Glycosaminoglycan composition of anguilliform and elopiform leptocephali

Abstract

Whole‐body glycosaminoglycan (GAG) composition of leptocephalous larvae was studied in eight eel (Anguilliformes) species, representing five different families (Congridae, Moringuidae, Muraenidae, Nettastomatidae and Ophichthidae) and the bonefish (Elopiformes: Albulidae: Albula vulpes). The extracted GAGs were identified by cellulose acetate electrophoresis, using standard GAGs as a reference, and by their susceptibility to GAG‐degrading enzymes (keratanase, chondroitinase ABC, chondroitinase AC and testicular hyaluronidase). The principal GAG in bonefish larvae was keratan sulphate. However, keratan sulphate was not the main GAG in any of the eel leptocephali studied, althoughit was present in small amounts in most species. The identities of the principal GAGs in eel leptocephali are still unknown, but the most likely possibilities include hyaluronic acid, chondroitin, and chrondroitin sulphate. In addition, a high degree of variability existed in the total amount of GAG that could be extracted from the different eel species and in the electrophoretic migration patterns of the extracted GAGs. Although a basic similarity is thought to exist in the body plan and developmental strategy of all leptocephali, the present results indicate that the GAG composition of the gelatinous body matrix is variable.