Salmon Viscera '-'omponents ?. 



This group of trials was designed to compare the food value of 

 salmon livers, salmbn milts, salmon eggs, and salmon digestive tracts. 

 The term salmon digestive tracts, as used in this paper, included the 

 pyloric caeca, spleen, stomach, intestines, and air bladder. 



The purpose of these experiments was to find a \-ia.j to use some of 

 the salmon viscera now going to waste in Alaska, At the present time, 

 viscera is not readily available because of the storage problems at the 

 canneries and the costs involved in shipping viscera to the United States. 

 To solve these problems, it was thought that the logical place to start 

 would be to find, if possible, a component of the viscera that would, by 

 reason of its superior food value for salmon, be worth more than whole 

 salmon viscera. If such a visceral product were found, perhaps its value 

 might offset the shipping charges from Alaska to points in the Pacific 

 Northwest, 



The salmon viscera used in this study, unlike the Colximbia Kiver 

 viscera used in the other diets, was obtained from Puget Sound pink 

 salmon (O. gorbuscha) . The diets in the salmon viscera component study, 

 although classed as single component diets, contained ten per cent salmon 

 viscera meal to prevent excessive leaching. This meal was tunnel-dried at 

 100° F. This addition of meal to prevent leaching may have had no small 

 effect on the health of the fish during the cold-water period and in part 

 may account for the serious mortalities suffered by the experimental fish 

 in this salmon component group. 



All of the lots in the visceral component study incurred high mor- 

 talities during the cold-water period of the first 12 weeks (Table 2). 

 The mortalities of the whole salmon viscera lot were significantly lower 

 than the salmon liver, milt, and the intestinal tract lots. There was 

 no significant difference in mortalities between the egg lot or the 

 whole salmon viscera lot. Because of the excessive mortalities ranging 

 from Uh to 68 per cent, the mean weights are not too reliable in es- 

 tablishing differences at the end of the first 12 weeks. It may be said, 

 however, that the salmon eggs produced as much growth as whole salmon 

 viscera, and that the other components produced less growth than eggs 

 or whole viscera. 



During examinations of the fish in the period of cold water, it was 

 found that as high as 25 per cent of the moribund fish in the digestive 

 tract, milt, and liver-fed lots had external hemorrhagic areas on the 

 fins, base of fins, isthmus, and gill opercula (Table 1, Diets l8, 19, 

 20). A very few fish were found to have the same trouble in the salmon 

 egg lot (Table 1, Dietl?) . According to McLaren et al. (19U7), these 

 hemorrhagic areas are symptoms of a riboflavin deficiency. Also during 

 this same period, clubbed gills, which are the usual signs of a panto- 

 thenic acid deficiency (Tunison et al,19lthjMcLaren et al,19ii7), were 

 found in each viscera-fed lot. Examinations at the end of the 



