title: Emulsification and fatty acid chain length affect the kinetics of [14C]-medium-chain triacylglycerol utilization by neonatal piglets.
abstract: In vivo oxidation kinetics of medium-chain triglycerides (MCT) composed of [1-14C]hexanoate (tri-6:0) or [1-14C]octanoate (tri-8:0) were compared after being fed to day-old piglets (1.4 kg; n = 4/treatment). Animals were fitted with arterial and oro-gastric catheters and placed into respiration chambers held at 35 degrees C. The radiolabeled MCT were fed in equimolar amounts (6.5 mmol/kg0.75), in either nonemulsified form or as 30% (v/v) emulsions, using polyoxyethylene sorbitan monooleate as an emulsifier. Expired CO2 was quantified and specific radioactivity (Bq/mumol) determined at 20-min intervals over 24 h, and serial blood samples were drawn for measurement of plasma hexanoate and octanoate by HPLC. The rate [mumol/(h.kg0.75)] and extent (mmol/kg0.75) of MCT oxidative utilization (i.e., composite of digestion, absorption and oxidation) were calculated from the kinetics of 14CO2 expiration. Emulsification increased both the rate and extent of MCT oxidative utilization by > 20% regardless of fatty acid chain length (P < 0.05). Maximal MCT oxidation rates occurred at 3.5 h after feeding and were sufficient to meet up to 48% of the piglets' energy expenditure. The maximal rate of tri-6:0 oxidative utilization exceeded that of tri-8:0 by 37% (P < 0.05), but the extent of utilization was not affected by fatty acid chain length. Plasma medium-chain fatty acid concentrations were in agreement with these observations, being higher in pigs fed emulsified MCT than in pigs fed nonemulsified MCT (P < 0.05) and being higher in pigs fed tri-6:0 than in animals fed tri-8:0 (P < 0.05). Collectively, these data demonstrate that newborn piglets can effectively digest, absorb and oxidize MCT, that utilization is improved with emulsification, and that tri-6:0 is utilized more rapidly than tri-8:0.
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana 61801.
authors.forename: J
authors.initials: J
authors.lastname: Odle
authors.forename: X
authors.initials: X
authors.lastname: Lin
authors.forename: T M
authors.initials: TM
authors.lastname: Wieland
authors.forename: T A
authors.initials: TA
authors.lastname: van Kempen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001944:Breath Tests; D002208:Caproates / Q000097:blood; D002210:Caprylates / Q000097:blood; D002245:Carbon Dioxide / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D004750:Enteral Nutrition / Q000662:veterinary; D005227:Fatty Acids / Q000097:blood / Q000737:chemistry*; D010084:Oxidation-Reduction; D013552:Swine / Q000378:metabolism*; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D002208:Caproates; D002210:Caprylates; D004655:Emulsions; D005227:Fatty Acids; D014280:Triglycerides; D002245:Carbon Dioxide; C037652:hexanoic acid; C031492:octanoic acid