Dietary Vitamin C Requirement of Hybrid Striped Bass Morone chrysops♀× M. saxatilis ♂

Abstract

AbstractA feeding trial was conducted to determine the dietary vitamin C requirement of juvenile hybrid striped bass Morone chrysops × M. saxatilis. Fish were fed a semi‐purified basal diet with 40% crude protein and an energy to protein ratio of 8 kcal/g for a conditioning period of 2 wk. This diet which was not supplemented with vitamin C contained approximately 6‐mg vitamin C/kg. Following conditioning, fish (approximately 0.55 g initial weight) were stocked as groups of 20 in 38‐L aquaria and fed the basal diet and experimental diets supplemented with 10, 20, 30, 45, 60, 75, or 150‐mg vitamin C/kg as ascorbate polyphosphate for a period of 10 wk. Fish fed the basal diet and the diet supplemented with 10‐mg vitamin C/kg exhibited signs of vitamin C deficiency including suppressed weight gain, reduced plasma and liver ascorbic acid levels, and abnormalities in isthmus cartilage formation. Plasma and liver ascorbic acid levels generally reflected dietary supplementation with the lowest levels occurring in fish fed the basal diet and higher levels in fish fed the supplemented diets. The minimum dietary requirement (±SE) based on non‐linear least squares regression analysis of weight gain was 22 (±6) mg vitamin C/kg diet.