Dynamics of collagen indicating amino acids, in embryos and larvae of sea bass ( Dicentrarchus labrax) and gilthead sea bream ( Sparus aurata), originated from broodstocks fed with different vitamin C content in the diet

Abstract

The dynamics of hydroxyproline–proline (HYP–PRO) and hydroxylysine (HYL), as amino acids indicators of collagen, has been studied in fertilised eggs, embryos and fasting larvae of sea bass ( Dicentrarchus labrax L.) and gilthead sea bream ( Sparus aurata L.). Broodstocks of the two species were fed every second day with two types of diets: one containing sufficient ascorbate for a normal growth and the other with an extra addition of a very high dose (2000 mg kg −1 feed) of coated l-ascorbic acid (AA). The collagen hydroxylation expressed as the HYP-PRO ratio, hydroxylysine (HYL1 and HYL2) and total ascorbate (TAA) concentrations were analysed in several embryonic and larvae developmental stages. TAA concentrations in the newly fertilised eggs and larvae resulted significantly higher in offspring of broodstocks fed an additional dose of 2000 mg AA/kg feed than in those fed a normal diet ( P<0.05 or P<0.01). The differences in HYP–PRO ratio values between the groups fed AA-supplemented and unsupplemented diets, were significant for all the analysed stages, being higher in the supplemented groups. The values of HYL were higher, although not always significantly, for all the analysed stages, in offspring of the supplemented group, compared to the offspring of the unsupplemented one. In conclusion, a vitamin C dose of 2000 mg kg −1 feed, delivered every second day to sea bass and gilthead sea bream broodstock, increases the collagen synthesis in embryos and fasting larvae, in comparison with a diet containing vitamin C at the recommended concentration for growth.