TESTS OF HATCHERY FOODS FOR SALMON, 

 1953 AND 1954 



INTRODUCTION 



The feeding trials conducted at the Salmon -Cultural 

 Laboratory in 1953 and 1954 were a continuation of 

 previous experiments reported by Burrows et al. (1951), 

 Robinson et^aL (1951a), Robinson et^aL (1951b), Burrows 

 et al. (1952), and Newman et al. (1954). The objective 

 of these trials was the same as that of the previous tests, 

 the development of adequate, economical diets for 

 salmon applicable to production operations . 



In 1953, the work was directed toward the develop- 

 ment of the most efficient combinations of pretested 

 products. Although the experimental program in- 

 cluded tests with both Chinook ( Oncorhynchus 

 tshawytscha) and blueback (O. nerka) salmon finger - 

 lings an outbreak of a virus disease in the blueback 

 salmon forced the abandonment of this series of trials. 

 As a result, only the chinook experiments were carried 

 to completion. One excellent production diet was de- 

 veloped from these trials. 



In 1954, both the chinook and blueback trials were 

 carried through to completion. The blueback trials 

 were directed toward the development of diets which 

 would be virus free. The work of Watson et al.(1954) 

 indicated that the virus infection of blueback salmon 

 was carried in the food with salmon viscera as the 

 suspect carrier . Two methods of approach were used: 

 first, the evaluation of sterilized salmon viscera, and, 

 second, the development of diets devoid of salmon 

 viscera which were equal in growth potential and 

 nutritional adequacy. The results of these experi- 

 ments indicate that the sterilization of salmon jascera 

 alters the feeding consistency and possibly the bio- 

 logical value of the protein . The second phase of 

 these trials developed several practical production 

 diets from which salmon viscera was eliminated. 



The 1954 chinook experiments were directed 

 toward the development of diets containing 50 percent 

 of dry meals . Using the Cortland No. 6a meal com- 

 bination as a base the meat components were varied 

 in one part of these tests. In the second part, the 

 meal components were varied. No satisfactory diet 

 was developed from these trials . 



CONDITIONS OF EXPERIMENTS 



The methods, equipment, and techniques used 

 were essentially the same as those described by 

 Burrows et al. (1951; 1952). No changes were made 

 in the 1953 experiments. 



Before 1954, hemoglobin determinations were made 

 with the Tallquist-Adams hemoglobin scale . This 

 method involves matching a sample of raw blood 

 against a graded color chart . Readings correspond 

 closely to those for human blood. 



In 1954 a Spencer hemoglobin meter was used to 

 make the determinations . When this method is used 

 the blood is hemolyzed before the color comparison is 

 made . Amounts of hemoglobin of salmon blood proved 

 to be approximately one -half that of human blood when 

 the Spencer meter was used . The readings obtained 

 for salmon blood at this laboratory, however, corres- 

 pond closely to those found for trout blood using a 

 similar method of hemoglobin determination . 



With this exception, the methods, equipment, and 

 techniques were identical and comparable to those of 

 previous experiments . 



RESULTS OF THE 1953 EXPERIMENT 



Only the results of the chinook salmon experi- 

 ment wiU be reported since an outbreak of a virus 

 disease in the blueback salmon forced the discontinu- 

 ance of those trials . 



The Chinook diet trials utilized previously tested 

 products in an effort to develop efficient production 

 diets . The feeding trials were conducted for a 24-week 

 period. At the end of the first 12 -week period, all of 

 the diets were altered to include 10 percent of a meal 

 mixture consisting of equal parts of seal meal and 

 distillers solubles. Mortalities were similar in all 

 diets and no deficiency symptoms were evident in any 

 at the end of the experiment. The results of the 1953 

 experiment are summarized in Table 1 . 



The standard meat-viscera mixture was used as 

 the control diet (Diet 1-C> in these trials. Arrow - 

 toothed halibut ( Atheresthes stomias) and salmon vis- 

 cera were fed in combination with beef lung (Diet 2-C), 

 with hog liver and beef lung (Diet 3-C), and with hog 

 liver alone (Diet 4-C). The combination containing 

 only the hog liver (Diet 4-C) produced excellent growth, 

 equalling that of the control and exceeding significantly 

 that of the other two diets containing arrow -toothed 

 halibut (Diet 2-C and 3-C). Neither beef lung nor beef 

 lung and hog liver provided as much growth stimulus 

 as did hog liver alone in the combination . 



Another fish product, hake (Merluccius productus) 

 was fed with beef lung and salmon viscera (Diet 5-C). 

 Significantly less growth was obtained from this diet 

 than for a comparable one containing arrow-toothed 

 halibut (Diet 2-C). 



Two meats, hog liver and beef lung, were com- 

 pared with arrow -toothed halibut when fed in combina- 

 tion diets with 50 percent of salmon viscera as the 

 base . Similar gains resulted from the meat diet (Diet 

 6-C) and the beef lung - arrow -toothed halibut ration 

 (Diet 2-C) . The meat diet produced significantly less 

 growth however than the hog liver - arrow-toothed 

 halibut diet (Diet 4-C). It was concluded from these 

 comparisons that beef lung did not provide as much 

 impetus to the growth rate as did either hog liver or 

 arrow-toothed halibut . 



