The effects of oxygen supplementation on growth and survival of rainbow trout (Oncorhynchus mykiss) in different stocking densities

In this study, the effects of oxygen supplementation in different stocking densities of rainbow trout (Oncorhynchus mykiss) on the specific growth rates (SGR), feed conversion ratios (FCR) and survival rates were investigated in a commercial-scale culture system. High density cultures were maintained in a total of nine (۱۲ m۳) flow-through systems supplemented with O۲. Initial stocking rates for ۳ different treatments with three replicates were ۲۶.۸۸±۰.۳۰ (low density), ۳۶.۷۲±۰.۲۶ (medium density) and ۵۵.۰۳±۰.۱۴kg m-۳ (high density), corresponding to a total of ۵۸۰۰, ۸۰۰۰ and ۱۲۰۰۰ fish/tank, respectively. Water flow rate for each tank was maintained at ۱۱±۱.۱ L sec-۱ (۶۶۰ L min-۱) over the study period for each raceway, and the temperature was ۱۲.۳±۰.۸°C throughout the experimental period. At the end of the study, there were no significant differences in the survival rates and SGR among treatments (p>۰.۰۵). However, FCR was negatively affected in the high density treatment (p<۰.۰۵). Overall, our results indicated that oxygen supplementation supported fish growth and survival in high stocking densities. However, high production cost is prohibitive and further studies are required to reduce costs.

Keywords:

Rainbow trout , Intensive culture , Stocking density , Oxygen supplementation