Lack of protective effect of menhaden oil supplementation on rat liver
steatosis induced by a carbohydrate-rich diet.
Delzenne NM, Hernaux NA, Taper HS
Departement des sciences pharmaceutiques, Universite catholique de Louvain,
Brussels, Belgium.
Liver steatosis is often attributed to dietary habits. Our previous
results have shown that fatty acid synthesis is considerably increased
by high carbohydrates-fat free diet (HCFF) given to rats after fasting,
and leads to lipid accumulation and morphological alterations in the liver,
defined as steatosis. As n-3 polyunsaturated fatty acids are able to counteract
lipogenesis induction in vivo and in vitro, we hypothesized that the addition
of menhaden oil in a carbohydrate-rich diet might be able to protect the
liver against steatosis induced by a fasting-re-feeding transition. Male
Wistar rats were first fasted for 48 hr, then re-fed ad lib. for 24 hr
with either (1) standard diet; (2) high carbohydrates-fat free diet (HCFF),
containing 40% (w/w) starch, 40% saccharose, 16% casein and 4% vitamin
mineral mix; or (3) the latter diet containing additionally 5% menhaden
oil (HCMO) for 24 hr. Triglyceride (TG) accumulation occurred in liver
tissue of rats re-fed with HCFF and HCMO diets after fasting. The addition
of menhaden oil led to a strong decrease in serum TG; however, both TG
and phospholipid (PL) levels, as well as fatty acid synthase activity,
were increased in the liver of HCMO rats as compared with the values obtained
in HCFF re-fed rats. Histologically diagnosed steatosis was even more severe
when rats received HCMO than HCFF. These results indicate that menhaden
oil supplementation does not avoid, but even increases, the degree of steatosis
generated in vivo by re-feeding a high carbohydrate diet after fasting.
PMID: 9687962, UI: 98351248