محمد حسین خانجانی

bstract The aim of this study was to investigate the effect of different levels of wet biofloc on water quality and feeding, growth performance, survival, and body composition of banana shrimp Fenneropenaeus merguiensis. The experiment consisted of the control group (feeding 100% commercial feed and 50% water exchange per day without biofloc) and four treatments in which portions of the commercial feed were replaced by wet biofloc (T2: 25%, T3: 50%, T4: 75%, and T5: 100%) with limited water exchange. Postlarvae of banana shrimp (mean ± SD weight of 4.5 ± 0.68 mg, density of 5 postlarvae/L) were experimentally held in fiberglass tanks with 170 L of seawater with salinity of 28‰ for 30 d. An acceptable range of total ammonium nitrogen and nitrite nitrogen was maintained in rearing tanks with wet biofloc throughout the experiment despite minimal water exchanges, but total ammonium nitrogen and nitrite nitrogen were significantly higher in the control group. Postlarvae fed with 25% wet biofloc had significantly higher total biomass (222.36 g) and survival (76.27%) compared with the other treatments. A comparison of banana shrimp fed with 25% or 50% wet biofloc and those fed with 100% commercial feed did not show a significant difference in body composition. The highest levels of body ash (12.7% of dry weight) were obtained in banana shrimp fed with 100% wet biofloc. In general, it was found that up to 50% of commercial feed can be replaced with wet biofloc (developed under the conditions of this study) without compromising growth performance, survival, and carcass quality of banana shrimp postlarvae.