Bovine growth hormone treatment of channel catfish: strain and temperature effects on growth, plasma IGF-I levels, feed intake and efficiency and body composition

Channel catfish from two strains, USDA-103 and Norris, were reared in circular 800-1 tanks and injected once weekly with 2.5 mu g recombinant bovine growth hormone (rbGH) per gram body weight, or the saline vehicle. In addition to the rbGH, and strain treatments, half the tanks were supplied with well water of 26.0 degrees C and the other half received water of 21.7 degrees C. Growth rate, plasma insulin-like growth factor I (IGF-I) levels, feed consumption and body fatness of the fish injected with rbGH were higher than in saline-injected controls. Strain and temperature effects were also significant. Feed consumption was significantly greater with growth hormone treatment, higher temperature, and in the USDA-103 strain of catfish. Feed efficiency was significantly better in rbGH-injected fish. The effect of temperature on feed efficiency was also significant, higher temperature treatments performed better. Growth hormone enabled channel catfish to grow better at lower and higher temperatures than saline-treated counterparts. (C) 2000 Elsevier Science B.V. All rights reserved.