800 VII. LIPID DISTRIBUTION IN SPECIFIC TISSUES 



iodine value of milk fat, usually about 4 to 5 points, 526 - 627 while less oleic 

 and more lauric and myristic acids were present in the milk fat. 628 



Brown et al. b26 found that, when soybean oil was given, the iodine value 

 of the butterfat was increased as much as 40%. The iodine value of milk 

 fat was also increased by the feeding of linseed oil. 629 When linseed or 

 rapeseed oil was fed, the amount of palmitic acid in the milk fat was de- 

 creased, while that of oleic and of octadecadienoic acid was increased. 629 

 After the administration of cod-liver oil, Hilditch and Thompson 529 found 

 an increased proportion of C 2 o- and C22-unsaturated fatty acids, as well as of 

 oleic acid, together with a decrease of butyric acid by as much as 50%. 

 Peanut oil feeding resulted in an increase in the proportion of oleoglycerides, 

 together with a decrease of the butyric to decanoic acid glycerides. 530 On 

 the other hand, when palm kernel oil was fed, the C12- and Ci 4 -glycerides 

 were increased, while the Cie-glycerides and the oleate content were de- 

 creased. Smith and Dastur 531 reported that a low dietary level resulted in 

 a reduction of the proportion of C 4 - to Ci 4 -saturated glycerides, by about 

 80%, together with a decrease in the C14- and Ci6-unsaturated acids. On a 

 low dietary level, oleic acid was increased. Maynard et al. b32 reported that 

 the administration of unsaturated fats to cows was reflected by a change of 

 iodine number of the milk fat within eighteen hours; the maximum effect 

 of the ration was noted within three or four days. 



In the case of goats, increased saturation of the milk fat resulted from 

 the administration of a low-fat diet or of one containing coconut oil ; in the 

 latter case the molecular weight of the average fatty acids was lower than 

 it was on high-fat diets. 533 



The relationship of ingested fat to milk fat has also been demonstrated 

 by the presence of certain "marked" fatty acids in milk fat after they had 

 been fed to lactating animals. The best examples of this type of proof 

 have been obtained with iodized fats by Aylward and co-workers, 634 with 

 odd-chain synthetic fats by Appel and collaborators, 635 and with cod-liver 

 oil, which contains characteristic highly unsaturated fatty acids, by Hil- 

 ditch and Thompson. 629 



626 W. C. Brown, R. B. Dustman, and C. E. Weakley, /. Dairy Set., 24, 265-275 (1941). 



627 O. J. Hill and L. S. Palmer, J. Dairy Sci., 21, 529-544 (1938). 



528 T. P. Hilditch and J. J. Sleightholme, Biochem. J., 24, 1098-1113 (1930). 



629 T. P. Hilditch and H. M. Thompson, Biochem. J., 30, 677-691 (1936). 



s3 ° T. P. Hilditch and H. Jasperson, Biochem. J., 37. 238-243 (1943). 



631 J. A. B. Smith and N. N. Dastur, Biochem. J., 32, 1868-1876 (1938). 



832 L. A. Maynard, C. M. McCay, and L. L. Madsen, /. Dairy Sci., 19, 49-53 (1936). 



633 R. C. Bender and L. A. Maynard, J. Dairy Sci., 15, 242-253 (1932). 



634 F. X. Aylward, J. H. Blackwood, and J. A. B. Smith, Biochem. J., 31, 130-137 

 (1937). 



635 H. Appel, H. Bohm, W. Keil, and G. Schiller, Z. physiol. Chem., 282, 220-244 (1947) 



