DIETARY-FAT AND ADIPOSE-TISSUE METABOLISM IN RUMINANTS, RIGS, AND RODENTS - A REVIEW

Effects of dietary fat on dairy cows are reviewed. Dietary fat did not affect gain in BW or body condition score after peak lactation but te nded to increase BW loss during early lactation and body fat depositio n in growing cattle. Dietary fat decreased de novo fatty acid synthesi s in adipose tissue. Basal FFA release from adipose tissue in vitro an d beta-adrenergic lipolytic responses were increased by protected poly unsaturated fatty acids. Dietary fat increased body fat in growing pig s and decreased BW loss in lactating sows. Dietary fat decreased de no vo fatty acid synthesis and basal glycerol release in adipose tissue a nd tended to increase simultaneously beta-adrenergic lipolytic respons es to increased membrane fluidity. Dietary fat increased body fat in r ats. Polyunsaturated fatty acids were sometimes less efficient than sa turated ones in increasing body fat. Lipoprotein lipase activity in ad ipose tissue generally decreased. Hepatic fatty acid synthesis was dec reased sharply by polyunsaturated fatty acids, and adipose tissue resp onse was less important. beta-Adrenergic- stimulated lipolysis decreas ed, and fatty; acid esterification increased, particularly from satura ted fatty acids. A trend toward insulin resistance, which was more mar ked with saturated fatty acids, occurred in adipose tissue.