LACK OF PROTECTIVE EFFECT OF MENHADEN OIL SUPPLEMENTATION ON RAT-LIVER STEATOSIS INDUCED BY A CARBOHYDRATE-RICH DIET

Liver steatosis is often attributed to dietary habits. Our previous re sults have shown that fatty acid synthesis is considerably increased b y 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 ab le to counteract lipogenesis induction in vivo and in vitro, we hypoth esized that the addition of menhaden oil in a carbohydrate-rich diet m ight be able to protect the liver against steatosis induced by a fasti ng-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) hig h 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. Triglyc eride (TG) accumulation occurred in liver tissue of rats re-fed with H CFF and HCMO diets after fasting. The addition of menhaden oil led to a strong decrease in serum TG; however, both TG and phopholipid (PL) l evels, 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 ra ts received HCMO than HCFF. These results indicate that menhaden oil s upplementation does not avoid, but even increases, the degree of steat osis generated ill vivo by re-feeding a high carbohydrate diet after f asting. (C) 1998 Elsevier Science Ltd. All rights Reserved.