Dietary lipid requirement of juvenile hybrid sturgeon, Acipenser baerii female x A. gueldenstaedtii male

A 10-week growth trial was conducted to determine the dietary lipid requirement of juvenile hybrid sturgeon (Acipenser baerii female x A. gueldenstaedtii male) (initial body weight, 66.7 +/- 0.11 g). Seven isonitrogenous (crude protein 370 g kg(-1)) diets were formulated to contain various levels of dietary lipid (40, 65, 90, 115, 140, 165 and 190 g kg(-1)) and each diet was fed to triplicate groups of thirty fish at 22.3 +/- 0.8 degrees C in twenty one 1 m 3 concrete tanks. The results showed that specific growth rate (SGR) significantly increased with dietary lipid level up to 115 g kg(-1) (P < 0.05) and then kept constant (P > 0.05). Feed intake (FI) was significantly lower at 40 g kg(-1) lipid diet (P < 0.05) while there was no significant difference between other diets (P > 0.05). Feed efficiency (FE), protein efficiency ratio (PER), or protein retention efficiency (PRE) showed no significant difference between diets (P > 0.05). Energy retention efficiency (ERE) was lowest in the fish fed diet with 40 g kg(-1) lipid (P < 0.05). Fish serum triglyceride (TG), total cholesterol (TC), phospholipid (PL) and low density lipoprotein cholesterol (LDL-C) were positively correlated to dietary lipid level (P < 0.05). The contents of dry matter, lipid, energy in whole body, and the contents of dry matter and lipid in dorsal white muscle showed a steady increase with the increasing dietary lipid level (P < 0.05). Broken-line regression analysis indicated the dietary lipid requirement for juvenile hybrid sturgeon was 111 g kg(-1)