Effect of Weaning Diets with Different Weaning Periods on Survival and Rearing Performance of Gilthead Sea Bream, Sparus Aurata Larvae = تأثير أعلاف الفطام مع فترات فطام مختلفة على الحيوية وكفاءة رعاية يرقات الدنيس

This study was carried out in the Marine Governmental Hatchery of the General Authority of Fish Resources Development (GAFRD), in Alexandria in cooperation with the Faculty of Agriculture (Saba Basha) Alexandria University, Egypt. The aim of the work was to reduce production costs of marine hatcheries of gilthead Sea bream, Sparus aurata during the larval rearing period by developing an effective and applicable program for Early weaning from the very expensive live food. Two types of weaning diets were tested pelleted diets purchased from INVI Company and the prepared micro diet (MD). The protein content in the first diet consisted of 56% protein and the laboratory diet contained 51.4% protein. The experiments were carried out in twelve aquaria containing 35 liters of seawater with salinity of 38 ppm. Four hundred larvae of gilthead seabream were transferred to each aquarium, 13.3 larvae per liter, with (2.2mg) average initial weight and water flow of 245 ml/min/aquarium. The larvae were fed 6 times daily (from 8:00 am to 6:00 pm at the rate of one meal every two hours). The nutrition protocol was implemented according to the FAO Guide (Moretti et al ., 1999). The experiment lasted 55 days. During this experiment, the study examined: water quality, growth performance