Effects of dietary oils prepared from the internal organs of the Japanese giant scallop (Patinopecten yessoensis) on cholesterol metabolism in obese type‐II diabetic KK‐A(y) mice

Our research team has successfully prepared high‐quality scallop oil (SCO), containing high eicosapentaenoic acid (EPA) and phospholipids (PL) from the internal organs of Japanese giant scallop (Patinopecten yessoensis) which is the largest unutilized marine resource in Japan. In this study, we prepared SCOs from scallop internal organs obtained from Mutsu (Aomori) and Uchiura (Hokkaido) bays in Japan, and named them SCO‐M and SCO‐U, respectively. This study aimed to investigate the effects of dietary SCO‐M and SCO‐U on cholesterol metabolism in obese type‐II diabetic KK‐A(y) mice. Four‐week‐old male KK‐A(y) mice were divided into four groups. The Control group was fed with AIN93G‐modified high‐fat (3 wt% soybean oil + 17 wt% lard) diet, and the other groups were fed with high‐fat diet, in which 7 wt% of the lard contained in the Control diet was replaced with SCO‐M, SCO‐U, or tuna oil (TO). After the mice had been fed with the experimental diet for 49 days, their serum, liver, and fecal lipid contents, as well as their liver messenger ribonucleic acid expression levels, were evaluated. The SCO‐M and SCO‐U groups were significantly decreased liver cholesterol contents compared to those of the Control and TO groups, partially through the enhancement of the fecal neutral sterol excretions and the tendency to increase the cholesterol 7α‐hydroxylase expression level of the liver. These results indicated that dietary SCO‐M and SCO‐U exhibited cholesterol‐lowering functions in the liver that can help prevent the development of lifestyle‐related diseases.