USE OF FREEZE-DRIED MICROALGAE FOR REARING GILTHEAD SEABREAM, SPARUS-AURATA, LARVAE - I - GROWTH, HISTOLOGY AND WATER-QUALITY

Four gilthead seabream larval feeding treatments [(A) larvae fed rotif ers cultivated with freeze-dried microalgae and daily addition to the larval tank of freeze-dried microalgae; (B) larvae fed rotifers cultiv ated with freeze-dried microalgae and daily addition to the larval tan k of live microalgae; (C) larvae fed rotifers cultivated with freeze-d ried microalgae and without addition of microalgae to the larval tank; and (D) larvae fed rotifers cultivated with live microalgae and daily addition to the larval tank of live microalgae) were tested in order to determine if freeze-dried microalgae (Nannochloropsis oculata) was as good as live microalgae for larval rearing at two stages (for rotif er production and into larval tanks). The results showed that larvae c an be reared successfully using only freeze-dried microalgae with a su rvival of approximate to 100% and without altering water quality. Fift een-day-old larvae were obtained with normal growth in length (5.56 +/ - 0.14 mm) and weight (104.46 +/- 1.86 mu g) and with good development of the digestive tract and other associated organs (liver, pancreas). The presence of microalgae (freeze-dried as well as live) in the rear ing tanks significantly influenced growth, survival and histological s tatus. (C) 1998 Elsevier Science B.V. All rights reserved.