Summary. Effects of dietary lipids on qualitative aspects of lipogenesis in growing rat and pig.As compared to studies on very low-lipid diets ingested by growing rat and pig, the degree of deposit unsaturation may be increased by nutritional route ; large amounts of different types of unsaturated fatty acids then appear in triglyceride stores. On the other hand, it is very difficult by this method to increase their degree of saturation and saturated long fatty acid content.In the first part of this report we show the results of studies confirming this observation. The second part deals with the particular effects of some middle-chain fatty acids on the qualitative aspects of lipogenesis during growth.In the young weaned rat, we compared long-term effects of the intake of two middlechain triglycerides, glycerol trioctanoate (Tri C 8 : 0) and glycerol tridodecanoate (Tri C12 : 0). As compared to the results of feeding a lipid-free diet, glycerol trio d anoate did not change the fatty acid composition of body lipid stores, but glycerol tridodecanoate was a nutritional factor deeply affecting this characteristic. As opposed to octanoic acid, high amounts of dodecanoic acid were incorporated into triglyceride stores. They had a depressive action on the appearance of octadecenoic cis-9 acid (C18 = 1(u9) and thus increased the ratio saturated fatty acids/unsaturated fatty acids in lipid deposits.The intake of glycerol tridodecanoate gave similar results in growing pig. However, dodecanoic acid seemed to present a higher capacity for elongation into tetradecanoic acid (C12 : 0 -> C14 : 0) in rat.The metabolic effects of dodecanoic acid intake were already apparent before weaning. The young weaned rats from mothers fed glycerol tridodecanoate during growth, pregnancy and lactation, presented body lipids containing more than 25 p. 100 dodecanoic acid. This observation was associated to the fact that in these nutritional conditions, that fatty acid was incorporated at high amounts in the lipids secreted by the mammary gland.The metabolic effects of glycerol tridodecanoate intake therefore should be totally different than those of other middle-chain triglycerides having a lower molecular weight, as glycerol trioctanoate, for example.Introduction.

Summary. Ef/ects on lipid fatty acid composition in different adipose deposits of pig ingesting glycerol tri-dodecanoate (Tri C12 : 0). Introduction.