The effect of increasing levels of fish oil-containing structured triglycerides on protein metabolism in parenterally fed rats stressed by burn plus endotoxin.
This report investigates the effect of various levels of medium-chain/fish oil structured triglycerides on protein and energy metabolism in hypermetabolic rats. Male Sprague-Dawley rats (192 to 226 g) were continuously infused with isovolemic diets that provided 200 kcal/kg per day and 2 g of amino acid nitrogen per kilogram per day. The percentage of nonnitrogen calories as structured triglyceride was varied: no fat, 5%, 15%, or 30%. A 30% long-chain triglyceride diet was also provided as a control to compare the protein-sparing abilities of these two types of fat. Nitrogen excretion, plasma albumin, plasma triglycerides, and whole-body and liver and muscle protein kinetics were determined after 3 days of feeding. Whole-body protein breakdown, flux, and oxidation were similar in all groups. The 15% structured triglyceride diet maximized whole-body protein synthesis (p < .05). Liver fractional synthetic rate was significantly greater in animals receiving 5% of nonprotein calories as structured triglyceride (p < .05). Muscle fractional synthetic rate was unchanged. Plasma triglycerides were markedly elevated in the 30% structured triglyceride-fed rats. The 30% structured triglyceride diet maintained plasma albumin levels better than those diets containing no fat, 5% medium-chain triglyceride/fish oil structured triglyceride, or 30% long-chain triglycerides. Nitrogen excretion was lower in animals receiving 30% of nonnitrogen calories as a structured triglyceride than in those receiving 30% as long-chain triglycerides, but this difference did not reach statistical significance (p = .1). These data suggest that protein metabolism is optimized when structured triglyceride is provided at relatively low dietary fat intakes.
Gollaher
C J
CJ
Laboratory of Nutrition/Infection, New England Deaconess Hospital, Harvard Medical School, Boston, MA 02215.
Fechner
K
K
Karlstad
M
M
Babayan
V K
VK
Bistrian
B R
BR
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002056:Burns / Q000150:complications* / Q000378:metabolism; D004044:Dietary Proteins / Q000187:drug effects / Q000378:metabolism*; D004731:Endotoxins / Q000633:toxicity*; D004734:Energy Metabolism / Q000187:drug effects; D005395:Fish Oils / Q000737:chemistry / Q000494:pharmacology*; D007930:Leucine / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D010288:Parenteral Nutrition; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000209:etiology* / Q000378:metabolism; D014280:Triglycerides / Q000737:chemistry / Q000494:pharmacology*
D004044:Dietary Proteins; D004731:Endotoxins; D005395:Fish Oils; D014280:Triglycerides; D007930:Leucine; D009584:Nitrogen