According to Ltehring, grains — on account of their high mineral contents — aid in the 

 fertilization of the ponds via the feces of fish. Their food quotient is from i* to 6, 

 In difference to maize, these grains do not react upon the taste of the flesh. The 

 possibilities of their uses is a question of price. 



Barley and barley middlings have an especially favorable food quotient and are widely 

 used — notwithstanding their hard shells — for carp broodlings and younger carp. 



In Thuringia, according to Kamprath . barley is served out to larger carp (after soakini 

 it in tepid water for 12 hours) in the belief that it produces a finer and tastier flesh, 



Flours^-bran, brewers grain and distiller's wash from rye, barley, oats, wheat, rice 

 and maize can be given to carp and tench without further preparation. The food quotient 

 is from 4- to 6, at times below U» Very fine flours like rice flour, rice bran (1930 about 

 $1,62 per 100 pounds) obtained from polishing rice grains and containing according to law 

 not less than 22 percent of protein and fat, can only be used profitably in the food cycle 

 by feeding in lumps made by water admixture or after hot preparation or in briquette form. 

 For carps, the fine flour form is the most unfavorable, often giving food quotients of 10 

 and over in the case of rice feed flour, but vdth proper distribution only 4-5. AH 

 flours, especially rye flour, rough wheat bran and rice feed-flour are important as 

 binders for trout food and are then added to the main foodstuffs (meat, fish) in amounts 

 up to 35 percent. Rice feed-flour is especially noted for a high protein rate, a high 

 rate in vitamin B and is normally free iS-om chaff (chaff contents of over 13 percent must 

 be Indicated), Haempel . on account of its high vitamin rate, considers it especially 

 valiiable as binder in trout culture, 



Vlheat bran, according to the experiments of Gas-chott and Probst and from all practical 

 experiences also rates high as a by-product for trout food, 



Waste products from oil extractions (sunflower seeds, pumpkin seeds, palm kernels) 

 can be similarly used as maize but impart a still stronger taste to the flesh than maize. 

 They are low in vitamins. Food quotient about from 5 to 6 (according to Klee), They may 

 be fed to yearling and two year carps, but must not be given shortly before the fishing 

 out time. 



Potatoes are not very well suited for carp and tench. Their food quotient is 20, 

 even 30 or more. They are usable to some extent only when cooked and mixed with animal 

 flours. Steamed mashed potatoes — and dry potato pulp in amounts of from 10 to 20 percent — 

 make a good binder with sea fish or with meat for trout food, 



Waste cookies and other bakery wastes may be used for feeding. This kind of food 

 cooky, which was prepared with cacao butter contained 6.33 percent crude fat, of which 

 3,34 percent consisted of free fatty acids. The air dry feces of carps, feed in the 

 winter pond, contained 32,9 percent crude fat of which 42.1 percent consisted of free 

 fatty acids (calculated as oleic acid). Accordingly, the fat of the cake seens to have 

 been hardly digestible, at least in the winter. Waffle waste in Wielenbach 1931 had a 

 very good reaction, the food quotient amounted to only 3.1. 



Beech and poplar sawdust is used as a cheap binder and "ballast" for fresh trout 

 food. It lowers the dangers of indigestion and of losses quite perceptibly (demoll), 

 A food mixture of 75 percent of salt water fish and of 25 percent of sawdust had a food 

 quotient of 4.9, salt water fish alone had one of 5,3, AH too large doses of sawdust 

 are detrimental, though, sawdust added to fattening food of cattle lowers the effects 

 of these foodstuffs (Kellner). 



Dry yeast has of late been introduced into trout culture in order to enrich the 

 vitamin content. Some fishbreeders consider it a prophylatic against lipoidal degener- 

 ation of the liver. Gaschott and Probst, experimenting with exposures of dry yeast to 

 violet rays have demonstrated that a more than 4 percent addition to trout foods does 

 not repay. Dry yeast (Genovitan) is composed of 50 percent protein, 2 percent of fat, 

 24 percent of carbohydrates and 3 percent of phosphatic salts. 



138 



