Relative use of dietary carbohydrate, non-essential amino acids, and lipids for energy by hybrid striped bass, Morone chrysops ♀ × M. saxatilis ♂

Fish fed the control diet with 25% CHO or high-lipid diet had significantly (P < 0.05) higher weight gain (WG) than those fed the 25% NEAA or 0% CHO diets. Fish fed the 25% NEAA or 0% CHO diets had similar WG. Protein efficiency ratio (PER) of fish fed the 25% CHO control diet was significantly higher than fish fed the 25% NEAA diet but did not differ significantly from those of fish fed the high-lipid or 0% CHO diets. Fish fed the control and high-lipid diets had significantly higher protein productive value (PPV) than those fed the 25% NEAA or 0% CHO diets. Hepatosomatic index (HSI) and hepatic glycogen content of fish fed the 25% CHO control diet were significantly higher than that of fish fed all other diets while their liver protein and lipid contents were significantly lower than fish fed the other experimental diets. Fish fed the high-lipid diet displayed significantly higher intraperitoneal fat (IPF) ratio, whole-body lipid and muscle lipid compared to fish fed the other diets. Results of this study indicated that with diets containing 40% crude protein, and energy supplied by 25% dextrinized starch provided similar growth performance of hybrid striped bass and achieved less carcass lipid deposition compared to an equal supply of energy from lipid. Dietary NEAA (glutamate and aspartate) was converted to hepatic glycogen and carcass lipid, but did not have positive effects on growth performance of hybrid striped bass.