MII.I.IKIN: NUTRIENT REQUIREMENTS OK KISIIKS 



provides additional useful information for esti- 

 mating quantitative vitamin requirements. 

 Channel catfish fingerlings require a minimal 

 dietary thiamine concentration of 1 mg/kg dry 

 diet based upon maximal weight gain, feed effi- 

 ciency, and prevention of thiamine deficiency 

 symptoms such as anorexia, poor growth, dark 

 coloration, and higher mortality (Murai and 

 Andrews 1978a). Hematocrit values of channel 

 catfish were unaffected by dietary thiamine con- 

 centrations ranging from 0.1 to 20.1 mg/kg dry 

 diet. 



It is unknown why channel catfish and com- 

 mon carp require lower dietary concentrations 

 of thiamine compared with salmonids. Omnivo- 

 rous fish would seemingly require higher 

 amounts of thiamine for oxidative decarboxyla- 

 tion of pyruvate and the transketolase reaction of 

 the pentose phosphate shunt, due to the ability of 

 herbivores and omnivores to metabolize higher 

 dietary carbohydrate concentrations than car- 

 nivorous fish such as salmonids (Murai and An- 

 drews 1978a). 



Riboflavin 



Dietary essentiality for riboflavin has been re- 

 ported for rainbow trout (McLaren et al. 1947), 

 brook, brown, and lake trout (Phillips and Brock- 

 way 1957), chinook salmon (Halver 1957), Atlan- 

 tic salmon (Phillips 1959a), channel catfish (Du- 

 pree 1966), common carp ( Aoe et al. 1967a; Ogino 

 1967), rainbow trout (Kitamura et al. 1967a; 

 Poston et al. 1977; L. Takeuchi et al. 1980), Japa- 

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

 (Yone 1975). Rainbow trout (mean initial weight 

 = 5.9 g) fed riboflavin-deficient diets developed 

 bilateral corneal and lenticular lesions after 11 

 and 15 wk of the experimental period (Poston et 

 al. 1977). Further evaluations of cataract forma- 

 tions induced from riboflavin deficiency in rain- 

 bow trout fingerlings confirmed no retinal dam- 

 age according to histopathological examinations 

 (Hughes et al. 1981a). Fin necrosis, snout erosion, 

 and spinal deformation also occurred in ribo- 

 flavin-deficient rainbow trout (Poston et al. 

 1977). In a separate study, rainbow trout finger- 

 lings ( initial mean weight = 1.5 g) fed riboflavin- 

 deficient diets displayed anorexia, poor growth, 

 high mortality rate, lesion of fins, and cataract 

 formation during an 8-wk study (L. Takeuchi et 

 al. 1980). Common carp fingerlings fed ribofla- 

 vin-deficient diets showed anorexia, poor growth, 

 high mortality rate, and hemorrhage of skin and 



fins (L. Takeuchi et al. 1980). Murai and Andrews 

 (1978b) reported 100% occurrence of "short body 

 dwarfism" due to shortening of individual verte- 

 brae in riboflavin-deficient channel catfish after 

 20 wk. These authors speculated that abnormal 

 vertebral growth may be related to hypothyroid- 

 ism which in turn may be caused by riboflavin 

 deficiency. 



Quantitative riboflavin requirements have 

 been determined for common carp, rainbow 

 trout, and channel catfish. In several different 

 studies, riboflavin requirements of carp finger- 

 lings apparently declined with increasing fish 

 size based on growth rate and liver riboflavin 

 content. Common carp fingerlings with an initial 

 mean weight equalling 1.5 g required 20 mg 

 riboflavin/kg dry diet over a 6-wk period (Aoe et 

 al. 1967a). Slightly larger carp fingerlings (ini- 

 tial mean weight = 2.8 g) required 10 mg ribofla- 

 vin/kg dry diet over a 6-wk period (Ogino 1967), 

 whereas individuals with an initial mean weight 

 equalling 3.4 g required 5 to 7 mg riboflavin/kg 

 dry diet (L. Takeuchi et al. 1980). Rainbow trout 

 with an initial mean weight of 7 g required 12.2 

 mg riboflavin/kg for maximal growth, whereas 

 18.2 mg riboflavin/kg were required for satura- 

 tion of head and posterior kidney tissue (Wood- 

 ward 1982). However, larger rainbow trout fin- 

 gerlings (initial mean weight = 11.2 g) required 



3 mg riboflavin/kg dry diet according to growth, 

 food conversion, and mean erythrocyte glutathi- 

 one reductase activity coefficient or 12 mg ribo- 

 flavin/kg dry diet for maximal liver riboflavin 

 content (Hughes et al. 1981b). Rainbow trout 

 fingerlings (initial mean weight = 1.5 g) required 



4 mg riboflavin/kg dry diet based upon growth 

 rate and feed efficiency and 6 mg riboflavin/kg 

 dry diet based on liver riboflavin content (L. 

 Takeuchi et al. 1980). Channel catfish fingerlings 

 require 9 mg riboflavin/kg dry diet for maximal 

 growth and 3 mg riboflavin/kg dry diet to pre- 

 vent occurrence of short body dwarfism (Murai 

 and Andrews 1978b). 



Pyridoxine 



Dietary essentiality of pyridoxine has been re- 

 ported for rainbow trout (McLaren et al. 1947), 

 brook, brown, and lake trout (Phillips and Brock- 

 way 1957), chinook salmon (Halver 1957), Atlan- 

 tic salmon (Phillips 1959a), coho salmon (Coates 

 and Halver 1958), common carp (Ogino 1965), 

 channel catfish (Dupree 1966), rainbow trout 

 (Kitamura et al. 1967a), yellowtail (Sakaguchi et 



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