A REVIEW OF THE CHEMICAL AND NUTRITIVE PROPERTIES OF 



CONDENSED FISH SOLUBLES 



Joseph Scares, Jr.,' David Miller,' Susan Cuppett,^' and Paul Bauersfeld, Jr.'' 



ABSTRACT 



This paper attempts to review some of the pertinent data available on the chemical and 

 nutritive properties of condensed fish solubles with special reference to condensed men- 

 haden solubles. Information concerning other kinds of fish solubles from various published 

 sources is tabulated for comparison. The results of three analytical and three biological 

 studies of menhaden solubles are reported. 



Data show that menhaden stickwater contains an average of 4.8% protein, 93.4% water, 

 and about 1.25% lipid. The solids are concentrated about seven times by vacuum evap- 

 oration to yield condensed solubles. Data show that this product contains about 32% 

 protein, 49% water, and 11% fat. Additional data are presented on the content of amino 

 acids in fish solubles, which show that the indispensable amino acid tryptophan is rel- 

 atively low and. on the content of essential inorganic elements which are shown to be 

 present, generally in acceptable levels. Fish solubles are shown to be rich sources of 

 choline, niacin, pantothenic acid, riboflavin, biotin, and vitamin Bj2. 



An experiment with broiler chicks showed that the average metabolizable energy con- 

 tent of 10 samples of condensed menhaden solubles from commercial plants located along 

 the Atlantic and Gulf coasts was 2.03 kcal/g on an "as fed" basis. Average protein and 

 fat digestibility was 89 and 57%, respectively. 



Further studies with broiler chicks showed that significant unidentified growth factor 

 responses could be obtained when 5% menhaden solubles was used in diets. A significant 

 response was obtained even when the chicks were reared in a gnotobiotic environment. 

 This indicates that the presence of bacteria is not necessary for solubles to produce a 

 growth response in chicks. 



This review attempts to discuss some of the more 

 pertinent recent published and unpublished data 

 available on the chemical and nutritive proper- 

 ties of condensed fish solubles. For many years 

 stickwater was considered as a waste effluent 

 and was not used in animal feeds or in other 

 manufacturing processes. However, with the 

 postwar surge in production of fish meal, this 

 by-product began to be recognized for its nu- 

 tritional value. In the presynthetic nutrient era, 

 condensed fish solubles was recognized as an out- 

 standing source of B vitamins and minerals for 

 poultry and swine. Later, solubles was the prin- 



' College Park Fishery Products Technology Labora- 

 tory, National Marine Fisheries Service, NOAA; present 

 address: Department of Poultry Science, University 

 of Maryland, College Park, MD 20740. 



" College Park Fishery Products Technology Labora- 

 tory National Marine Fisheries Service, NOAA, College 

 Park, MD 20740. 



ciple source of the "animal protein factor" or 

 vitamin B12. Today we still consider condensed 

 fish solubles to be valuable for these purposes, 

 but now more emphasis is put on its unidentified 

 growth factor content. 



There are various sources and kinds of con- 

 densed fish solubles available in the United 

 States. However, about 80 9r of the solubles 

 used in this country are produced by the men- 

 haden reduction industry located along the At- 

 lantic and Gulf coasts. Since 1963, the quantity 

 of solubles available for animal feedstuff sup- 

 plementation in the United States has averaged 

 about 90,000 tons annually. 



However, because of the difficulty in handling, 

 storing, and mixing the viscous condensed fish 

 solubles, a considerable quantity of this product 

 is dehydrated on a carrier to produce a free- 

 flowing dry product. One such product is "full 



Manuscript accepted September 1972. 



FISHERY BULLETIN: VOL. 71, NO. 1, 1973. 



255 



