| Abstrakt: |
The effects of various levels of dietary energy and protein on the growth rate, body composition, and muscle RNA:DNA ratios of walleyes (Stizostedion vitreum) were studied during a 10-week period. A factorial treatment design was used to provide three levels of dietary metabolizable energy (ME), 3,310, 3,530, and 3,750 kcal ME/kg diet, and four levels of protein, 37, 44, 51, and 58%. Both dietary protein and energy affected weight gain and length change (P < 0.05), but no interaction effects were observed. Maximum weight gain occurred with the 51% protein and 3,530 kcal ME!kg diet. Neither dietary protein nor energy affected the condition factor of the fish. The percentages of body fat, protein, ash, and moisture were affected by dietary protein (P < 0.05), but only body fat and moisture were affected by dietary energy (P < 0.05). The percentage of body fat decreased as dietary protein was increased, but it increased as dietary energy was increased. The percentage of body moisture varied inversely with the percentage of body fat. The percentage of body protein increased as the dietary protein was increased, but it was not affected by dietary energy levels. The percentage of body ash decreased linearly as dietary protein (P < 0.06) and energy (P < 0.08) were increased. The weight gains of fat, moisture, ash, and protein were related quadratically (P < 0.05) to both dietary protein and energy levels. No interaction effects of dietary protein and energy were observed on body composition. Dietary protein, but not dietary energy, affected the RNA:DNA ratio of muscle tissue (P < 0.03). The RNA:DNA ratio increased as the dietary protein was increased to 51% protein, but the ratio was reduced by a further increase of dietary protein to 58%. [ABSTRACT FROM PUBLISHER] |
Plný text