|
|||||
|
|
Use of Microbial Flocs Generated from Tilapia Effluent as a Nutritional Supplement for Shrimp, Litopenaeus vannamei, in Recirculating Aquaculture Systems |
|
| Authors: | David D Kuhn Gregory D Boardman Steven R Craig George J Flick Jr Ewen McLean |
| Institution: | Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA; Department of Large Animal Clinical Sciences, Virginia–Maryland Regional College of Veterinary Medicine, Blacksburg, Virginia 24061 USA; Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA; Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA |
| Abstract: | Recovering nutrients in a fish effluent to be used as a supplemental feed for shrimp culture could ease constraints (e.g., environmental issues and high production cost) that have limited the US shrimp farming industry in the past. In this study under laboratory scale conditions, fish effluent was collected from a commercial tilapia farm and nutrients from the waste stream were offered as supplemental feed as either (1) untreated solids from tilapia effluent or (2) microbial flocs generated from the biological treatment of the effluent by reducing soluble chemical oxygen demand >80%. The first feeding trial demonstrated that microbial flocs contributed significantly (P < 0.05) to overall growth while untreated solids did not. Moreover, microbial flocs were larger and contained higher levels (P < 0.05) of protein. The second feeding trial investigated different feeding rates of commercial diets with and without microbial floc supplementation. Weekly measurements of mass and specific growth rates demonstrated that microbial flocs significantly (P < 0.05) contributed to shrimp performance. Weekly food conversion ratios were also reported. Water quality in shrimp systems during both studies was within safe levels, and no differences (P > 0.05) between treatments were observed for dissolved oxygen, nitrate‐nitrogen, nitrite‐nitrogen, pH, salinity, total ammonia nitrogen, and temperature. |
| Keywords: | |