Comparative Aspects of Lipid Metabolism: Impact on Contemporary Research and Use of Animal Models

Abstract

The emerging obesity crisis and consequent concerns for corrective measures and appropriate public policy have stimulated research into causes, prevention, remediation, and health consequences of obesity and associated maladies. Such research areas include eating behavior, appetite control, and food intake regulation as well as the regulation of lipid metabolism, cardiovascular function, endocrine function, and dyslipidemia states utilizing various animal models and cell culture systems. Although the liver has a central role in lipid/fatty acid synthesis and glucose is the precursor for de novo fatty acid synthesis in rodents and humans, in many other species, adipose tissues are the primary sites of lipogenesis. In addition, many species utilize acetic acid as a precursor for fatty acid synthesis. This fundamental difference in the site of fatty acid synthesis and the pattern of consequent lipid trafficking influences overall animal lipid metabolism and the role of regulatory hormones and transcription factors. Researchers utilizing various animal species in targeted biomedical research should be aware of these species differences when interpreting their data. In addition, many animal species are used for food production, recreational, and companion purposes. Understanding the lipid metabolism regulatory mechanisms of such species from a comparative perspective is important for the proper nutrition and health of these animals.

Co-administration of berberine and plant stanols synergistically reduces plasma cholesterol in rats

“…This discrepancy may have resulted from the differences in the diet composition, especially dietary cholesterol and fat levels, bile acid supplementation, and the time of BBR administration between the present study and previous studies [13,26,42,43]. It could also be due to the differences in cholesterol metabolism between humans and animal species [44][45][46]. In addition, it should be noted that the effect of BBR on blood cholesterol in rats was previously examined only in disease models such as diabetes or nephritis [42,43,47].…”

Dietary fat source affects metabolism of fatty acids in pigs as evaluated by altered expression of lipogenic genes in liver and adipose tissues

“…Pig de novo fat synthesis largely takes place in the adipose tissue (O'Hea and Leveille, 1969;Bergen and Mersmann, 2005). Deposition and mobilization of fat depots are regulated at several levels.…”

Fat metabolism is regulated by altered gene expression of lipogenic enzymes and regulatory factors in liver and adipose tissue but not in semimembranosus muscle of pigs during the fattening period

“…The main sites for fat synthesis in animals are liver and adipose tissue, but important species differences exist. In rodents and birds, liver is the main organ for fatty acids (FA) synthesis, but in the pig, de novo fat synthesis largely occurs in the adipose tissues (O'Hea and Leveille, 1969;Bergen and Mersmann, 2005).…”