What They Did Back Then

* Master of Science in Aquaculture completed 2002, University of Guelph

Advisor: Professor Richard D. Moccia

Biochemical Oxygen Demand (BOD) of Fecal Waste Produced  by Rainbow Trout) ( Oncorhynchus mykiss) Fed Four Different Diets:

Modeling Environmental Loading of Waste Outputs and BOD in Freshwater Ecosystems


Feed wastage and fecal production from cage aquaculture facilities are the major contributors to nutrient enrichment of receiving water bodies and underlying sediments. The developments of diets that are more digestible in nature are hypothesized to reduce fecal output therefore, reducing the biochemical oxygen demand (BOD) load to the environment.

Four diets were allocated to 1,040 rainbow trout (Oncorhynchus mykiss) that were randomly assigned to 12 fiberglass tanks. The diets included 2 with modified ingredient profiles to increase digestibility of the feed ( LBOD-R, LBOD-N), a high –energy feed ( HI-ENERGY), and a regular feed (REG). Manure from the tanks was harvested bi-weekly and BOD5 was performed on the feces. No significant statistical differences for the fecal BOD5 were observed among the diet treatment groups. 

The fecal BOD5 data acquired, accompanied by data resulting from research on the growth performance of the fish on the four treatment diets, were used as examples in a model developed to estimate maximum environmental BOD, solids, phosphorus, and nitrogen loading. The Hypolimnion Environmental Load Prediction ( H.E.L.P.) Model were serve as a tool to farmers to predict their environmental impacts on their particular site based upon different feeds used.