hemorrhagic areas beneath the skin indicated a nutritional deficiency 

 very probably an avitimonosis. This condition is believed to have 

 been created by viscera which had been allowed to partially decompose 

 before freezing. Attempts to duplicate the breakdown using properly 

 prepared viscera were unsucessful in subsequent trials. 



In the 2li-week experiments conducted in 19W, the high level 

 salmon viscera diets again showed evidence of an excessive mortality 

 in the stock (Table 5, Diets 15 and 16) . In this instance the mortality 

 was correlated with a vitamin deficiency during the cold-water period. 

 The losses in these lots were normal for the first four weeks and then 

 accelerated until they peaked between the tenth and twelfth weeks of 

 feeding from which point they rapidly declined and remained normal 

 for the remainder of the experimental period. Examination of moribund 

 fish during and prior to the peak of the mortality showed no indication 

 of an anemia but symptoms of a pantothenic acid deficienpy as demoni- 

 strated by excessive fusion of both the gill lamellae and filaments. 

 According to Phillips, et. al. (19^6) > the pantothenic acid re- 

 quirement of trout is a function of body weight and is not affected 

 by water temperature. The food intake of salmon and trout is also 

 a function of body weight in that as the weight of the fish increases 

 the percentage of food ingested decreases. The food intake is af- 

 fected by another factor— water temperature. As the water temperature 

 increases the food intake of the fish also increases (see Table 1). 

 During periods of relatively-constant, cold-water temperatures, a diet 

 which contained minimal amounts of pantothenic acid would be adequate 

 while the fish were small and the food intake was high in proportion 

 to the body weight. As the fish increased in size, the requirement 

 would increase but the percentage of food intake would be reduced pro- 

 viding no increase in water temperature occurred to accelerate the 

 intake. Thus a deficiency could develop in fish fed diets containing 

 the minimal pantothenic acid requirement during periods of prolonged 

 cold water temperatures. This deficiency could correct itself as the 

 water temperature rose with a resultant increase in the food intake 

 of the fish, sufficient to meet the vitamin requirement. 



Figure 1 dfemonstrates the relationship between water temperature, 

 food intake, and mortality in a diet containing a high level of sal- 

 mon viscera fed during 19h&\ It will be noted that the mortality 

 peaked during the period of cold water temperatures while the food 

 intake was practically constant and declined sharply with the advent 

 of warmer water and an acceleration in the food intake. 



Although the symptoms of a pantothenic acid deficiency were the 

 only ones recognized, it is very probable that other vitamin deficien- 

 cies were present in these fish. According to Karrick and Edwards 

 (19W), salmon viscera contains a reduced amount of thiamin, riboflavin, 

 and niacin 'when compared with either beef of hog liver. Using the require- 

 ments of trout for these vitamins as reported by Phillips 



15 



