in a coffee grinder. An analysis of the particle size of a typical 

 batch of ground scales showed that 3 percent were caught on a 20-mesh 

 U. S. Standard screen, 19 percent on a hO-mesh, 36 percent on a 60-mesh, 

 18 percent on a 80-mesh, and 7 percent on a 100-mesh, and that 17 

 percent passed through a 100-mesh screen. 



The moisture, protein (N x 6.25), fat, and ash of representa- 

 tive samples of scales from the various lots showed no great variation. 

 The mean and ranges of moisture content of h lots of scales were Ii.li 

 percent and 1.0-6.9 percent, respectively; of protein content of 11 

 lots, 59.5 percent and 56.6-62.5 percent; of fat content of h lots, 

 O.OOU percent and 0.0-1.0 percent; and of ash content of 5 lots, 38.9 

 percent and 36.1-U3.1 percent. Association of Official Agricultural 

 Chemists (1955) methods of analyses were used. 



No significant differences in the nutritive value of the scale 

 protein were found among lots. The small differences in moisture, 

 protein, fat, and ash contents of the scales probably can be attributed 

 to the nutritional status and age of the fish from which the scales were 

 collected (195U). 



EXPERIMENTAL 



Postweaning rats were fed diets containing a total of 9 

 percent protein from pollock fish scales (PFS) or a protein supplement 

 of 3 parts casein and 1 part lactalbumin (CL)in stepwise substitution, 

 on an equal nitrogen basis, of the PFS protein, namely, 2.25, U.50, 

 and 6.75 percent. In addition, the CL was also fed alone at these 

 three levels of protein, as well as at the 9 percent level. 



The basal diet had the following composition: lard, 8; cod- 

 liver oil, 2; salt mixture U.S. P. XIV, No. 2, for vitamin-A bioassay, 

 h; and dextrin, 86 parts by weight. To every 100 g. of the basal 

 diet were added 100 mg. of choline chloride, 15 mg. of alpha tocopherol, 

 and 75 mg. of the following vitamin mixture: thiamine HC1, 1; riboflavin, 

 2; pyridoxine, 1; Ca pantothenate, 10; nicotinamide, 10; inositol, 5; 

 para-aminobenzoic acid, 30; biotin, 0.05; folic acid, 0.2; menadione, 

 lii.2; and ascorbic acid, 2 parts by weight. Vitamin B, „ was supplied 

 to the rats by adding 0.2 ml. of a 0.005 percent aqueous solution to 

 individual 250 ml. water bottles every time they were refilled. The 

 ground PFS and CL were incorporated into this basal diet at the expense 

 of dextrin. 



Four highly inbred black-hooded rats, two males and two 

 females, were allotted to each group. The males were allotted at 

 initial live weights of k9 to 53 and the females at I4.8 to 50 g. 

 Litter-mates were randomly distributed among the various groups, but 

 never more than one to any single group. 



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