ACKMAN ET AL.: FATTY ACIDS IN ATLANTIC STURGEON 



white layer 2-3 mm in thickness between the 

 epidermis and the soft orange layer. 



Lipid from the orange tissue of fish A was ex- 

 tracted by blending with n-hexane in a Waring 

 Blender.' All other lipids were extracted by the 

 method of Bligh and Dyer (1959). For fish A the 

 samples examined, and lipid recoveries, were liver, 

 S.59c, orange tissue, 47.2'^; muscle freed of all visi- 

 ble orange tissue and fat, 2.0%; and whole steak 

 section, 7.2%. Lipid recoveries from fish B samples 

 were liver, 8.5%; orange tissue, 25.0%; muscle freed 

 of all visible orange tissue and fat, L2%; and sub- 

 dermal white layer, L3%. Total lipids from the fish 

 A samples were saponified and non-saponifiable 

 materials removed. The recovered fatty acids were 

 converted to methyl esters with boron trifluoride 

 in methanol. White layer and orange tissue 

 samples from fish B were treated similarly, but the 

 muscle and liver lipids were fractionated on a 

 column of divinylbenzene copolymer beads and 

 eluted with benzene. The purity of the various 

 fractions was monitored by thin-layer chroma- 

 tography on silicic acid. The major fractions, the 

 triglycerides and the polar lipids with the mobility 

 of phospholipids, were transesterified with BFg- 

 MeOH. Analyses of recovered methyl esters of 

 fatty acids are given in Tables 1 and 2. Further 

 details of these methods, including gas-liquid 

 chromatography of methyl esters on open-tubular 

 polyester columns, will be found elsewhere (Sipos 

 and Ackman 1968; Ackman, Hooper, and Frair 

 1971; Ackman and Hooper 1973). 



RESULTS AND DISCUSSION 



The triglycerides in the two marine A. 

 oxyrhynchus were distributed throughout the 

 body in the dorsal fatty layer, in the form of 

 muscle infiltration by this fatty layer, and also in 

 the liver. This is most clearly made evident by 

 comparing the iodine values of the different fats 

 isolated from sturgeon B (Table 2). The white 

 subdermal layer, the orange tissue fat, estimated 

 from thin-layer chromatograms to be >95% 

 triglycerides, and the triglycerides isolated from 

 muscle and liver lipids, all have calculated iodine 

 values in the range 132-139. The two phospholipid 

 fractions have much higher iodine values, as ex- 

 pected for this class of lipids (Ackman 1966). In fish 



A, the orange tissue fat (a clear oil, estimated to be 

 >95% triglycerides from thin-layer chroma- 

 tograms) had a calculated iodine value of 186 (Ta- 

 ble 1). The liver lipid, also estimated to be mostly 



Table 1. -Fatty acid composition, in weiglit percent,' for lipids 

 recovered from four tissues of Atlantic sturgeon A. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



'NSA = no significant amount. Average percentages for some 

 minor components were: Iso 14:0, 0.07%; 4,8,12-TMTD, 0.03%; 

 2,6,10,14-TMPD, 0.03%; 19:0, 0.09%; 20:0, 0.04%; 14:1tD7, 0.02%; 

 15:10)8, 0.3%; 19:1o)10, 0.07%; 19:1o)8, 0.06%; 20:1o)5, 0.01%; 

 22:10)9, 0.04%; 22:10)7, NSA; 22:10)9, NSA; 16:2o)7, 0.02%; 

 18:20)9, NSA; 20:2o)9, NSA; 16:30)3, NSA. 



23,7,1 1,15-TMHD (phytanate) = 3,7,1 1,1 5-teframethylhexadeca- 

 noic acid. 4,8,12-TMTD = 4,8,12-trimethyltrldecanoic acid. 2,6,10, 

 14-TMPD (pristanate) = 2,6,10,14-tetramethylpentadecanoic acid. 



839 



