Histopathological observations during larval rearing of common dentex Dentex dentex L. (Sparidae)

Histological observations in cultured common dentex Dentex dentex larvae ar e described from days 1 to 36 after hatching. No alterations were found thr oughout the lecitotrophic period. Following subsequent experimental starvat ion, larvae showed atrophy of the digestive structures, pancreatic degenera tion and lack of supranuclear vacuoles in the hindgut. During transition fr om endogenous to exogenous feeding, 30% of 7- and 8-day-old larvae and 11% of 9-day-old larvae exhibited histological alterations similar to those des cribed in starved individuals, regardless of the level of rotifer enrichmen t. During the Artemia feeding period, intestinal steatosis was a common fea ture, mainly from day 30 onwards. Swimbladder non-inflation rates ranged fr om 12% to 77%. By day 17, the batch of larvae showing the highest percentag e of non-inflation exhibited the lowest growth performance. Histopathologic al alterations associated with bacterial agents were described only occasio nally. No parasites were found in any of the specimens examined. It is sugg ested that nutritional factors, rather than infectious agents, are responsi ble for the high mortality encountered in cultured dentex larvae. (C) 2001 Elsevier Science B.V. All rights reserved.