Effects of dietary cholesterol and type of dietary carbohydrate on hepatic and plasma glycerides and phospholipids in the gerbil.

The influence of dietary cholesterol at levels of 0.01-0.5% (by weight) and carbohydrate type (starch, sucrose or a starch-sucrose mixture) on levels and composition of hepatic and plasma glycerides in the male Mongolian gerbil (Meriones unguiculatus) was studied. Hepatic and plasma triglyceride (TG) levels were generally higher with dietary cholesterol supplementation (0.1 and 0.5%), and animals fed sucrose diets exhibited very low levels of hepatic and plasma TG. The mixed carbohydrate (starch-sucrose) did not affect glycerides in a way that could be interpolated from feeding starch or sucrose diets alone. The percent of 16:0 in liver TG was depressed with cholesterol-feeding (at the 0.5% level only), whereas the percent of 18:1 was elevated. Sucrose diets produced higher percentages of 18:0 in liver TG. Dietary cholesterol elevated concentrations of plasma but not liver phospholipid (PL). Percentages of 20:40 omega 6 and 22:6 omega 3 acids in liver and plasma PL were significantly depressed by cholesterol supplementation, whereas the percent of 18:2 in liver PL was higher when feeding cholesterol and starch (no sucrose). Dietary cholesterol produced higher levels of hepatic 1,2-diglyceride with lower percentages of 18:0 and 20:4 omega 6 and higher percentages of 18:1 and 18:2. Dietary cholesterol may possibly influence fatty acid elongation and desaturation reactions as well as transacylation reactions in phospholipid synthesis. In this regard, compositional data suggested a suppressing effect of dietary cholesterol on 22:6 omega 3 formation as exemplified by a 40% diminution in the docosahexaenate content of hepatic phosphatidylethanolamine in gerbils fed a 0.5% cholesterol diet for only 7 days.