Effect of Altering Dietary Protein: Energy Ratios on Juvenile Pallid Sturgeon Growth Performance

Abstract

Pallid Sturgeon Scaphirhynchus albus are endemic to the large, freshwater, river systems of North America and have long been prized for caviar production. Declining wild populations and fishing prohibitions have created interest in the culture of these fish. Protein and energy are often the first nutrients examined when attempting to identify diets appropriate for a novel culture species. Therefore, the present study evaluated the effects of different dietary protein: energy ratios on Pallid Sturgeon growth and body composition. Twelve semipurified diets composed of four crude protein (CP) levels (32, 39, 46, and 53%) and three gross energy (GE) levels (3,600, 4,200, and 4,800 kcal/kg) were fed to 180 juvenile Pallid Sturgeon for 18 weeks. Diets were offered to triplicate groups of five fish each in separate tanks. Fish were fed 2% body weight daily and sampled every 3 weeks. Mean weight gain and body composition were significantly affected by GE content of the dietary treatment (P ≤ 0.05), but not by dietary CP or protein and energy interactions (P > 0.05). The most energetically dense diets yielded significantly larger fish than the least energetically dense diets and the intermediate diets were not significantly different from either extreme. These results suggest that Pallid Sturgeon are able to perform similarly across a wide range of protein: energy ratios (79-147 mg protein/kcal), as long as adequate dietary energy (≥3,800 kcal GE/kg) is provided and essential amino acids are not limiting. This research is the first to evaluate dietary protein: energy ratios for Scaphirhynchus sturgeon culture. Received June 20, 2013; accepted August 14, 2013. © 2014 Taylor and Francis Group, LLC.