ACKMAN ET AL.: FATTY ACIDS IN ATLANTIC STURGEON 



triglyceride by thin-layer chromatography, had a 

 similar iodine value, as did the lipid from the steak 

 section of high fat content. This high fat content 

 appears to be normal as Fraser et al. (1961) 

 reported 6.2% fat in a steak from this species. 

 Evidently, the fatty acid compositions of 

 triglycerides for fish A would give high iodine 

 values similar to those for phospholipids, for 

 example in the lean muscle extract which would 

 include about half of each type of lipid. The actual 

 iodine value of the triglyceride of sturgeon A is 

 unusually high for marine fish triglycerides (Ack- 

 man 1966) but a considerable range of iodine 

 values appears possible for sturgeon depot fats. 

 The "peritoneal cavity" depot fat of the A. ^turio 

 examined by Lovern (1932) had an iodine value of 

 126.5, and that of the corresponding liver lipids 

 was 125. A Pacific coast sturgeon (species un- 

 known) had body and liver oils with respective 

 iodine values of 90 and 95 (Bailey et al. 1952), and 

 the iodine values of fats of three types of flesh 

 from the freshwater A. sturio of Reichwald and 

 Meizies (1973) were also low. Two yl. baeri kept in 

 captivity for several years in the Freshwater 

 Fisheries Research Laboratory in Tokyo were 

 slightly different from each other in fatty acid 

 compositions (Table 3) but the fats in each body 

 sample, dorsal flesh and ventral flesh, were re- 

 spectively quite similar in each fish although they 

 differed in some details from the liver fatty acids 

 (Shimma and Shimma 1968). These authors 

 specifically note the absence of mesentary fat (cf. 

 Lovern 1932), although they found the testes to be 

 unexpectedly high in fat. Oil from American stur- 

 geon of unspecified origin had an iodine value of 

 125.3 (Bull 1899) and the liver oil from A. mikadoi 

 an iodine value of 157.7 (Tsujimoto 1926). Russian 

 data shows Caspian and Atlantic sturgeon fats as 

 having respective iodine values of 122 and 125 

 (Zaitsevetal. 1969). 

 In comparative detail, the fatty acid analyses 



from sturgeon A show little differences between 

 the fat from steak section, orange tissue, lean 

 muscle, and liver (Table 1). However, the high 

 proportions of 22:6 <d3 in the lean muscle and in the 

 Hver may reflect inclusion of phospholipids which 

 contained relatively high proportions of 22:6<«)3 

 (compare fish B, polar lipids. Table 2). The analysis 

 of particular lipids from fish B is more appropriate 

 for detailed discussion. The fatty acid composition 

 shows that fat from the subdermal white layer, the 

 orange tissue fat, and the muscle triglycerides are 

 all essentially the same fat. Hake skin fats 

 {Merhiccius cape)isis and M. paradoxua) resemble 

 adjacent dark muscle fat in fatty acid composition 

 (Wessels and Spark 1973). The fatty acid composi- 

 tion of triglycerides in the liver of sturgeon B is 

 also basically similar but has a few fatty acid 

 characteristics shared with the liver phospholipids. 

 Thus the level of 14:0 is lower and the proportion of 

 16:0 is higher. However 18:0 is not affected in the 

 liver triglyceride, relative to the other 

 triglycerides, so there is no effect on the total of 

 saturated acids. The total for monoethylenic acids 

 in the liver triglycerides is also nearly the same as 

 in the other triglycerides. Although in detail the 

 16:1 acids are less in parallel to the phospholipid 

 composition, the 18:1 acids are unexpectedly 

 higher, a characteristic confirmed by fish A liver 

 (Table 1). This intermediate status of the liver 

 triglycerides is also apparent in many details and 

 subtotals among the polyunsaturated acids. A 

 singular exception lies in the low proportion of 

 20:4<i)6, which does not seem to extend to any other 

 "o)6" acid. On the other hand, the observation that 

 20:5to3 in the liver triglyceride is not intermediate 

 between the other triglycerides and the liver 

 phospholipid is offset by the higher level of the 

 homologous 22:5ft)3. In fish A it is possible that 

 20:4<o6 is also low in liver lipid (of which a large 

 proportion would be triglyceride) but the lower 

 level of 20:5a)3 is less marked in the fatty acid 



Table 3.-Some fatty acid details, in weight percent, for fats from tissues of three sturgeon 

 examined in Japan (from Shimma and Shimma 1968). 



841 



