Effects of dietary cholecalciferol and ergocalciferol on catfish

In separate feeding trials, channel catfish fingerlings were fed 0, 1000, 4000, 8000, 20,000, 50,000, and 0, 500, 1000, 2000, 4000, 8000 I.U./kg diet of cholecalciferol and ergocalciferol for 28 weeks. The supplemental requirement for maximal growth was between 1000 and 4000 I.U. of supplemental cholecalciferol/kg diet. At supplemental levels of 1000 I.U./kg diet or less, the growth responses to ergocalciferol were equal to those obtained from equivalent levels of cholecalciferol. However, at higher supplemental levels of ergocalciferol, the weight gains were significantly less than those obtained from 2000 to 20,000 I.U./kg of cholecalciferol. Weight gains were significantly reduced when 50,000 I.U./kg of cholecalciferol were fed. Vertebrae bone ash values were not affected by dietary vitamin D levels. Reduced weight gains and feed efficiency were the only signs of vitamin D deficiency or hypervitaminosis D.