THE EFFECTS OF DIETARY « -TOCOPHEROL AND TUNA, 

 SAFFLOWER, AND LINSEED OILS ON THE FLAVOR OF TURKEY 



L. Crawford,! j) w Peterson,^ M. J. Kretsch,i A. L. Lilyblade,^ and H. S. Olcott^ 



ABSTRACT 



Turkeys were fed varying levels of a -tocopherol acetate and oils containing linolenates (linseed and 

 tuna oils). As expected, these oils caused a fishy flavor to develop in the turkey carcass, anda -tocopherol 

 fed concomitantly, greatly retarded development of this fishy flavor, but did not affect the uptake of 

 linolenates by the turkey carcass. These and other observations pointed to the conclusion that linole- 

 nates do not by their simple presence in turkey carcass cause fishy flavor, but that perhaps their in vivo 

 and/or postmortem oxidation are responsible for the development of this flavor. 



Several investigators have reported that fishy 

 flavors develop in poultry carcass when diets are 

 supplemented with oils, such as linseed oil ( Klose 

 et al., 1951) and fish oil (Neudoerffer and Lea, 

 1966, 1967, 1968; Miller et al., 1967a, 1967b; Mil- 

 ler and Robisch, 1969; Dreosti, 1970; Opstvedt, 

 Olsen, and Urdahl, 1970; Opstvedt, Nygard, and 

 Olsen, 1970, 1971). The latter investigators 

 showed that this off flavor is related to the linole- 

 nate content of the oil, especially the long chain 

 homologues. Miller and Robish ( 1969) showed 

 that fishy flavors were eliminated with the with- 

 drawal offish oils and substitution of a more satu- 

 rated fat (like tallow) in the diet. Lineweaver 

 (1970) reported that practical experience has 

 shown that the amount of fish oil in the diet of 

 poultry should not exceed 0.3% if fishy flavors are 

 to be avoided. However, it was not clear whether 

 the specific character of the oil (co3 fatty acid con- 

 tent) was a factor to be considered. 



Lea et al. ( 1966), Dreosti ( 1970), and Opstvedt et 

 al. (1971) reported that antioxidant-treated fish 

 meal is more likely to cause fishiness than un- 

 treated meal. They reasoned that the unsaturated 

 fatty acids of the untreated meal become oxidized 

 and, perhaps, polymerized, thereby becoming un- 

 available for uptake in the tissue. 



The research of Mecchi, Pool, Beham, Hamachi, 

 and Klose (1956) showed that the stability of tur- 

 key fat closely paralleled the tocopherol content of 

 the fat. Other work by Mecchi, Pool, Nonaka, 

 Klose, Marsden, and Lillie (1956) whereby chick- 

 ens and turkeys were fed varying levels of dietary 



'Western Regional Research Laboratory, Agricultural Re- 

 search Service, U.S. Department of Agriculture, Berkeley, CA 

 94710. 



^Department of Avian Science, University of California Ag- 

 ricultural Experiment Station, Davis, CA 95616. 



^Institute of Marine Resources, University of California, 

 Davis, CA 95616. 



tocopherol, further substantiated that in fact to- 

 copherol uptake was possibly singularly impor- 

 tant to the stability of carcass fat. These findings 

 are corroborated in more detailed studies by 

 Webb, Marion, and Hayse ( 1972) and Webb, Brun- 

 son, and Yates (1972). 



Dreosti (1970) and Opstvedt et al. (1971) re- 

 ported that dietary a -tocopherol acetate sup- 

 plementation (above levels required to prevent 

 nutritional disease) significantly reduced fishy 

 flavors in poultry fed fish oils. 



It is clear that dietary oils containing cj 3 fatty 

 acids do in some way contribute to fishy flavors in 

 poultry and that « -tocopherol acetate supplemen- 

 tation reduces the development of this flavor. It is 

 not clear howa;3 fatty acids, when ingested by 

 poultry, result in fishy flavored carcasses or how 

 a; -tocopherol reduces the development of this 

 flavor. This paper reports on the fatty acid compo- 

 sition of extracted lipids and on the flavor of the 

 meat from turkeys fed fish oil and linseed oil to 6 

 wk and to 8 wk of age using safflower oil or beef fat 

 to bring diets into lipid isocaloric balance. Sup- 

 plemental tocopherol acetate was added to some of 

 the diets. The flavor of adult turkeys fed tuna oil 

 for 2 wk was also observed. 



While it is not a practice to raise turkeys to only 

 6 and 8 wk of age or to feed fish oil midstream for 

 only 2 wk, it was convenient and expedient for the 

 present study. Additionally, observations can be 

 made on the relative uptake of dietary fats and the 

 influence of metabolic rate. 



EXPERIMENTS 

 Oils 



Linseed oil, refined safflower oil, freshly ren- 

 dered beef fat, and fresh polished tuna oil (alba- 

 core) were obtained unstabilized. The oils were 



Manuscript accepted January 1974. 

 FISHERY BULLETIN: VOL. 72, NO. 4, 1974. 



1032 



