Dietary Lipid and Intestinal Brush Border Membrane Phospholipid Fatty Acid Composition and Glucose Transport of Channel Catfish

Although the influences of dietary carbohydrate and protein on intestinal brush border membrane functions are well known, the responses to different dietary lipids are less clear, particularly for ectotherms. Therefore, we examined intestinal brush border membrane phospholipid fatty acid composition and rates of glucose transport of catfish fed two diets with different fatty acid profiles. Intestinal brush border membranes of fish fed a diet containing stearic acid had higher concentrations of monoenes, dienes, and trienes but were lower in polyenes and had a lower unsaturation index than those of fish fed a diet with menhaden oil. Rates of glucose transport at low, mid, and high temperatures were higher for intact tissues and vesicles prepared from the brush border membrane of fish fed the stearic acid diet. Our findings indicate that dietary lipids influence intestinal brush border membrane fatty acid composition and the relationship between temperature and rates of glucose transport. However, we can not exclude the possibility that dietary lipids can induce changes in transporter site densities and/or the physical characteristics of membrane microdomains in which the transporters might reside.