To investigate interactive effects of dietary fatty acid composition and energy restriction on body lipid metabolism and its regulation, rats were fed for 10 weeks diets varying in fat type and energy intake level. Energy deficiency was achieved by removing carbohydrate from the diets while keeping fat and other nutrient intakes constant. Tissue fatty acid deposition was influenced by the interaction between the dietary fat source and body energy balance. Less total fatty acids were deposited in livers of the ad libitum beef tallow-fed animals than the other fat feedings. However, such difference no longer existed when energy intake was restricted. Similarly, less energy supply eliminated the higher docosahexaenoic acid and lower arachidonic acid contents associated with the fish oil feeding in hepatocyte membrane phosphatidylchohne, phosphatidylserine and sphingomyelin. Tissue lipogenesis was also examined as a function of the interaction of dietary fatty acid composition and energy restriction. Comparable absolute cholesterol synthesis rates were observed in livers of the food restricted animals fed different types of dietary fat, although the synthesis rates were different among the dietary fat groups fed ad libitum. Energy restriction increased the triglyceride-fatty acid synthesis rates in the intestine of the fish and safflower oil-fed groups, but not in that of the olive oil- and beef tallow-fed animals. Plasma leptin concentrations were 60% higher in the ad libitum-fed fish and safflower oil groups as compared with those in the beef tallow diet group, despite smaller perirenal fat mass and fat cell size in the fish oil-fed animals. Energy restriction decreased plasma leptin levels of the fish and safflower oil-fed rats, but not those in the beef tallow-fed animals. Taken together, these results demonstrate that the structural, functional and regulating aspects of tissue lipid metabolism were influenced by an interaction between dietary fatty acid composit
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35684 |
| Date | January 1998 |
| Creators | Cha, Ming Chuan, 1955- |
| Contributors | Jones, Peter J. H. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (School of Dietetics and Human Nutrition.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001657203, proquestno: NQ50127, Theses scanned by UMI/ProQuest. |
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