20 BULLETIN 378, TJ. S. DEPARTMENT OF AGRICULTURE. 



of fishermen, could well be handled at small by-product plants at- 

 tached to canneries, at the time of the preparation of meal from the 

 waste, or in larger factories devoted entijely to the manufacture of 

 meal. It would seem that in this new field for the use of fish meal 

 for feeding purposes an outlet may have been found for the use of 

 this outcast of the fish tribe and that it can at last be turned into 

 material having a commercial and economic value. 



The addition of this fish in liberal quantities to waste material 

 from canneries, comprising heads, tails, fins, and only a small pro- 

 portion of the meat portion of the fish, would greatly increase the 

 feeding value of the resulting meal. 



Attention should be called to the difference in composition — par- 

 ticularly of the protein material — of fish meal made from whole fish 

 or from waste containing a large portion of the edible part of the 

 fish, and of a fish meal prepared from waste composed entirely of the 

 heads, tails, and fins. In the latter case gelatin or glue derived from 

 the coUogen of the cartilage, bones, and fins, will predominate as the 

 protein constituent, and a meal thus prepared will not have so high 

 a feeding value as one in which the protein derived from the meat or 

 flesh of the fish predominates. 



In instances where waste deficient in the protein constituents of 

 whole fish is available, the dogfish will serve to good advantage as 

 a means of supplying this deficiency and will increase the content 

 of essential tissue-building material. 



GENERAL CONCLUSIONS. 



The universally favorable results obtained in the feeding of fish 

 meal appear to warrant its extended use as a supplementary feeding 

 stuff. 



Laboratory tests have shown that the coefficients of digestibility 

 of the principal constituents of fish meal — the protein and fat — are 

 high, and the feeding experiments have all shown it to be as valuable 

 as many other high-protein concentrates with which it has been 

 compared. 



From the feeding experiments it appears that there has not been 

 just cause for the assumption that the feeding of fish meal of good 

 quality imparts a fishy taint to such products as milk, butter, eggs, 

 and meat. When the meal is fed in proper quantities, as a supple- 

 mentary feed with other feeds, apparently no deleterious effects are 

 noticeable in regard to taint or flavor of fish. There is a possibility 

 that it may impart its flavor to the products of animals or fowls 

 when it is fed to them in too large quantities. Even under these 

 circumstances its use would be warranted, as the feeding of the meal 

 can be discontinued a sufficient length of time during the final fatten- 

 ing period to eliminate any objectionable taint. 



