Title: Rearing sunshine bass using diets formulated for summer water temperatures Authors
|Gaylord, Thomas -|
Submitted to: Texas Aquaculture Association Annual Conference and Trade Show
Publication Type: Abstract Only
Publication Acceptance Date: January 22, 2014
Publication Date: N/A
Technical Abstract: Elevated water temperatures are common in hybrid striped bass or Sunshine bass (HSB; Morone chrysops x M. saxatilis) production ponds during summer months in the southern US. Median daily water temperatures often exceed 30 C from June through September. This experiment was conducted to extend and refine results of earlier tank studies on diets formulated for summer water temperatures to earthen pond production of HSB. Diets tested contained 35, 38, or 41% digestible protein and 18% lipid. Diets were balanced on an available amino acid basis to the profile of HSB muscle and supplemented with lysine, methionine, and threonine at the equivalent of 350, 380, or 410 g/kg muscle protein. Each diet was fed to HSB (mean weight: 121 g) stocked into three replicate ponds. Fish were fed daily to apparent satiation. Mean water temperature was 29.3 C from mid-June to mid-September. Dietary protein did not affect significantly fish production or bioindices. At harvest, weight gain averaged 490%, final fish weight averaged 744 g/fish, gross fish yield averaged 5,243 kg/ha and feed conversion ratio averaged 1.36. Bioindices averaged 2.86% for hepatosomatic index, 8.48% for intraperitoneal fat, and 50.5% for muscle ratio. Results suggest that the high dietary fat speeds growth and spares protein during summer growth, but may be too high given the percent body fat observed.