The 1962 feeding trials demonstrated the 

 practicability of the meal combination, the 

 effect of three protein levels on growth, and 

 the effect of energy calorie supplementation 

 on protein utilization. It was also demonstra- 

 ted that an all-meal diet was as successful as 

 comparable meat -supplemented diets and that 

 \dtamin supplementation could not be shown to 

 be of any measurable value when fed in diets 

 containing a meat supplement . 



Roger E. Burrows, Bobby D. Combs, and 

 Dr. Wilton W. Heinemann assisted in design 

 of the experiment and interpretation of results; 

 Joseph W . Elliott made the chemical analysis 

 of the fish and diet components . 



METHODS AND TECHNIQUES 



The methods, techniques, and equipment 

 used in the 1962 feeding trials were similar to 

 those used in previous trials at this laboratory. 

 Samples of fish weighing 500 grams were 

 drawn from a homogeneous population and 

 placed randomly in paired tanks . At bi- 

 •weekly intervals the fish in each tank were 

 weighed and from these data the amount of 

 food fed was calculated from feeding charts 

 developed for chinook salmon. The food was 

 ricer-fed with the frequency of feeding de- 

 pendent on the time required for consumption. 



The chemical composition of feeds wa s 

 used as the basis for diet formulation, with 

 caloric levels calculated on the basis of 

 available calories as developed by Phi Hips 

 and Brockway (1959). The chemical composi- 

 tion of the fish, as determined by proximate 

 analysis, was the criterion used for analyzing 

 the results of the experiments . Protein depo- 

 sition was used as the measure of growth in- 

 stead of total gain in wei^t. Protein utili- 

 zation, a measure of the efficiency of a diet 

 for growth production, was calculated by 

 dividing the amount of protein fed by the 

 amount of protein deposited in the fish . At 

 the conclusion of the feeding trials, the data 

 were analyzed statistically by use of analysis 

 of variance for paired experiments as out- 

 lined by Snedecor (1956). 



The techniques employed are similar to 

 those used in previous feeding trials as de- 

 scribed by Burrows et al. (1951; 1952) and by 

 Combs et al . (1962) with the following exceptions : 



1. The difficulties encountered in the 1961 

 experiments (Combs et al., 1962) were elimi- 

 nated by the use of pathogen-free well water at 

 a constant temperature of 53* P. and the housing 

 of the experimental tanks within the laboratory 

 to remove the possibility of diet supplementation 

 with natural foods . 



2 . The original control diet was the Entiat 

 production diet which had been fed on a produc - 

 tion basis at Entiat, Washington, for several 

 years and at Longview during 196 1 with excel - 

 lent results , but always on an increasing water 

 temperature. This diet was marginal in vitamin 

 content and when fed on a constant water temper- 

 ature where the intake of the fish was much 

 lower than at a rising temperature , a severe 

 anemic condition became apparent at the end of 

 eight weeks which resulted in the termination of 

 this group of fish as a control. A new group of 

 fish was substituted and placed on the Leaven- 

 worth production diet with satisfactory results . 

 Table 1 gives the basic components of the diets 

 and the vitamin supplement fed. The ingredients 

 of the basic mixtures and their proximate analy- 

 sis are shown in table lA. 



3. The feeding trials were carried on for 

 a 24 -week period. Data included in this report 

 were compiled at the end of 12 weeks and at the 

 end of 24 weeks . 



4 . Stamina tests were run on fish from 

 each diet at the conclusion of the experiments, 

 utilizing the stamina -tunnel device developed at 

 this laboratory. Two 100-fish samples were 

 tested from each diet and a performance index 

 calculated. 



5. Vitamin injection studies were conducted 

 after the regular feeding experiments in an attempt 

 to determine the cause of a nutritional deficiency 

 which became apparent in all the experimental diets 

 after 16 weeks of feeding. Affected fish from low- 

 calorie, low -protein diets were selected to be used 

 for the studies . 



