cleanliness and freshness are more important than the amount of foodstuff content. Care 

 is very advisable, and doubtful flours should be analyzed, as bad fish flours most fre- 

 quently cause intentinal inflammations. 



Fish flours belong to the most important foods. Special success is gained in the 

 feeding of carp brood and yearlings by adding 23 to 35 percent of fish flour to the main 

 food. These successes with carps are partly traceable to the high vitamin A content, 

 which, however, disappears in overheated flours. 



I was told by one certain fishbreeder that from long experience he has come to the 

 conclusion that mixing the main foodstuffs with fish flour will prevent "white spot" 

 (IchthyophthixiBsis). Since water and soil of this particular hatchery are very poor in 

 lime, it is not at all in^Dossible that the high content of calcium phosphate in fish 

 flour, in combination with the high content of content of animal protein and of vitamin 

 A really do give good results in this particular case. 



According to Haempel . it was Aulde wl-io found that lack of calcium (lime) counter- 

 acts the effects of vitamine A, while on the other hand the storage of calcium (lime) 

 depends upon same. 



In trout culture, fish flour is used as a supplementary food and in emergencies 

 even as main food, to which some vegetable flour is then a'ded. Food quotient — as far 

 as known as yet — is from 1.5 to 3 (for carp and trout). 



Roe of salt water fish is often offered as foodstuff for trout fingerlings — especial- 

 ly between Jani;iaiy and April — but is not all too highly valued by fishbreeders. It is 

 mostly far too salty, even if labeled "mildly salt^f" . 



Fresh Freshwater Fish are exceedingly valuable food for trout growing. Ever increas- 

 ing numbers of fisheries endeavor to get a supply of cheap and otherwise not valuable 

 bleak fish, red eyes, roaches, blays, etc. Unfortunately deliveries can not be maintained 

 steadily throughout the year. In exact aquarium feeding experiments on 10 to 100 gram 

 rainbow trout on a diet of "v;hite fish", Cornelius found at 10° an average food quotient 

 of 2.9, and at 17° one of 6. Fish flour from freshwater fish, which are not marketable on 

 account of too low prices, is now being manufactured (especially in Hungary), and naturallj 

 it may be used under the same conditions as flour fro;a sea fish. 



Fresh meat from warmblooded animals . The production of many trout fisheries in 

 Northern and Southerri GermAny depends preponderantly on the feeding with this meat. This 

 includes beef and horse meat, which fish growers buy directly, meat and organs from 

 slaughterhouse waste ($1,52 per 100 pounds in 1930) and meat from flaying establishments. 

 Unfortunately in times of stress available amounts are always smaller. The shortage of 

 available meat is increasing also on account of stricter veterinary police rules. V/liere 

 veterinary police restrictions are not in effect, it must be remarked or rather advised 

 to cook the meat and organs (in many localities much lung is fed) of tubercular of other- 

 wise diseased animals before feeding it, on account of transmission danger, unless already 

 cooked meat has been purchased. Regarding the preparation, methods were discussed earlier. 

 The total requirement of food flesh is often very considerable, A fishery wliich produces 

 10,000 pounds of trout a year, requires in the summer a whole beef or horse daily. 



But while feeding of these materials is of sheer necessity, they are inferior to 

 salt water fish and in every respect. They also impart a bad taste to the flesh of trout 

 and their mixing with by-products is absolutely necessary in order to avoid intestinal 

 disorders in trout. Spleen and yeast (both rich in vitamines) should also be added to the 

 flesh from warm-blooded animals. Especially v/hen cooking has destroyed vitamins and made 

 the protein more indigestible. Feeding with salt water fish, at least once a week will 

 somewhat improve the otht-rwise bad taste of trout. I recommend to stop altogether with 

 feeding meat from warmblooded animals 4- to 5 weeks before bringing the trout to market. 



The food quotient varies greatly. The quotient of very sinewy pork without by-food 

 in the case of pond feeding — hovers around from L,.b to 5.7. The average is about between 

 5 and 8. 



UO 



