Digestion, Absorption and Effects on Cholesterol Absorption of Menhaden Oil, Fish Oil Concentrate and Corn Oil by Rats

Abstract

Adult male rats were surgically provided with a drainage catheter in the left thoracic lymphatic channel and an indwelling duodenal catheter for constant infusion of physiological saline-5% glucose. After an overnight fast, animals were given a single duodenal dose of an aqueous emulsion containing one of the following: oleic acid, corn oil, menhaden oil or a fish oil concentrate (FOC) and [1,2-3H]cholesterol. Digestion and absorption were estimated by recovering the total fatty acids in the thoracic duct lymph over a 24-h collection period (after subtraction of the "baseline" endogenous fatty acids in the lymph). Cholesterol absorption in the thoracic duct lymph was significantly reduced (P less than 0.05) in the presence of menhaden oil or FOC compared to that in the presence of corn oil. With various fat feedings, the major increases in lymph fatty acids were directly related to the dietary fatty acid content. The relative amounts of eicosapentaenoic acid (EPA) and arachidonic acid (AA) in the thoracic lymph were influenced by the lipid content of the emulsion. The EPA/AA ratio in control, oleic acid and corn oil feedings ranged from 0.12 to 0.25. When marine oil was administered, the EPA/AA ratio was 0.78-0.98. The total amount of fatty acids found in the lymph after marine oil feeding was significantly less (P less than 0.01) than that found after corn oil feeding. The results suggested that the digestion and absorption of menhaden oil and FOC were decreased as compared with corn oil. The EPA/AA ratio was increased in the thoracic lymph after dietary fish oil feeding.

A Comparative Study of Lipids Extracted from Herring Roe Products and Fish Oil on Plasma Glucose and Adipocytokine Levels in ICR Aged Mice

“…This is consistent with our previous study on kazunoko lipids where they did not appear to influence levels of liver T-chol ). An intake of n-3 PUFA inhibits the absorption and synthesis of, and enhances the degradation of cholesterol (Choi et al, 1989;Chen et al, 1987;Smit et al, 1994). The 20:5n-3 and 22:6n-3 content of the kazunoko diet was lower compared with the fish oil diet, even though fish oil was produced in order to have the same fatty acid percentages as in the kazunoko lipids (Table 1).…”

Digestion and absorption of polyunsaturated fatty acids

“…Then Chen et al (1987b) (Hamazaki et al, 1987 (Gangl and Ockner, 1975). Although the intestine was an actively metabolizing tissue, it oxidized very little of the exogenous fatty acids.…”

“…In MaxEPA, a purified fish oil preparation, eicosapentaenoic acid occupies both the 2-and 1-, 3-positions and docosahexaenoic acid preferentially the 2-position (Chernenko et al, 1989 (Brindley, 1977; Thomson, 1978;Friedman and Nylund, 1980; Thomson and Dietschy, 1981;Tso and Simmonds, 1984;Bernard and Carlier, 1989;Thomson et al, 1989). Conversely, long-chain polyunsaturated fatty acid triglyceride digestion and absorption studies began only a few years ago (Nelson and Ackman, 1988) and sometimes gave conflicting results (McDonald et al, 1980;Chen et al, 1987b;Nilsson et al, 1987;Chernenko et al, 1989;Pavero et al, 1989). The assumption of most investigators was that polyunsaturated fatty acids are digested and absorbed through normal processes similar to those of mono-unsaturated long-chain fatty acids.…”

Regulation of intestinal NPC1L1 expression by dietary fish oil and docosahexaenoic acid

“…Polyenoic fatty acids derived from fish oil (n-3 fatty acids) have been shown to decrease cholesterol absorption (20)(21)(22) and reduce plasma cholesterol in both animal models and humans (23)(24)(25)(26)(27)(28)(29). The mechanism for how fish oil-derived fatty acids interfere with cholesterol absorption is not clear.…”