The effects of exogenous bovine growth hormone and placental lactogen on juvenile striped bass Morone saxatilis feed and growth efficiency

Striped bass Morone saxatilis under normal pond-reared conditions usually r equires 14-18 mo to grow out to market weight, This includes a winter of co mparatively slower growth which could possibly be overcome through hormonal ly induced acceleration of growth. Thus, the objective of this experiment w as to test the hypothesis that bovine growth hormone and bovine placental l actogen increase growth in striped bass in a dose dependent manner. A secon dary objective was to determine the effect of these hormones on body compos ition. Variables tested were weight gain, length gain, condition factor, fe ed conversion, and body composition. Fish injected biweekly with 10 mu g/g body weight, bovine placental lactogen (P < 0.09) or bovine growth hormone (P < 0.11) increased body weight. Fish injected with 1 or 10 mu g/g body we ight bovine placental lactogen (P < 0.10) or bovine growth hormone (P < 0.1 0) increased body length during the 12-wk study period. Proximate analysis indicated that bovine growth hormone increased protein content (10 mu g/g; P < 0.10) and decreased fat content (1 and 10 mu g/g; P < 0.10). No signifi cant differences occurred in feed conversions. We conclude that bovine grow th hormone and bovine placental lactogen are effective in increasing body g rowth in striped bass.