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 intesti nal brush border membrane functions are well known, the responses to d ifferent dietary lipids are less clear, particularly for ectotherms. T herefore, we examined intestinal brush border membrane phospholipid fa tty acid composition and rates of glucose transport of catfish fed two diets with different fatty acid profiles. Intestinal brush border mem branes of fish fed a diet containing stearic acid had higher concentra tions of monoenes, dienes, and trienes but were lower in polyenes and had a lower unsaturation index than those of fish fed a diet with menh aden oil. Rates of glucose transport at low, mid, and high temperature s were higher for intact tissues and vesicles prepared from the brush border membrane of fish fed the stearic acid diet. Our findings indica te that dietary lipids influence intestinal brush border membrane fatt y 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/o r the physical characteristics of membrane microdomains in which the t ransporters might reside.