In vivo monitoring of hepatic glycolipid distribution of <i>n</i>-6&thinsp;∕&thinsp;<i>n</i>-3 in jugular-vein-cannulated rats as a nutritional research model for monogastric animal

Abstract

The metabolic distribution via blood from liver of glycerolipids by omega-6 to omega-3 fatty acid (n-6 ∕ n-3) ratio in monogastric animal nutrition is very important. In vivo monitoring technique using jugular-vein-cannulated rats as a nutritional model for monogastric animal can yield important insights into animal nutrition. This study was conducted to determine the effect of different n-6 ∕ n-3 ratios (71:1, 4:1, 15:1, 30:1) on metabolic distribution of glycerolipids newly synthesized and secreted in the liver of the rats and explore the mechanism involved. Regarding 14CO2 released from oxidation of glycerolipid metabolism, it was the highest (22.5 %) in groups with a n-6 ∕ n-3 ratio of 4:1 (P<0.05). The control group showed the highest total glycerolipid level, followed by the 30:1, 15:1, and 4:1 groups in order (P<0.05). When secreted triacylglycerol level of each group was compared with that of the control group, the 4:1, 15:1, and 30:1 groups were decreased by 36.3 %, 20.9 %, and 13.3 %, respectively (P<0.05). Regarding the distribution of phospholipid against total glycerolipid compared to the control group, the 4:1, 15:1, and 30:1 groups were 1.38, 1.29, and 1.17 times higher, respectively (P<0.05). In the comparison of 14CO2 emission against total glycerolipid compared with the control group, the 4:1, 15:1, and 30:1 groups were 1.61, 1.52, and 1.29 times higher, respectively (P<0.05). These results demonstrate that a dietary n-6 ∕ n-3 fatty acid ratio of 4:1 could significantly decrease harmful lipid levels in the blood by controlling the mechanism of metabolic distribution via blood from triglyceride and phospholipid newly synthesized in the liver of cannulated rat.