Evaluation of the effects of an oxygen injection system on the growth, hematology, and immunity of lake trout

Fingerling lake trout (Salvelinus namaycush) were reared for 64 d at three pressures of dissolved gases, expressed in relation to saturation values (▵P)–untreated (control) water, ▵P = 10 mm Hg; water treated by column degassing with air, ▵P = 9 mm Hg; and water treated with an oxygen injection system, ▵P = −20 mm Hg. Dissolved oxygen concentration for experimental groups was increased with column degassing by 7.8% and with oxygen injection by 8.7%. Nitrogen level was reduced 2.2% with columns receiving air and 7.4% with the oxygen injection system. There were no differences in production, mean lengths, or mean weights among fish reared in the three treatments. Hematocrit, plasma protein levels, and mean antibody microtiters to injected Salmonella H antigen were not different among fish from the three water treatments.