Table 6; — Effect of caloric levels on protein deposition and utilization, 



fat deposition, and mortality 



level, protein deposition was significantly 

 higher in fish from the 2, 350 -caloric diets 

 than in fish from the 2, 000 -calorie diets at the 

 end of 24 weeks. There was no difference in 

 protein utilization. At 12 weeks, the 2,350- 

 calorie diets could not be shown to be superior 

 to the 2,000-calorie diets. While there was no 

 difference at 12 weeks between fish from the 

 2, 000 -and 2, 3 50 -calorie diets at the 2 7. 5 -per- 

 cent protein level, a significant increase in 

 protein deposition and utilization was evident 

 in fish from the 2,350-calorie ration, diet 21, 

 as compared with fish from the 2,000-calorie 

 ration, diet 20, at the end of 24 weeks. A 

 sparing action on the protein requirements at 

 higher caloric levels is indicated. 



The increased caloric intake also had an 

 influence upon mortalities . Mortality rates 

 were significantly lower in the high -calorie 

 rations , diets 7 and 8 , than in the comparable 

 low -calorie ration, diet 6, at the 20 -percent 

 protein level. Fish in diet 12 had a signifi- 

 cantly lower mortality rate than did fish in diet 

 10 at the 25 -percent protein level. Mortalities 

 were attributed to a hypovitaminosis which be- 

 came evident in the low-calorie, low-protein 

 diets at 16 weeks and progressively spread into 

 the high -protein, hig^ -calorie diets until at 

 the end of 24 weeks all of the diets, with the 

 exception of the all -meat control diet, had 

 some fish exhibiting the deficiency syndrome . 



The degree of the hypovitaminosis was correlated 

 with the levels of protein and calories fed, with 

 the low-calorie, low -protein diets affected the 

 most. A sparing action on the vitamin require- 

 ments at higher protein and caloric levels is 

 indicated . 



Fat deposition and protein calorie to 

 energy calorie relation, 12 weeks. - -An increase 

 in caloric intake from 1,650 calories in diet 7 

 to 2,000 calories in diet 8 did not increase pro- 

 tein deposition or efficiency but did increase 

 significantly the fat deposition of fish fed at the 

 20-percent protein intake level. A caloric in- 

 take level of 1,650 calories per kilogram with a 

 protein calorie to energy calorie ratio of 1:1 

 appeared to be near optimum . These results 

 were also similar to those of Combs et al. (1962). 

 An increase in caloric level from 2,000 calories 

 in diet 11 to 2,350 calories in diet 12 did not in- 

 crease fat deposition, nor did it increase protein 

 utilization of the fish fed at the 25-percent level 

 of protein intake. Fish from both diets 11 and 

 12 had significantly higher fat and protein depo- 

 sition than did fish from diet 10 at the 1,650- 

 calorie level. An increase in calories from 

 2,000 in diet 16 to 2,350 in diet 17 did produce 

 a significant increase in the fat deposition in the 

 fish, but it did not increase the protein deposited. 

 Here again a 1:1 ratio of protein calories to 

 energy calories appeared to be optimum . In 

 the 27.5-percent protein diets, an increase in 



