Fish oil feeding is associated with an increased accumulation of dietary lipids in enterocytes: results from an in vivo study in rats.
BACKGROUND
Chronic fish oil consumption is associated with reduced postprandial lipaemia, but the mechanism behind this effect is not fully understood. We studied whether lipid absorption might be altered in rats fed fish oil.


METHODS
Male Wistar rats were fed fish oil enriched chow (n = 6) or control oil enriched chow (n = 6). After 4 weeks, 61 mg 3H-triolein was instilled into duodenal tied-off loops. Intestinal segments were removed after 15, 30, 45, 60 and 90 min. Enterocytes were then isolated by calcium chelation and quantified by DNA determination. Non-absorbed 3H-lipid and 3H-lipid contents of enterocytes were determined by liquid scintillation counting. Two other groups of rats (2 x 6) fed the experimental diets were given an oral fat load and fasting and postprandial blood samples were taken.


RESULTS
The accumulation of 3H-lipids in enterocytes was higher in rats fed fish oil than in controls (area under the 3H-lipid time curve: 1041.3 versus 670.3 nmol oleic acid x min/microg DNA, P < 0.05). Separation of lipids showed that an accumulation of triglycerides and free fatty acids occurred in rats fed fish oil. The amount of non-absorbed 3H-lipid tended to be higher in the fish oil fed rats (P > 0.1). It was confirmed that the fish oil enriched chow caused lower postprandial lipaemia (34% reduction in serum triglyceride concentrations, P < 0.05).


CONCLUSIONS
Attenuated postprandial lipaemia following fish oil feeding is explained, at least partly, by a transient lipid accumulation in enterocytes which may result in a delayed triglyceride efflux from the enterocytes into the circulation.
Larsen
L F
LF
Centre for Advanced Food Studies, Technical University of Denmark, Lyngby, Denmark.
Marckmann
P
P
Kornerup Hansen
A
A
Bukhave
K
K
D000818:Animals; D003060:Cod Liver Oil / Q000008:administration & dosage*; D004195:Disease Models, Animal; D020895:Enterocytes / Q000187:drug effects / Q000378:metabolism*; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D019518:Postprandial Period / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*; D014304:Triolein / Q000378:metabolism; D014316:Tritium
D014280:Triglycerides; D014316:Tritium; D014304:Triolein; D003060:Cod Liver Oil