FISHERY BULLETIN: VOL. 80, NO. 4 



diet or 1.8 ng cyanocobalamin/g diet suggested 

 that cyanocobalamin requirements are margi- 

 nal for channel catfish (initial mean weight = 

 7.1 g) over a 24-wk period. However, channel cat- 

 fish fry and early fingerling stages may have 

 demonstrated a cyanocobalamin requirement 

 under similar conditions. 



The effects of feeding folic acid-deficient or 

 folic acid plus vitamin Bi 2 (cyanocobalamin)-defi- 

 cient diets have been examined with brook trout 

 (Phillips 1963) and rohu (John and Mahajan 

 1979). During the time interval between 9 and 15 

 wk of a feeding study, anemia was more pro- 

 nounced in brook trout fed a diet deficient in both 

 vitamin Bi 2 and folic acid than in individuals fed 

 a diet deficient in folic acid only. Lethargy, mus- 

 cular loss, and poor growth rate were accentu- 

 ated in rohu fed a diet concurrently deficient in 

 folic acid and cyanocobalamin, compared with 

 fish fed diets deficient in either folic acid or 

 cyanocobalamin, singly. Megaloblastic anemia 

 occurred in rohu fed a folic acid-deficient diet, a 

 cyanocobalamin-deficient diet, and a diet defi- 

 cient in both vitamins (John and Mahajan 1979). 



Biotin 



Qualitative dietary requirements for biotin 

 have been demonstrated for brook, brown, and 

 lake trout (Phillips and Brockway 1957), chinook 

 salmon (Halver 1957), coho salmon (Coates and 

 Halver 1958), goldfish, Carassius auratus (Tomi- 

 yama and Ohba 1967), common carp (Oginoetal. 

 1970b), Japanese eel (Arai et al. 1972a), channel 

 catfish (Robinson and Lovell 1978), and lake 

 trout (Poston and Page 1982). Biotin deficiency 

 symptoms generally occurring in salmonids in- 

 clude anorexia, poor growth, and depressed liver 

 acetyl CoA carboxylase and pyruvate carbox- 

 ylase (Poston and Page 1982). Biotin deficiency 

 signs include spastic convulsions, fragmentation 

 of erythrocytes, and muscle atrophy in chinook 

 salmon (Halver 1957), depigmentation in chan- 

 nel catfish (Robinson and Lovell 1978), abnormal 

 synthesis of liver fatty acids and high liver glyco- 

 gen content in brook trout (Poston and McCart- 

 ney 1974), pale-colored gills often with a mucous 

 coating, protruding beyond the operculum in 

 rainbow trout (Castledine et al. 1978), and high 

 rates of deposition of glycogen in kidney tubules 

 and short, thick gill lamellae in lake trout (Pos- 

 ton and Page 1982). 



Biotin has been shown to be important in af- 

 fecting growth and acetyl CoA carboxylase ac- 



tivity in fish. Lake trout fingerlings required a 

 minimum of 0.1 mg biotin/kg dry diet for opti- 

 mal growth rate and a minimum of 0.5 mg bio- 

 tin/kg dry diet for optimal swimming stamina 

 (Poston 1976a). Acetyl coenzyme A carboxylase 

 activity has been shown to be fully activated in 

 livers of rainbow trout containing >3.3 ^g bio- 

 tin/g liver (Castledine et al. 1978). Dietary biotin 

 concentrations of 8 mg/kg dry diet enhanced 

 liver pyruvate decarboxylase activity in channel 

 catfish fingerlings (Robinson and Lovell 1978), 

 whereas 6 mg biotin/kg dry diet increased acetyl 

 CoA carboxylase and pyruvate decarboxylase 

 activities in brook trout fingerlings (Poston and 

 McCartney 1974). Common carp fingerlings re- 

 quire 1 mg biotin/kg dry diet for maximal weight 

 gain and biotin liver content (Ogino et al. 1970b). 

 Since biotin-containing lipogenic and gluco- 

 neogenic enzymes or both may have low activity 

 in biotin-deficient trout, increased liver glycogen 

 concentrations and altered liver fatty acid com- 

 positions may result (Poston and McCartney 

 1974; Poston 1976a). High concentrations of liver 

 glycogen were reported in biotin-deficient lake 

 trout (Poston 1976a; Poston and Page 1982) 

 and rainbow trout (Castledine et al. 1978). 

 Altered liver fatty acid composition occurred in 

 biotin-deficient brook trout (Poston and McCart- 

 ney 1974) and rainbow trout (Castledine et al. 

 1978). Liver lipid concentrations did not vary be- 

 tween channel catfish fed 0% or 8 mg biotin/kg 

 dry diet over a 22-wk period (Robinson and Lovell 

 1978). Biotin-deficient diets resulted in larger 

 liver size in brook trout compared with individ- 

 uals fed sufficient dietary biotin (6 mg/kg dry 

 diet) (Poston and McCartney 1974), whereas the 

 presence (8 mg/kg dry diet) or absence of dietary 

 biotin did not affect liver size in channel catfish 

 (Robinson and Lovell 1978). 



Inositol 



Qualitative requirements for inositol have 

 been reported for rainbow trout (McLaren et al. 

 1947), brook, brown, and rainbow trout (Phillips 

 and Brockway 1957), chinook salmon (Halver 

 1957), coho salmon (Coates and Halver 1958), 

 common carp (Aoe and Masuda 1967), Japanese 

 eel (Arai et al. 1972a), and red sea bream (Yone 

 1975). General inositol deficiency symptoms in- 

 clude poor feed digestibility and utilization, 

 anorexia, reduced growth, and distended abdo- 

 mens (Halver 1972a). Skin lesions occurred in 

 common carp fed inositol-deficient diets and in- 



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