The Iodine Values of “Physiological” or “Synthetic” Rat Fat.

Abstract

Male albino rats taken at weaning when 21 days of age were fasted for 2 days in order that a partial depletion of the stored fat might ensue, thereby lessening its influence on the later resulting “synthetic” fat. The rats were then fed a diet consisting of 18% casein (extracted with alcohol and ether), 77% sucrose, and 5% salt mixture (Osborne and Mendel), supplemented daily by the following: a hot water extract of pig's liver (0.4 gm. dried liver), 100 mgm. of yeast concentrate (Harris), 20 mgm. of a non-saponifiable fraction of cod liver oil (a pasty material, Oscodal†—Iodine Number 110), and 0.016 mgm. of irradiated ergosterol (dissolved in alcohol). Four other groups of rats (5 or more in a group) were fed this “fat free” diet modified so that the first group received an addition of 20 mgm. of peanut oil (Iodine Number 84); the second had the non-saponifiable fraction of cod liver oil substituted by 20 mgm. of cod liver oil (Iodine Number 160); the third received the same diet as the second group with the addition of 20 mgm. of peanut oil; and the last had the extracted casein replaced by commercial casein, the yeast concentrate substituted by yeast and the irradiated ergosterol omitted.†† From the analyses of the dietary components, it is calculated that the rats on the “fat free” diet received daily probably less than 7 mgm. of fatty materials, other than the non-saponifiable matter from cod liver oil.