FISHERY BULLETIN: VOL. 80, NO. 4 



tive nutrient requirements for specific groups of 

 fishes are available. Included are those for trout, 

 salmon, and catfish (National Research Council 

 1973), warmwater fishes such as common carp, 

 Cyprinus carpio, channel catfish (National Re- 

 search Council 1977), and salmonids (National 

 Research Council 1981). Cowey and Sargent 

 (1979) reviewed recent advances in protein, lipid, 

 amino acid, fatty acid, vitamin, and mineral re- 

 quirements of fishes, since their earlier work 

 (Cowey and Sargent 1972). Special emphasis was 

 placed on biochemical pathways in fish. How- 

 ever, only selected vitamin and mineral nutrient 

 requirements of fishes were discussed, and no 

 attempt was made to summarize, in total, the nu- 

 trient requirements of fishes. Also, a brief review 

 of qualitative amino acid, fatty acid, vitamin, 

 and mineral requirements of fishes is available 

 in tabular form (Ketola 1977). 



Currently, there is a paucity of information on 

 nutrient requirements of fry and fingerling 

 stages of coolwater fishes having commercial or 

 recreational value (Ketola 1978; Orme 1978). 

 Such species include the largemouth bass, Mi- 

 cropterus salmoides; smallmouth bass, M. dolo- 

 mieui; yellow perch, Perca flavescens; northern 

 pike, Esox Lucius; muskellunge, E. masquinongy; 

 tiger muskie hybrid (male northern pike X fe- 

 male muskellunge); and walleye, Stizostedion 

 vitreum vitreum. Also, nutrient requirements for 

 striped bass, Morone saxatilis, (a coolwater or 

 warmwater species depending upon the region 

 of occurrence) are lacking except for protein re- 

 quirements of the fingerling stage as a function 

 of dietary lipid content (Millikin in press). 



The present review provides an updated sum- 

 mary of qualitative and quantitative protein, 

 amino acid, lipid, fatty acid, vitamin, and min- 

 eral requirements for all groups of fishes. Nutri- 

 tive values of various feedstuffs, e.g., protein and 

 lipid sources, and their relative contributions to 

 cost-effective feed formulation, are not covered 

 in this review. 



Some topics important in fish nutrition that 

 are not reviewed in the present article are metab- 

 olizable energy values of specific nutrients and 

 feedstuffs for fishes and antinutritional factors 

 often occurring in certain feedstuffs incorpo- 

 rated into commercial fish feeds. Metabolizable 

 energy values of rainbow trout, Salmo gairdneri, 

 have been examined for carbohydrates (Smith 

 1971), proteins (National Research Council 1981), 

 and feedstuffs (Smith 1976; Smith et al. 1980; 

 National Research Council 1981). Also, variabil- 



ity in heat increment as a portion of metabolizable 

 energy resulting from protein, carbohydrate, or 

 lipid ingestion was examined in rainbow trout 

 and Atlantic salmon, S. salar, fingerlings (R. R. 

 Smith etal. 1978). Important antinutritional fac- 

 tors often occurring in commercial-type diets for 

 fishes are antitrypsin activity in soybeans (Sand- 

 holm et al. 1976), mycotoxins in peanut meal and 

 cottonseed meal (Sinnhuber et al. 1977), gossypol 

 in cottonseed meal (Ashley 1972), and cyclopro- 

 penoid fatty acids as cocarcinogens fed simul- 

 taneously with aflatoxins to rainbow trout 

 (Sinnhuber et al. 1968). An informative review of 

 antinutritional factors in fish feeds is included in 

 a review of nutrient requirements of coldwater 

 fishes (National Research Council 1981). 



PROTEIN 



Optimal dietary protein concentrations for 

 fish are dictated by a delicate balance of dietary 

 protein-to-energy ratio, plus protein quality 

 (amino acid balance), and nonprotein energy 

 sources (i.e., amount of fat in relation to carbo- 

 hydrate). Excessive nonprotein energy intake 

 resulting from high digestible energy-to-dietary- 

 protein ratios often causes cessation of feeding 

 before sufficient protein is consumed, since in- 

 gestion rate is primarily determined by total 

 available dietary energy content (Page and An- 

 drews 1973). Conversely, slow growth rates may 

 result from low nonprotein energy intake or for- 

 mula diets may simply be less cost-effective for 

 fish farming purposes. Dietary protein in excess 

 of that required for growth is often utilized for 

 energy in fishes (Cowey 1979). For example, in- 

 creased gluconeogenesis was demonstrated, as a 

 result of higher activities of the gluconeogenic 

 enzymes, fructose diphosphate, and phosphoenol- 

 pyruvate carboxykinase, in rainbow trout fed 

 high dietary protein concentrations (Cowey et al. 

 1981b). Finally, dietary amino acid imbalances 

 may result in higher dietary protein concentra- 

 tions than that required for maximal growth as 

 well as antagonisms between some amino acids, 

 such as isoleucine and leucine in chinook salmon, 

 Oncorhynchus tshawytscha, (Chance et al. 1964), 

 isoleucine, leucine, and valine in channel catfish 

 (Robinson et al. 1982), or lysine and arginine in 

 salmonids (Rumsey 3 ). 



3 Gary L. Rumsey, Tunison Laboratory of Fish Nutrition, 

 U.S. Fish and Wildlife Service, Cortland, NY 13045, pers. 

 commun. December 1981. 



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