KIKER. SMITH, and VOLXG: EFFECT OF DIETARY FISH OIL 



fatty acids found within and among the tissues 

 examined. All the fatty acids that were identi- 

 fied will be discussed in the next section. For 

 illustrative purposes. Table 5 presents selected 

 results obtained with the various tissues. The 

 outer backfat had the lowest total concentration 

 of saturated fatty acids of all the tissues, regard- 

 less of whether the diet contained menhaden 

 oil or did not contain it. The remaining- tissues 

 (inner backfat. liver, and lonpissimus doisi) 

 were all higher than the outer backfat and did 

 not differ markedly from each other in the total 

 concentration of saturated fatty acids. 



The difference in degree of saturation when 

 confined to comparisons between the inner and 

 outer backfat is in agreement with rei^orts l\v 

 Banks and Hilditch (1932) and Sink, Watkins, 

 Ziegler, and Miller (1964). The simple ratio 

 of the total quantity of saturated to unsaturated 

 fatty acids, however, does not describe the true 

 character of the unsaturated fatty acids found 

 within the tissues or among them. 



An examination of the quantity of unsatura- 

 tion on the basis of the number of double bonds 

 and the relative quantities of the corresponding 

 fatty acid groups indicates marked differences 

 among the tissues. 



Both the longissimns do)-si tissue and the liver 

 tissue contain markedly less fatty acids with one 

 unsaturated bond than do either of the back- 

 fat tissues, regardless of the dietary treatment. 

 This difference no doubt is reflected by the 18:1 

 co9 content. 



The concentration of fatty acids with two un- 

 saturated bonds in the outer backfat tissue is 

 higher than that in the remaining tissues and 

 apparently indicates a differential concentration 

 of 18:2 w6. 



The difference most evident among the tis- 

 sues with respect to the fatty acids with three 

 unsaturated bonds is the higher concentration 

 found in the liver tissue. 



Both the longissimus dorsi and the liver tissue 

 contained considerably more of the four-unsatu- 

 rated-bond fatty acids than did the backfat tis- 

 sues. The liver, in turn, contained about four 

 times the concentration found in the Inngissimus 

 dorsi. Incorporating menhaden oil into the diet 



lowered the magnitude of these differences 

 among the tissues. 



The relative differences among the tissues in 

 the case of the longissimns dorsi tissue reflect 

 about equal quantities of the isomeric fatty acids 

 20:4 ojG and 20:4 coo. The concentration of the 

 fatty acids with four unsaturated bonds in the 

 liver tissue is due jirimarily to the 20:4 w6 iso- 

 mer; only small concentrations of the 20:4 w3 

 isomer were found. 



Similarly, the concentration of fatty acids 

 with five and six unsaturated bonds in the lon- 

 gissimns dorsi and liver tissues was markedly 

 higher than in the l)ackfat tissues. The incor- 

 lioration of menhaden oil into the diet resulted 

 in increased concentrations of these fatty acids 

 in all tissues, although the differences among 

 tissues were of the same magnitude as the dif- 

 ferences occurring in the absence of the men- 

 haden oil. The variable concentrations of the 

 fatty acids with five and six unsaturated bonds, 

 owing to treatment differences, reflect differ- 

 ences in the quantities of 20:5 coo. 22:. 5 coo, and 

 22:6 w3 fatty acids. 



On the basis of the equivalent degree of un- 

 saturation obtained by the multiplication of the 

 number of unsaturated bonds by the quantity of 

 fatty acids of that category, the relative degree 

 of unsaturation of the four tissues is: inner 

 backfat, 8-5.9; outer backfat, 98.7; longissimus 

 dorsi. 106.4; and liver, 164.0. The incorporation 

 of menhaden oil did not change the relative dif- 

 ferences among tissues, but it did result in a 

 treatment difference. The relative degree of 

 unsaturation among the treatments was of the 

 magnitude of 10 to 30 units greater for all tis- 

 sues exce])t the loiigissimus dorsi. 



Thus, these results generally conform with 

 those previously reported that various tissues 

 differ in fatty acid comjiosition (Brown and 

 Deck, 1930: Banks and Hilditch, 1932; Sink 

 et al, 1964) and that dietary oils alter this fatty 

 acid jjattern and degree of unsaturation of the 

 animal tissues of monogastric animals (Ellis 

 and Isbell, 1926a, 1926b; Ellis and Zeller, 1930; 

 Ellis, Rothwell, and Pool, 1931; Bhattacharya 

 and Hilditch, 1931; Hilditch and Pedelty, 1940). 



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