Dietary ascorbic acid needs of common carp (Cyprinus carpio) larvae

Abstract As some controversy seem to exist regarding the dietary essentiality of ascorbic acid (AA) for larval cyprinids, a study was conducted to determine the dietary AA requirements with first-feeding larvae of common carp. Six semi-purified diets were formulated to contain graded levels (0, 10, 30, 90, 270, 810 mg kg −1 ) of AA supplied as ascorbyl polyphosphate. Triplicate groups of 250 larvae each were fed one of the experimental diets using automatic feed dispensers over the light hours of the day (temperature: 24±1°C; photoperiod 16L:8D). A duplicate group was kept unfed. Survival, body length and weight increments were recorded. At the end of the 21 day trial, samples were withdrawn for analyses of whole body vitamin C content. The results indicate that common carp larvae have a dietary requirement for ascorbic acid. The required level for maximum tissue storage is higher than that needed for survival and maximum growth. Based on growth performance, a dietary requirement of about 45 mg AA equivalent kg −1 was established. Maximal body vitamin C concentration (104–115 μ g g −1 wet weight) was observed in larvae fed 270 mg AA equivalent kg −1 or more.