Bovine growth hormone treatment of channel catfish: strain and temperatureeffects 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 circu lar 800-1 tanks and injected once weekly with 2.5 mu g recombinant bovine g rowth hormone (rbGH) per gram body weight, or the saline vehicle. In additi on to the rbGH, and strain treatments, half the tanks were supplied with we ll water of 26.0 degrees C and the other half received water of 21.7 degree s 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 tha n in saline-injected controls. Strain and temperature effects were also sig nificant. Feed consumption was significantly greater with growth hormone tr eatment, higher temperature, and in the USDA-103 strain of catfish. Feed ef ficiency was significantly better in rbGH-injected fish. The effect of temp erature on feed efficiency was also significant, higher temperature treatme nts performed better. Growth hormone enabled channel catfish to grow better at lower and higher temperatures than saline-treated counterparts. (C) 200 0 Elsevier Science B.V. All rights reserved.