Ascorbic acid metabolism in fish: is there a maternal effect on the progeny?

Abstract

High maternal ascorbic acid intakes have been shown to ‘condition’ the ascorbic acid requirement of guinea pig offspring. To examine whether a similar effect exists in fish, and what the relative importance of both maternal and offspring ascorbic acid intake is on offspring performance, rainbow trout offspring from females fed high (360 mg kg −1) or ascorbic acid free (0 mg kg −1) diets were maintained on both a high (500 mg kg −1) or marginal (20 mg kg −1) ascorbic acid diet. A high ascorbic acid status of the egg protected hatched fry against increased mortality due to a marginal ascorbic acid intake. Mortality of high ascorbic acid offspring was not affected by the dietary ascorbic acid level until after 18 weeks of initiation of exogenous feeding. However, the marginal diet did result in a significantly lower individual weight starting at Week 7 (final body weight: 2.5 ± 0.4 g, marginal ascorbic acid and 4.8 ± 0.6 g, high ascorbic acid intake). Ascorbic acid deficient offspring fed a marginal ascorbic acid diet showed continuously high mortalities, reaching 92.3 ± 1.9% after 15 weeks. Feeding the high ascorbic acid diet to the ascorbic acid deficient offspring led to significant growth recoveries. Final individual fish weight was not significantly different between the ascorbic acid deficient or the high ascorbic acid offspring fed a high ascorbic acid diet. Survival of both groups fed a high ascorbic acid diet were identical from Week 7 onwards. However, the initially higher mortality in the low ascorbic acid offspring resulted in a significantly higher (71.1 ± 2.2% vs 59.6 ± 6.4%) cumulative mortality. Experiments with radiolabeled ascorbic acid did not reveal significant differences in ascorbic acid conservation after 3 months of feeding.