Vitamin injection studies 



At the end of 16 weeks the fish in the low- 

 calorie, low -protein diets began showing nutri- 

 tional deficiencies. These deficiencies were 

 characterized by frayed fin membranes, in 

 which the upper extremities of the fin rays be- 

 came bare and frayed; extreme emaciation due 

 to a loss of aopetite; partial retraction of the 

 head; high mo.talities; and a very noticeable 

 loss of equilibrium, in which the fish swam at 

 an angle from the horizontal with the head 

 elevated. As the deficiency increased this 

 head-up position became progressively worse, 

 until the fish were nearly vertical and helplessly 

 drifting with the current . 



Fish in all of the diets, with the exception 

 of the all-meat control, eventually showed this 

 deficiency syndrome, despite high levels of 

 meat and/or crystalline vitamin supplementation 

 in some rations. The deficiency symptoms were 

 believed to be a hypovitaminosis of one or more 

 of the B-complex vitamins . In an attempt to 

 determine which of the vitamins was lacking, an 

 experiment was designed in which affected fish 

 were injected with various B-compiex vitamins, 

 singly and in groups , in amounts equalling a 

 10 -day requirement. Twenty days and two in- 

 jections later, no noticeable alleviation of the 

 deficiencies -could be noted in any of the groups 

 with the exception of the lot receiving the entire 

 group of vitamins. In this group, the majority 

 of the fish returned to a normal swimming 

 position and began to feed readily. A chi-square 

 test on mortalities showed only the lot receiving 

 the complete vitamin complement to have a 

 significantly lower mortality than the control. 



The injection studies clearly indicated 

 that the nutritional deficiency evident in the 

 fish at the end of 24 weeks was due to an in- 

 adequate supply of the B-complex vitamins 

 available to the fish . Prior calculation of the 

 meal and meat combinations within the diets , 

 showed that these ingredients were under the 

 minimal requirements for chinook salmon as 

 defined by Halver (1957). It was hoped that by 

 supplementing the diets with a crystalline 

 vitamin package containing the full amount of 

 the B-complex group required for maximum 

 storage that the requirements would be met. 



The appearance of the nutritional deficiency in 

 all diets suggests that either the vitamin supple- 

 ment was not adequate , or that a significant 

 portion of the crystalline vitamins was unavail- 

 able to the fish either through loss by leaching 

 into the water or an antagonistic action within 

 the diets containing both meats and meals , or 

 possibly a combination of all three factors . 



An all -meal diet 



Probably the most significant result of this 

 experiment was the capability of an all -meal 

 diet , devoid of raw meat supplementation and 

 fed at 2,000 calories per kilogram, to maintain 

 fish for a 24-week period. Gains, protein 

 deposition and utilization, performance, and 

 general condition were equal to if not better 

 than comparable meat-supplemented diets . A 

 cursory gill check was run on all diets every 2 

 weeks, and it was not until the end of 20 weeks 

 tiiat any fish from this diet were found to have 

 anemic tendencies using pale gill color as the 

 criterion. Mortalities were below 5 percent for 

 the entire 24-week period and the nutritional 

 deficiency so apparent in other diets was nearly 

 lacking in this diet. Additional testing with this 

 diet is indeed warranted. 



SUMMARY 



The results of the 1962 feeding trials may 

 be summarized as follows: 



1 . At the end of the feeding trials , all of 

 the experimental diets had some fish showing 

 symptoms of a hypovitaminosis . The severity 

 of these symptoms was most pronounced in the 

 low -protein, low-calorie diets. 



2. All experimental diets, with the ex- 

 ception of the 20 -percent protein low -calorie 

 rations , produced gains comparable to or ex - 

 ceeding that produced by the control diet. 



3 . Fish fed meat supplements ranging 

 from 10 to 50 percent of the meat-meal combi- 

 nation were not measurably different in either 

 mortality, average weight, protein deposition, 

 or protein utilization. 



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