FISHERY BULLETIN: \'0L 61. NO 2 



ner backfat, the longissimus dorsi muscle, and 

 the liver) of pigs fed various diets with and 

 without menhaden oil and for various intervals 

 of time before they are marketed. 



2. The organoleptic effect of the different di- 

 etary levels of menhaden oil on the meat of the 

 pigs and the retention or disap])earance of the 

 off-flavor by removal of menhaden oil from the 

 diet of the pigs when they reach a body weight 

 of 68.0 or 79.5 kg and are subsequently marketed 

 when they reach a weight of 90.9 kg. 



3. The relation, if any, between the detection 

 of off-fiavor and the pattern of fatty acid de- 

 liosition in the tissue samples. 



4. The metabolic interrelation of fatty acids 

 of the various fatty acids of the omega families 

 (coS, 0)6. 0)9). 



RELATION BETWEEN MENHADEN OIL 



FATTY ACIDS FED TO PIGS AND 



DEPOSITIONAL PATTERNS OF THESE 



FATTY ACIDS IN THE PIG TISSUES 



Callow (1935, 1938) indicated that the rate 

 of deposition of fat in pigs is correlated with 

 the iodine number of the fat and that slower 

 growing pigs deposit a more unsaturated fat. 

 Accordingly, we felt that our exiierimental pigs 

 should be handled so that they would develop 

 uniformly, thus minimizing the variation in the 

 composition of depot fat resulting from differ- 

 ential rates of growth. 



The first part of this experiment was a gen- 

 eral study to monitor the uniformity of growth 

 of the pigs and of the development of their car- 

 casses. That is. we wanted to determine wheth- 

 er the diets fed and our treatment of the pigs 

 would I'esult in any abnormalities that might 

 invalidate the specific findings in this first ex- 

 periment and in the other three experiments 

 to follow. 



UNIFORMITY OF GROWTH OF PIGS AND 

 OF DEVELOPMENT OF CARCASSES 



Uniformity of Growth 



Described here are the diets, the allotment 

 and management of the pigs, and the statistical 

 analyses used. 



The diets were balanced on an equal-protein 

 and equal-calorie basis and were fortified to sup- 

 ply all the known nutrients required by pigs. 

 Crude menhaden fish oil that had been stabilized 

 with butylated hydroxy toluene' was added at 

 levels of 0.4 Sr to 1.4 '^r. The oil replaced var- 

 ious proportions of cerelose and Solka Flox' to 

 give isocaloric and isonitrogenous diets (Table 

 1). The diets were mixed in a ribbon-type mix- 

 er and were pelleted weekly through a 12-mm 

 die. Steam was not used in the pelleting pro- 

 cess. Table 2 shows the gas-liijuid chromato- 

 graphic analyses of the oil and of the diets fed. 



" Level of aildition is trade secret. 

 " Trade names are used merely to simplify descrip- 

 tions; no endorsement is implied. 



Table 1. — Diet formulation used in experiment to determine the dietary level of menhaden oil that will impart off- 

 flavors to the meat of pigs. 



Sufficient (race minerals and vitamins were present to meet the reciuiremenrs of the Notional Reseorch Council. 



282 



