FISHERY BULLETIN: VOL. 80, NO. 4 



symptoms of cholecalciferol deficiency included 

 decreased weight gain and feed efficiency, 

 marked increase in plasma triiodothyronine (T3) 

 levels, lethargy, anorexia, increased lipid con- 

 tent of white muscle and liver, and clinical signs 

 of tetany. Further study of cholecalciferol defi- 

 ciency in rainbow trout indicated occurrence of 

 tetany of the epaxial musculature (white muscle 

 fibers) and changes in muscle ultrastructure, 

 while red muscle fibers constituting the lateral 

 line musculature appeared to be normal (George 

 et al. 1979). These changes were interpreted as 

 being indicative of disruption of calcium homeo- 

 stasis. Bone ash, calcium and phosphorus, alka- 

 line phosphatase, plasma calcium, and plasma 

 magnesium were similar in rainbow trout fed 

 either 1,000 IU cholecalciferol/kg dry diet or 0% 

 cholecalciferol. Possibly, feeding dietary chole- 

 calciferol concentrations >1,000 IU/kg to rain- 

 bow trout fingerlings would have influenced cal- 

 cium, phosphorus, or magnesium content of bone 

 or plasma. Plasma T3 concentrations of rainbow 

 trout were unaffected by calcium supplementa- 

 tion of vitamin D-deficient diets and plasma and 

 skeletal calcium levels were unaffected by a lim- 

 ited range of dietary vitamin D content (0 to 

 1,000 IU cholecalciferol/kg dry diet) (Leather- 

 land et al. 1980). 



Relative efficacy of dietary ergocalciferol com- 

 pared with dietary cholecalciferol was examined 

 in channel catfish fingerlings (Andrews et al. 

 1980) and rainbow trout fingerlings (Barnett et 

 al. 1979b; Leatherland et al. 1980). Dietary con- 

 centrations of 1,000 IU/kg or less promoted simi- 

 lar growth rates when identical amounts of ergo- 

 calciferol and cholecalciferol were fed to channel 

 catfish. Comparison of identical dietary concen- 

 trations of cholecalciferol and ergocalciferol 

 above 1,000 IU/kg (2,000 to 20,000 IU/kg) re- 

 sulted in greater weight gain of fingerlings fed 

 cholecalciferol. Based upon weight gain, channel 

 catfish fingerlings (initial mean weight = 2.3 g) 

 require dietary cholecalciferol at greater concen- 

 trations than 1,000 IU/kg dry diet, but <4,000 

 IU/kg dry diet (Andrews et al. 1980). Slightly 

 larger channel catfish (initial mean weight = 

 6.0 g) require dietary cholecalciferol at greater 

 concentrations than 1,000 IU/kg dry diet, but 

 <2,000 IU/kg dry diet. Hypervitaminosis oc- 

 curred in channel catfish fed 50,000 IU/kg of 

 ergocalciferol or cholecalciferol as evidenced by 

 reduced weight gain and feed efficiency. How- 

 ever, vertebral bone ash was not affected by vari- 

 ous dietary ergocalciferol or cholecalciferol con- 



centrations. Leatherland et al. (1980) reported 

 that an inverse relationship between T3, a growth 

 stimulating hormone, and dietary vitamin D 

 concentration (cholecalciferol or ergocalciferol) 

 existed in rainbow trout fingerlings. They specu- 

 lated that hypersecretion of T3 in fish fed vitamin 

 D-deficient diets may be a compensatory re- 

 sponse. Cholecalciferol concentrations of 200 or 

 800 IU/kg promoted slightly better growth of 

 rainbow trout than identical concentrations of 

 ergocalciferol (200 or 800 IU/kg). Also, 800 IU of 

 cholecalciferol/kg was the only dietary vitamin 

 D concentration which significantly reduced T3 

 concentrations of fish compared with those fed a 

 vitamin D-deficient diet. Barnett et al. (1979b) 

 reported that rainbow trout fingerlings require 

 between 1,600 and 2,400 IU of cholecalciferol/kg 

 dry diet and that cholecalciferol is three times 

 more effective than ergocalciferol in promoting 

 weight gain. 



Vitamin E 



Vitamin E has been established as an essential 

 dietary component for chinook salmon (Woodall 

 et al. 1964), brown trout (Poston 1965), channel 

 catfish (Dupree 1969b; Murai and Andrews 

 1974), Atlantic salmon (Poston et al. 1976), com- 

 mon carp (Watanabe et al. 1970a; Watanabe and 

 Takashima 1977), and rainbow trout (Cowey et 

 al. 1981a). Vitamin E deficiency symptoms in 

 channel catfish include poor growth, reduced 

 food conversion, exudative diathesis, muscular 

 dystrophy, depigmentation, fatty livers, anemia, 

 and atrophy of pancreatic tissue (Murai and An- 

 drews 1974). Dietary supplementation of dl-«- 

 tocopherol (25 to 100 mg/kg) fed to channel cat- 

 fish fingerlings removed all of these deficiency 

 symptoms, whereas an antioxidant, ethoxyquin 

 (125 mg/kg), did not significantly improve 

 hematocrit levels or reduce incidence of muscu- 

 lar dystrophy. Vitamin E deficiency symptoms 

 in chinook salmon included poor growth, exoph- 

 thalmia, ascites, anemia, clubbed gills, epicar- 

 ditis, and ceroid deposition in the spleen (Woodall 

 et al. 1964). Brook trout fingerlings fed vitamin 

 E-deficient diets had reduced growth rates, in- 

 creased mortality, and lower microhematocrit 

 values than did fish fed a diet containing 500 mg 

 of m.-a-tocopherol acetate/kg dry diet (Poston 

 1965). Atlantic salmon fed vitamin E-deficient 

 diets displayed anemia, pale gills, anisocytosis, 

 poikilocytosis, exudative diathesis, dermal 

 depigmentation, muscular dystrophy, and in- 



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