title: The effect of the rate and route of nutrient delivery on total body and organ composition in rats.
abstract: To assess the effects of administering increasing rates of total parenteral nutrition (TPN) on total-body and organ composition, infusion catheters were implanted aseptically into the right jugular vein of Sprague-Dawley rats. Animals received 14 d of either a high (H), medium (M), or low (L) rate of TPN infusion (1.22, 1.49, 1.74 MJ.kg-1BW.d-1 and 1.74, 1.48, 1.22 gN.kg-1BW.d-1, respectively: 1:1 lipid:glucose energy), or the TPN solution orally (O TPN group). Weight-matched (w) chow-fed (c) animals were sacrificed at the same final weight as the L TPN and O TPN groups (190 g, LWC group), or the M and H TPN groups (250 g, HWC group). There were 5 animals in each group. The rates of body weight increase of the M TPN, H TPN, and HWC groups were similar (p > 0.05) and greater than the L TPN and O TPN groups (p < 0.001). The L TPN and O TPN groups who received similar amounts of nutrients had similar rates of weight gain. Total body lipid expressed as a percentage of body weight was significantly greater (P < 0.01) in the L, M, and H TPN groups compared to the orally fed groups. The proportion of water and protein in the fat-free wet weight were similar for all groups (p > 0.05). The lipid content of the liver as a percentage of its weight was greater (P < 0.05) in the orally fed groups. There was no significant difference in the percentage of water or protein of individual organs or the total viscera between any group. These finding indicate that: (a) TPN administration can maintain similar rates of protein and water deposition compared to normal growth-maintaining oral diets; (b) there is an effect of route of TPN administration on lipid deposition in adipose tissues; and (c) infusion of a glucose/lipid TPN regimen at rates in excess of requirements for growth in rats promotes lipid deposition in adipose tissues rather than visceral tissues.
authors.affiliation: University of Sydney, Department of Surgery, Royal North Shore Hospital, NSW, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Kee
authors.forename: R C
authors.initials: RC
authors.lastname: Smith
mesh_terms: D000818:Animals; D001823:Body Composition; D001834:Body Water; D001835:Body Weight; D003106:Colon / Q000737:chemistry; D002149:Energy Intake; D007668:Kidney / Q000737:chemistry; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000737:chemistry; D008297:Male; D010179:Pancreas / Q000737:chemistry; D010289:Parenteral Nutrition, Total / Q000379:methods*; D011506:Proteins / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000737:chemistry; D014781:Viscera / Q000737:chemistry; D015430:Weight Gain
chemical_list: D008055:Lipids; D011506:Proteins