. 3, PA decreased hepatic acetyl CoA content 34%, whereas GL increased hepatic acetyl CoA content 32%, resulting in lower hepatic acetyl CoA content for PA compared with GL at 30 min (18.0 vs. 36.9 nmol/g), which persisted at 60 min after dosing (21.9 vs. 32.8 nmol/g). Consistent with our hypothesis, the obligatory anaplerotic metabolite PA decreased meal size, DMI, and total metabolizable energy intake compared with GL, likely because of differences in their hepatic metabolism.
Department of Animal Science, Michigan State University, East Lansing 48824.
Laura B
LB
Gualdrón-Duarte
Department of Animal Science, Michigan State University, East Lansing 48824. Electronic address: allenm@msu.edu.
Michael S
MS
Allen
D000018:Abomasum / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle; D002952:Citric Acid Cycle / Q000502:physiology*; D018592:Cross-Over Studies; D004435:Eating; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005990:Glycerol / Q000008:administration & dosage / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D007774:Lactation; D008099:Liver / Q000201:enzymology; D049590:Postpartum Period; D011247:Pregnancy; D011422:Propionates / Q000008:administration & dosage / Q000378:metabolism*; D012527:Satiation / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin; D011422:Propionates; D000105:Acetyl Coenzyme A; C029658:propionic acid; D005990:Glycerol
acetyl CoA; anaplerosis; control of feed intake; hepatic oxidation theory