EFFECT OF PALMITIC, OLEIC, AND LINOLEIC-A CID ON THERMOGENESIS IN SOWS

An animal model experiment was conducted with nine adult sows to study the effects of long-chain fatty acids on thermogenesis when different fatty acids were replaced for 30% of the energy of a basal diet based on cereals and soybean meal. The acids were fed as commercial product s containing as main constituent either palmitic acid, oleic acid, or linoleic acid, according to a latin square design in experimental peri ods 2 to 4. In periods 1 and 5 the sows were submitted to basal diet a lone. Digestibility of palmitic acid was only 36%, whereas the unsatur ated fatty acids were highly absorbed (90%). Interaction effects of th e undigested proportion of the long-chain fatty acids with the basal d iet in hindgut fermentation could be ruled out since a supplementary e xperiment on three sows showed no influence of infusion of oleic or li noleic acid into the caecum on the energy utilization of the basal die t. There was no significant differences in thermogenesis among the fat ty acids. Heat production in the treatment periods averaged -1.2% as c ompared to the basal diet periods. This result was in accordance with the value -1.0% calculated theoretically for the reduction in heat pro duction in the treatment periods. Thus, the data did not indicate any stimulating effect of long-chain fatty acids on beat production, and u tilization of energy of fatty acids occurred within the obligatory the rmogenesis.