Utilization of wastewater-grown zooplankton: Nutritional quality of zooplankton and performance of silver perch Bidyanus bidyanus (Mitchell 1838) (Teraponidae) fed on wastewater-grown zooplankton

Zooplankton grow in the last stage of water purification at the Werribee Sewage Treatment Lagoons (WSTL) and the resource is huge and unutilized. Daphnia carinata and Moina australiensis are the dominant species at the WSTL. The protein content of D. carinata and M. australiensis was 54.80% and 64.80%, respectively. Analysis of zooplankton showed that both essential and nonessential amino acids were present at a level that was higher than control diet. Silver perch fed on D. carinata exhibited better growth, better food conversion ratio (FCR), protein efficiency ratio (PER) and apparent net protein utilization (ANPU), which were not significantly different from the control diet ( P  > 0.05). Heavy metals concentrations were at very low levels in fish fed on wastewater-grown zooplankton.     

Effects of Dietary Supplements on Growth Performance and Phosphorus Waste Production of Australian Catfish,Tandanus tandanus,Fed with Diets Containing Soybean Meal as Fishmeal Replacement

Effects of dietary phytase, amino acid (AA), and inorganic phosphorus (P) in soybean meal (SBM) diets on the growth, feed utilization, and P waste of Australian catfish, Tandanus tandanus, were evaluated. In Experiment 1, SBM replaced 30% of fishmeal (FM) protein in the four test diets, supplemented with phytase (1000–3000 FTU/kg). In Experiment 2, SBM replaced 45% of FM protein in the four test diets, supplemented with phytase, AAs, inorganic P, or their combinations. Inclusion of 3000 FTU/kg significantly improved growth performance and feed utilization of catfish. Ortho‐P waste was significantly lower in fish fed with SBM diets. At 30% FM protein replacement, dietary SBM did not reduce the total P waste of catfish while dietary phytase significantly did. At 45% FM protein replacement, phytase alone did not significantly improve the growth and feed utilization of catfish fed with SBM diets while significantly better results were obtained when both phytase and AAs were supplemented. Dietary inclusion of inorganic P significantly decreased P utilization and increased P waste of the fish. Dietary phytase significantly improved P utilization of catfish in both experiments.     

The use of <Emphasis Type="Italic">Daphnia magna</Emphasis> immobilization tests and soil microcosms to evaluate the toxicity of dredged sediments

Purpose  

This paper evaluates the feasibility of using the buffering capacity of natural soil for the remediation of dredged material before being disposed in soil landfills. To achieve that, an Integrated Soil Microcosms (ISM) system was designed to produce elutriates and leachates from the sediment/soil percentage mixtures. Furthermore, to investigate the biological effects of the contaminated sediments, the toxicity behavior of leachates and elutriates was assessed and compared by performing acute (48 h) toxicity assays with the cladoceran Daphnia magna as test organism.