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Department of Forestry and Natural Resources * Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
Two experiments were conducted to determine the dietary lysine requirement of juvenile hybrid striped bass (Morone saxatilis x M. chrysops). In both experiments the diets contained 35 g crude protein/100 g diet (10 g crude protein supplied by casein and gelatin and 25 g crude protein supplied by crystalline L-amino acids) and contained graded levels of L-lysine·HCl resulting in eight dietary treatments. Diets were fed to triplicate groups of fish and ranged in dietary lysine concentration from 1.2 to 2.6 g/100 g of the dry diet in Experiment 1 and from 0.8 to 2.2 g/100 g of the dry diet in Experiment 2. Weight gain and food efficiency data from Experiment 1 indicated the dietary lysine requirement to be between 1.2 and 1.4 g/100 g of the dry diet. Weight gain, food efficiency and serum lysine data from Experiment 2 confirmed the requirement to be between 1.2 and 1.4 g/100 g of the dry diet. Broken-line analysis of weight gain and food efficiency data from Experiment 2 indicated the dietary lysine requirement to be 1.4 ± 0.2% of the dry diet, or 4.0 g/100 g of the dietary protein. Changes in the relative proportions of dietary lipid and carbohydrate between the two experiments, although maintaining similar gross energy levels, did not alter the lysine requirement estimate of juvenile hybrid striped bass.
KEY WORDS: hybrid striped bass lysine requirement amino acid requirements fish
1 Supported by the Purdue Agricultural Experiment Station (IND 059054), contribution number 13092.
2 To whom correspondence and reprint requests should be addressed.
Manuscript received 31 July 1991. Revision accepted 13 January 1992.